Tasso Assignment Example | Topics and Well Written Essays - 250 words

Tasso - appointee Exampleattest to his influence on various artists expression and interpretation of his significant works of which La Gerusalemme liberate was considered his masterpiece.The life and works of Tasso enlighten art enthusiasts in the realization that the concept of love unsuccessful might have contributed to his insanity as it still happens in contemporary times. In Amita, the object of the sheepherder heros amorous desires, Sylvia, found pleasure in engaging in a chase for her heart even to the point of death. Tasso, thought to have represented himself in the character of Thyrsis, revealed his inner thoughts done analogies of love with goddesses and beams of emotions like silver and gold insurmountable, ephemeral, distant. He sees this as a bondage ever want freedom and hope of realization even in the face of death.Tasso was credited for various works of humanities including Rinaldo, a narrative poem meant to combine the regularity of the Virgilian with the attr actions of the romantic epic (NNDB, par. 1) Torrismondo, a meritorious catastrophe Monte Olivet, a poem considered as dull by critics Gerusalemme Conquistata, a grim revision of his masterpiece and Le Sette Giornate, a prosaic composition in Italian blank verse ((NNDB, par. 1). Despite his unhealthiness and notoriety, he was to be crowned in Rome byPope Clement VIII as Italys Poet Laureate but died one day before the coronation. (Liukkonen, par. 11) The themes and poetic expression of Tasso clearly reflected the life of the poet with its essential touches of poverty amidst living in the presence of dukes, duchess, prince and princess of his era. Like his Aminta, his life ended just on the scepter of being ascended into the realization of his

Chocolate Research Paper Example | Topics and Well Written Essays - 1000 words

Chocolate - Research Paper congresswomanIt is made up of cocoa solids and cocoa butter only and hence it is chocolate in its simplest comprise (Hawkins 19). It is bitter and thus is not a popular choice for most people who love chocolates. It is commonly utilise as an ingredient in baking and cooking. It adds chocolate flavor to cakes and brownies since it is smooth and rich in cocoa butter.Like unsweetened chocolate, semi-sweetened chocolate is mainly utilise for cooking purposes. They are mainly used for baking chocolate chip cookies although they can be used to bake many early(a) commodities. It is unruffled of dark chocolate (cocoa butter and cocoa solids), prick and vanilla that are an emulsifier. The percentage of sugar does not exceed 50% the mass of the chocolate (Hawkins 20). The ratio varies depending on the manufacturer. This form of chocolate has a nice balance between sweetness and chocolate and thus and work well in most recipes. bittersweet chocolates contain at least 35% of cocoa solids. They are dark in color and brace rich flavors. Normally they have graduate(prenominal) percentages of flavonoids although their percentage depends on the manufacturer. They contain chocolate liquor, cocoa butter, and sugar. The high percentage of chocolate liquor content makes it dark. It is can be eaten and can also be used for baking purposes.It contains chocolate flavor, cocoa butter, and sugar. The percentage of cocoa solid ranges forms 35-45% depending on the manufacturer (Hawkins 20). The percentage of sugar is more than 50%. It is not easy to differentiate them with semi-sweet chocolate.It is made up of milk solids, sugar, and cocoa butter. 10 % is composed of cocoa liquor, and at least 12% is made up of dry milk solids (Hawkins 21). It is broadly eaten as candy bars and is preferred by most people who love eating chocolates. It was root developed by Daniel Peter, a Swiss candymaker, in 1876.It is made up of cocoa butter, milk, and sugar. Unl ike other

Entrepreneurship and starting a small Business Term Paper

Entrepreneurship and starting a small Business - Term Paper ExampleFinally, conclusions with call findings and appropriate recommendations have been made.Starting ones have got business is an exciting, promising and high-risk marriage offer that usually stems from one single idea or a need. Study related to this process, usually referred to as entrepreneurship, has emerged as one of the most important outcomes of globalization. While signifi targett part of a nations economic growth is through small business entrepreneurs, failure of this section of businessmen cannot be rule out. In the current study, focus will be on efforts to identify various factors responsible for the achievement of small businesses and the challenges they face. An attempt will be made to list the core elements of successful entrepreneurship based on literature study and analysis before concluding with key findings.In his magazine article, Todorvic (2004) expresses that origins of entrepreneurship can be t raced to early last century and is yet under lot of debate concerning its definition or material meaning. He asserts that entrepreneurship is such a vast multidimensional and dynamic aspect of conducting business in the globalized worldly concern that it has been given multiple definitions from varied perspectives. Quoting various definitions from different people, Todorvic (2004) mentions that entrepreneurship, for instance, is concerned with starting ones own business entrepreneurship is the process by which new products, services or outcomes are created by people that can be recognized with certain specific characteristics. Specific characteristics have been associated with entrepreneurship, such as innovation, focus, discipline, passion, self-confidence, positive attitude, and doggedness (Nieuwenhuizen & Machado, 2004). Koester (2010) asserts that an innovative opportunist is the one that makes use of an opportunity in the marketplace and converts this into a promising busine ss. Moreover, Koester (2010) likewise mentions that good interpersonal

Cost Accounting Case Study Example | Topics and Well Written Essays - 500 words

Cost Accounting - Case airfield ExampleThus for a manager, who has an authoritative style of leadership like the said CEO, could get things flat without consulting managers or employees who can can readily agree. However, the budgeting process should theoretically and practically require participation from meat and even unhorse managers to be effective. Managers may not just be working for their pay. They are overly human beings who would prefer that their contribution to the organization should also be recognized and valued by circumspection by making them part of the decision-making process.Although a chief executive officer must plan, organize and controls activities, at the same time he must also lead people in the organization toward skill of objectives. As manager, he influences his subordinates, who cannot be presumed to need creativity. Subordinates or followers may even contribute for the amelioration of the plan because at the planning stage the CEO can sense possi ble problems that they have and strategies on how to counter them can become material part of the budget process. A typical organization has operative areas or departments with conflicting interests and priorities as the process essentially requires making an optimum use of the limited resources. The budget process entails managers to use resources which are tied with activities and that are needed to attain set objectives. If the middle and lower managers are not consulted in budget process, they would most probably not support fully the goals per budget as set by the CEO.It must be noted that a erect CEO is good delegator (ZweigWhite ,2010) and this is the essence of an organization person. Setting the goals and just telling his subordinates to strive for their attainment would be an act of lack of trust to his lower managers. If the said CEO realizes that his people would prefer to decide with him, working with the

SEMCO Company Strategy Essay Example | Topics and Well Written Essays - 1750 words

SEMCO Company Strategy - undertake ExampleTherefore, this paper will bank on a critical explanation of the applications of schools of system that argon exploited in SEMCO. Different companies use different strategies to record their preferred results. In many instances, companies pass to advocate for development and deploy skills that will be used in recording positive growth. This is make by ensuring the people that are employed are competent in their work and use their skills accordingly.. This is due(p) to the ever evolving market. As such, the market needs to be encountered with different strategies. This is also heightened by developing and deploying strategic flexibility, which is directly reflected towards technological emanation. For instance, with the improvement in technology, many companies have to improve. This is by using technological advancement in their service furnish. In recent times, many companies have been noted to invest heavily in acquisition of new mach inery and equipment (Furrer, 201034). This is not a point to brag, but it is an advancement to make service provision even get out. Purchase of new technology ensures a unions production is improved in quality and quantity. Similarly, the goods that are produced will be of increased value (Semler, 200054). This will prompt customers and clients to use more than of the goods. With such a drill, a company is most likely to record positive results, which increases its financial muscle. As a matter of fact, SEMCO decided that its environment was a core factor that could lead to its grater performance. As such, ever-changing the environment would be a prudent idea in increasing its performance. This is garnered from the learning school of view, which banks on making a positive environment in business (Kazmi, 200856). In making this a reality, the pissed encouraged the staff and management to exchange idea oh=n how the firm could make an improvement. This is an opportunity where ever y the staff members are given an opportunity to express their views on how performance of the governing body could improve. As such, the organisation has a pool of ideas to choose from. With such a large pool of ideas, the organisation has a better position of implementing the best. This is a position that many organisations do not have but they will never try such a manoeuvre, minding the risks that are involved (Jansson, 200823). This was followed by the practical part of experimenting ideas that cropped up in the organisation. Since organisations do not engage in risky activities, they have to study and evaluate the viability of the activities. This was heightened by question and exchange of ideas to ensure the best routine was designed (DAngelo, 200952). With time, SEMCO had obtained competent skills and had competent personnel that could direct the investments. As such, they were prepared to exploit all the available loopholes in businesses. As such, the business was growing at a steady rate. SEMCO Company has been recording successful results in the market, yet it does not have a compose strategy or plan. However, it has deployed the prescriptive school strategy, which is about planning, designing and positioning. It is in the market and making a positive accrual due to its activities that are concentrated on the customer market. With such a drill, the company is on the verge of making lucrative profits that are not linked to any strategy that is in writing or planned (Suneja, 200213). SEMCO Company planned that its businesses should be increasing in each financial year. However, it did not strategise on its expansion rate to a particular point. In such a drill, it ensured that transformation would continue in every year (Semler, 200055). For

Environmental Scan Assignment Example | Topics and Well Written Essays - 1000 words

Environmental Scan - Assignment ExampleThe program is solely amenable for health services and training opportunities, along with valuable educational programs.Regina Food Bank has been sustaining its operations from retiring(a) many years. However external forces tend to affect operations of this charitable organization. There atomic number 18 cardinal major forces in external environment as per PEST model such as political, economic, affable and technological forces. This project has been incorporated in Regina located in Canada.Political power is in estimation of Regina Food Bank. Its main aim is to eradicate any form of hunger issues from the country. The government had recently inform a lump sum amount to be donated to Regina Food Bank. This kind of coronation would be make in terms of capacity building in community and voluntary sector. Political conditions at generation are not stable due to frequent elections and this in turn proves to be a bane for charitable organ izations.Economic factors mainly comprise of effect of recession on charitable organization. This encompasses various phenomenons same(p) lower income of donor, increased service demand and stiff competition in context of declining funds of government. agate line security is a vital issue for donors and this affects operations of charitable organizations. When disposable income is low then it negatively affects donation habits of individuals. Reduction in interest rates is good for businesses and home-owners but it has adversely affected charities. foodstuff excitability reduced overall income from investments and reserves for many firms. The charities usually are dependent on investment factor. This kind of dependency will be influential since larger portfolio portion is held in shares. Market volatility also plays a major role for charities in context of pension funds. Pension funds are usually bounded within equities and hence declination in stock value creates large deficits. monetary instability and low interest

Dual-career families Essay Example | Topics and Well Written Essays - 250 words

Dual-career families - Essay Example, couples in a dual-career relationship have jobs that require a high degree of rousement and effectively the developmental nature of the professions these couples engage in is high. In effect, such couples pursue careers while still performing their main(prenominal) roles in parenting. These relationships have certain characteristics such as economic rewards for the couples and ultimately to the family. In addition, the family derives an added social prestigiousness when both parents are working. Furthermore, a personal investment on the part of both partners is evident when they commit their time and energy to their careers. However, the commitment of time and energy can influence the relationship of the couples within the family setup.Hamner & food turner (2000) noted that, many working couples with children experienced conflicts in their work and family relationships effectively influencing their performance and creating stress at both work and in the family. Such conflicts influenced greatly on the childrens behavior. In this regard, one super issue in dual-career families c formerlyrns absentee parents. As such, house helps, who at most instances lack the basic knowledge in parentage, have the biggest responsibility on children. On the other hand, commitment to work drains the energy out of the parents once they reach home and eventually fail to spend quality time with their children. Effectively, children will pick behavior, at times undesirable, from other people since the parents are not monitoring their children progress closely as should be the case.Faced with such challenges, there are various ways that dual-career families can overcome them. According to Hester & Dickerson (1984), dissimilar programs devised by extension personnel are essential in training couples on ways of improving their relationship. Such programs establish unique responsibilities in each relationship advising each couple on the top ha t way to parent their children while both juggle with their careers,

Research and Application Business Paper Example | Topics and Well Written Essays - 750 words

And Application Business - Research paper ExampleThis Strategy emphatically promises to increase business and maintain a combative edge in its own segment for JetBlue. The Customer Value Proposition of JetBlue The marketing strategy and its winner so removed suggests, JetBlue has relied heavily on Operational excellence as the thrust area of its Customer Value Proposition. The success of the airline so far has been attributed by its focus on an array of operational goals like maintaining a high level of customer service with low costs and stimulating demand with low fares. They distort to maintain a sustained growth pattern by increasing frequency on their real routes. The results have shown that such initiatives have been well received by the market and the customers have responded well to these efforts. This is but accentuated by feats like attainment of highest completion factor, the highest on time performance and the lowest incidence of mishandled bags. These achievements invent a high level of operational and management excellence. They obviously enhance the customer experience and apprehension and augur well for the business. The airline strives to achieve competitive advantage through customer intimacy in certain areas, For example, the high level of customer service measures like maintaining transparency in operations provide to the value proposition. However, it does not succeed in attaining customer intimacy, though it does succeed in achieving customer allegiance to an close. It also makes effort to achieve product leadership. However, the efforts in the direction like increasing Live TV channels from 24 to 36 new aircraft and leather seats are not the source of competitive advantage, though they do mean product differentiation to an extent. b) Business risks The 10 K/A of JetBlue pass over an array of risks that could harm the business to some extent or the other. However, amongst them the risks that could really affect profits to an ex tent wherein the ability of the airline to meet the stockholders expectations could be threatened are as mentioned hereunder. The basis of differentiation of these risks from the rest set of risks is the extreme nature of consequences that they may have on the profits of the company in a relatively short span of time. Besides, once incurred, the said risks will require considerable effort and resources to direct and control. Last but not the least, the risks mentioned here are the ones specific to Jet blue and not the ones veneer the Airline industry in general, since the general risks are usually responded to founder with the industry and Government help. In addition, the stockholders understand and are already more aware of such risks and thus the expectations of the stockholders regarding these risks can be better managed. As such, these risks are more imminent in nature. The critical Risks a. If JetBlue fails to implement their growth strategy, the business is at a great risk . The growth strategy is channelizeed at increasing the number of flights in underserved and overpriced areas. The aim is to maintain high quality customer services with low fares and generate more demand. The Low fares are to be compensated for with a high level of operational excellence. This will considerably make up for the low fares and bring costs down while maintaining the rate of bookings at the same time. This means a high profit margin

Vietnams Declaration of Independence Case Study Example | Topics and Well Written Essays - 500 words

Vietnams proclamation of emancipation - Case Study ExampleApril 27, Captain Patti beged Ho ki Minh to all(prenominal)ow the OSS aggroup work with the Annamites with the intention of gathering intelligence on the Japanese. Ho agreed to the Captains request and set up a camp in the jungle that would later be Viet Minhs headquarters. It is cost noting that all requests made to Ho by the United States, he agreed to. In his DoI speech, Chi Minh used the second paragraph of Americas 1776 resolve of Independence to assert his point. He states that Vietnams wish to be a sovereign nation is in agreement with the principles of humanity and adjoinity. He barely states that all Vietnamese, like any other sovereign citizens, have a right to life, liberty and the hobby of happiness. According to Ho, this statement means that all men, irrespective of any differences, have a are all born equal at put up and that freedom cannot be taken away, meaning the rights at from birth are inalienab le. In emphasizing these principles, Ho states that the same principles were used by the United States in the 1776 Declaration of Independence. Ho goes on to point out that the same principles were the foundation of the 1791 Declaration of the French Revolution on the Rights of Man and the Citizen. The French declaration mainly states that all men are born free, have equal rights, and must at all times be free with equal rights. If these principles were reasserted in the Declaration of Independence and the Declaration of French Revolution, then they should be applied to Vietnams Declaration of Independence as well.

Knowing Your Audience Paper and Communiation Release Essay

Knowing Your consultation Paper and Communiation Release - Essay ExampleImmediately rescue efforts began, but two days later, an otherwise(prenominal) shaft collapsed halting the rescue operation of the crews for many hours. Indeed, in such a situation, the keep company would get to be more cautious in how the world is notified of the incidence (Lusted, 2012).Basically, there are two slipway in which the company would be expected to communicate information. The first being directed to the families of the workers trapped, the second to the other employees and finally, to the press. Those chosen to relay the information would be expected to be more careful so as to keep the goodwill of the company unaffected while ensuring that all the information is truthfully and accurately conveyed (Lundgren and McMakin, 2011). This whitethorn be achieved by knowing the potential needs of the families of the miners and that of the companys employees. In this respect, the family members need eas e and the assurance that the company did its best to help save lives and prevent further losses. The employees need the assurance that the company is concerned about their safety and welfare.The potential needs of the families of trapped miners in receiving a kernel concerning this hazard would include among other things a detailed information of any potential dangers to the trapped miners, clear steps the company is taking with actual details and times, in order to convince the families that no opportunity or expense is being spared by the company to rescue their loved ones. It is also critical at the plan of attack of the disaster to provide information relating to the identities and number of miners trapped (Lundgren and McMakin, 2011).The potential needs of employees of the company in receiving the message about this incidence would include knowledge of the identity, the number of colleagues trapped, and the efforts being made by the company in an attempt to save their tappe d colleagues.

It is about culture(Anthropology) Essay Example | Topics and Well Written Essays - 500 words

It is approximately culture(Anthropology) - Essay ExampleThe end of First World War did not get any moderation to the peasants. First the Socialists took over, and then the Fascists took over from the socialists. But it seemed that the condition of the peasants remained the same. They were first oppressed by the landlords, then by the Socialists, then by the Fascists and the Landlords. The food was always in short supply, meat was a rarity. Ironically during times of war the peasants in the villages fared a lot better than those living in the cities, as they could live of the wild. And umteen people in the cities use to go to the rural area to get some food of there. The exchange system was also very prevalent. People worked for food and traded various items to sustain themselves. The degradation of Women is also cover very thoroughly in this chapter. They were encouraged not to work. They were also not encouraged to educate themselves. They were broadly encouraged to stay at h ome. The Fascists further painted women who did not marry or bear children or selfish or unattractive. darn Women were expected to be virgin till marriage, men were expected to direct of their virility before that. This created a situation where prostitution thrived. This had a psychological impact on women in Italy long after the war was over.There is a brief coverage of the family structure as well. While the male was the titular head of the household, his wife generally ran the family. Sharing of food with less fortunate neighbors eve though the quantity was low was common. The fascists and the socialists are also given their due coverage and it is not a flattering picture. While the socialists looted shops and farms, apparently to redistribute the wealth, but in earthly concern it was to benefit a few. While the fascists did not make an attempt to cover up their intentions and joined hold with landlords and other wealthy people to wreak havoc on the peasants.

Microeconomics Essay Example | Topics and Well Written Essays - 750 words - 2

Microeconomics - Essay ExampleThe price of a unmatchable carrot baseball field is $10,000, while the price of 100 gallons of tap body of pee is $0.50 (Textbook, 2007). The diamond water enigma proves that the utility of a resource does not necessarily affect its price. The economical explanation of the diamond water paradox is based on the law of demand and supply. The application of this law implies the reason the prices of diamonds are so high is based on the short supply of diamonds across the world (Varian, 2003).The prices of purified water sold in 20 ounce bottle units follow to certain extend same logic as the diamond tap water paradox. Bottle waters price is much higher than the water that comes into mints home through its pluming system. To put the price in perspective with 100 gallons of water a company could prepare 640 twenty once bottles of water which retails at $1 a piece implying the food market cheer of purified bottle water is 1040 times than the value of tap water. The quality of the product, its positive health benefit, its nifty refreshing taste and the formula that provides drinkable water at its optimum state of quality it foundation be to be consumed by humans. The marginal utility of bottle water is very suspect in comparison to tap water. The water in bottles has a market value which makes it an item that can plainly be used to be drank by a person, on the other hand tap water can used consumed orally by humans as well as a material body of other uses such as fro cleaning, to run machinery as a cooling agent, and many other uses. splash water is way cheaper and has more used than bottle water.Water is a valuable liquid that is for the most part available at very low prices for most of the worlds population. In the continent of Africa in general water is not readily available for many villages across the African nation. The utility and value of water for a community is tremendous. If water is in a state of scarcity in a region the social political system is destroyed and a chaotic

UK Courts Essay Example | Topics and Well Written Essays - 1750 words

UK Courts - Essay ExampleSome arguments specifically identify the choice to eliminate exertion by jury in the most complex fraud cases, suggesting that such cases can be more than appropriately heard by a panel of judge or judge and magistrates. Attorney worldwide Lord Goldsmith states it is about justice...making sure serious fraudsters are brought to trial (BBC News, 2005). Kevin Martin, president of the Law parliamentary law is against the new proposal, as he suggests That the problem does not lie with juries, but with poor management of hook cases. There is concern that doing away with juries will erode public confidence in the legal system. This is a legitimate concern. Lack of confidence in the legal system may lead to lack of cooperation with law of nature and others who serve to uphold the law. Interviews with UK citizens indicate that while the jury system can be flawed, it should be hold in all cases. A poll of UK citizens by News Online provides as with insight into public opinion. ane UK citizen believes that the jury system should be upheld at all costs, as failing to do so would suffer the state to relinquish its authority to the victims, in deciding punishment. Another feels that trial by jury of cardinals peers is still the most fair, claiming that judges are made up of social elite, deciding the requisite of us, the common folk (News Online Poll, 2001), which would lead to injustice.

Demand and Supply Essay Example | Topics and Well Written Essays - 1500 words - 1

accept and Supply - Essay ExamplePeople specialize in the production of goods and services -- or more than existentially, as dictated by their environment, heredity, and/or fate in order to alleviate human hurt their own existence included. In the process of pursuit of own self-interests to satisfy needs and wants, individuals succumb to the unintended, occult market forces that compel others to react by supplying necessities to make life even better in an engagement that leaves interactive parties better off as oppose to having excesses of what one produces in abundance, thus the very(prenominal) essence of efficient allocation of resources in the society studied in microeconomics (Stead and Stead, 2009, p.42).Economists are in intellect that harms and quantities are descriptively the most observable attributes of individual interests that interact within a market anatomical structure to facilitate mutually beneficial exchanges as envisaged by Adam Smith (Friedman, 2009, p.14 5). Thus, for the exchange of interests (expressed in term of goods and services) to occur, demand and supply has to exist, but at some costs. From the field of academia to industrial circles, the basic exposit of supply and demand are integrated into the daily actions of the society. To be sure, the theoretical mastery of economics depends untold on the understanding of the theory of demand and supply (Gandolfi, Gandolfi, and Barash, 2002, pp. 5-6). The theory of demand and supply is, therefore, an organization normal that coordinates the production of goods and services (in quantities, often referred to as output) to satisfy societal needs through the market/price mechanism. Intuitively, the price mechanism moderates the exchanges to the point where goods and services delivered by suppliers (supply side) and paid for by the consumers (demand side) always tends towards a severalize balance with reference to the compensation packages received by either side. The dynamics of dem and and supply applies silk hat to a theoretically free market

Final Paper Research Example | Topics and Well Written Essays - 1250 words - 6

Final - Research Paper ExampleWhile he thought that the theory would reconcile religions and cultures, they all turned against such civilization in unity no religion has ever embraced Evolution. There still exists a rift in the theories and myths of origin of man and death.The look of this paper shall be to critically discuss the topic origin and death of man from the various aforesaid(prenominal) perspectives. By so doing, a clear comparison or contrast among different ideologies and myths shall be exposed. unitary of the accusatives is to compare how the topic has also been discussed by Benton Banai (The Mishomis Book), Rainey Gaywish, Dr. Brian Rice (Seeing the World with Aboriginal Eyes), and Vine Deloria Jr. (God is Red). Another objective would be to approve or disapprove the mythology and theories on the origin of man.The origin of man has usually been discussed on the platforms of Creation and Evolution theories. The beliefs and myths of the Aboriginals have always been si delined by many philosophers and scientists. In as much macrocosm and growth seems to be the most universalized and civilized approaches, the Aboriginals are quite rich cultures and myths that need to be understood, as Benton Banai and Vine Deloria describe in their books.Evolution, offers that all living organisms originated from a common ancestor. Evolution has been defined as the procrastinating genetic change that the species usually undergo due to the environmental pressures. The DNA, a vital element of the wight cell, has taken all the living creatures to a single common ancestor. Most animals share the patterns of their DNA. This was before the evolution took fix. The evolution eventually took place and the organisms have been biologically and geographically separated from each other. Evolution took place in three different forms. These are Gradualism, Speciation and the Natural selection. In gradualism, the species take several generations to attain the craved change th at will enhance their

Capstone Checkpoint Essay Example for Free

Capstone Checkpoint tryLooking back over the past nine weeks I must say that a sizeable amount of valuable information has been presented to our class. The reading material, assignments, and class discussions have taught me some valuable lessons in the compass of nutrition. The assignment that I learned the most from was the Week Two assignment about the digestive system. I now understand how the body uses the different types of food, the path food takes as it enters the body, and how the organs, including the salivary glands work in concert in the digestive process. However, my favorite part of Week Two came through the class discussions in the stadium of home remedies. I learned how a change in diet can prevent or help to cure digestive disorders. For example, Diverticulus can be treated at home by beverage plenty of fluid and eating fiber rich foods, such as fruits, vegetables, whole grains, etc. I enjoyed this part the most because I was forced to take medicine for an e xtended period of time and I really did not enjoy that experience.Therefore, learning natural ways to bring relief was truly retrieve for me.Checkpoint from week one, three day diet analysis instructed me how to begin eating healthier. I made the prerequisite changes in my diet and by the time I reached the three day analysis for week six, I noticed some major changes in my eating habits. Currently I notice the different foods on my plate and the nutritional value that each has to offer. I refrain from eating meals (other than grains for breakfast like food grain or oatmeal) that does not include fruits or vegetables. Even on those days when I stop by a fast food place and grab a burger I avoid the fries, and I gather up for extra pickles, lettuce, and tomato, to add more nutrients to the sandwich.

Should Wealthy Nations Be Required to Share Their Wealth with Poorer Nations by Providing Essay Example for Free

Should Wealthy Nations Be Required to partake Their Wealth with Poorer Nations by Providing EssayIn recent years, there is a controversial issue is that the mystifying countries should sh are their assets among the despicableer countries or not. Most of the public agreed that it is a necessary activity to help the poor improve their lives. On the other hand, some tax payers resolutely keep their opinions when they supposed that the governments of poorer nations are liability to take care of their inhabitants by themselves. As a supporter of sharing with the poor, I think that we ask many reasons to establish philanthropic organizations to support the wretch in other countries and territories. Several main reasons provide be analyzed in this essay. Beginning with lack of natural resources, poor nations coffin nailnot take advantages of fertile dirty word to cultivate or minerals to exploit. Moreover, weak education causes many consequences, one of them is a large number of residents are illiterate so they cannot approach modern life by knowledge. Because of that, they always live with the shortage of food, garb and other articles of daily necessities.They do not have enough money and technology to improve the environs so it brings them to need the help of other countries for surviving. Besides, economic crises occur after several years, as a stage of the economic cycle. Given their capabilities and power, rich nations often recover more quickly than their poor counterparts.This federal agency that the poor is not only more prone to negative impacts of economic crises but also in more difficult circumstances. In these cases, if we do not join our hands to offer them financial assistance, thence the gap between the rich and the poor is become wider, lead to the loss of economic balance. When the living shopworn has been improved, they can afford to quality good and the trade all over the world get out be more prosperous. Last but not least, sharin g wealth with the poor is a humanitarian activity, and anyone can do it.This is the best lesson for children about the important of sharing in hard times. From that, the love of human races go forth be larger. However, the government of poorer countries should not only rely on others. They also have to improve their own situation by carrying out the reform in education, changing some unsound customs and hypothesis to obtain the knowledge of the world. In conclusion, if the richer can give their wealth and the poorer can improve by themselves, we will soon have a thriving future.

Black People and Roberta Essay Example for Free

Black People and Roberta EssayIn Toni Morrisons Recitatif, the story is virtually two daughters, Twyla and Roberta. They grow up in an orphanage because their m others could not care for them. Morrison makes it clear the girls come from incompatible ethnic backgrounds but neer states which one is black or white. At one point in the story Twyla comments, We looked akin salt and pepper. I grew frustrated with the story and had to read it several times. I could never determine who was black and white and the lesson I learned should have been it doesnt literally matter. The story begins with Twylas mother dropping her off at the orphanage. She meets Roberta and they become best friends. The bond they share occurs because they were not considered real orphans. They were a calloned kids unlike the other children whose parents had died. One of the stick up times the girls impinge on each other was the solar day of a visitation. On that night, Twylas mother was wearing those ti ght green slacks that made her stooge stick out. Many people have labeled blacks as having larger butts.She could have been black, she could have been a heavy white woman with a large butt, or a Hispanic woman like me. But I automatically stereotyped and went with Twyla has to be black. During the visitation Robertas mother had brought chicken legs. Twyla notices Roberta does not eat the chicken legs. I always thought black people liked chicken more than white people which means Roberta was white since she did not eat the chicken. Or maybe she just wasnt hungry. Shortly after that visitation Robertas mother came to take her home, leaving the girls devastated.They see each other several times by means ofout the years. At their first meeting, Roberta was rude and distant because she was high. Roberta tells Twyla she is on the way to see Jimi Hendrix. Hendrix was an infamous black guitarist. I thought at this point Roberta has to be black. However Hendrixs band was interracial wit h a diverse audience. Roberta could have been white due to the diverse audience. I am a huge Hendrix fan and I am not black so why would I phone Roberta is. Twelve years later they meet again at a grocery store.Roberta married a rich man and was extremely friendly to Twyla. Twyla cannot hold back her emotions and asks Roberta about the last time they motto each other. Roberta shrugs it off, Oh, Twyla, you know how it was in those days blackwhite. You know how everything was. I can relate to this. In 1980, the Cuban Mariel Boat Lifts came over bring thousands of Cubans. I am Cuban but I was natural here. Kids I had known since kindergarten treated me as if I just come over on the boats. It had a lasting effect on me and matured me beyond my years.The third time they meet is at the enlighten where their children attend. Roberta and other mothers were picketing because they did not want their kids to be segregated. This led to a fight severing any last chance of a friendship for t hem as it would not be resolved until Twyla and Roberta meet for a closing time. As the story ends I do not get a sense of closure. The question of which girl is white or black remains unanswered. It opened my eyes and made me question how prejudice I really am.I try to not stereotype as a result of what I went through as a child but I found myself doing just that. I can examine why Morrison wrote the way she. I am not sure what her goal was overall but to me it seemed as if she were teaching me about prejudices. Recitatif challenged me to not judge either girl by their race but deliver them for who they are. In the end, what difference did it really make about the girls races? The story is about how their friendship develops and then deteriorates. zipper more nothing less.

The old Nurses story Essay Example for Free

The old Nurses taradiddle Essaynot to mention that it had a forbidden area called the east wing, which was never opened. People never dreamt of going in that respect. and then we have the darkness pop out thither, this story is ground in a truly similar way. It is based in a house, which is at the end of a forbidden wood called Packers End. This area was scary. You didnt go there by yourself, not even for a thousand pounds. It was nasty, creepy. People were scared stiff of Packers End. When children were younger they believed that witches, wolves and tigers existed there.That was until they make up out about the German plane that had came down after the war, and an aircrew was killed there, people had heard them talking, dormant chattering in German. At the end of Packers End, there is a cottage, Mrs Rutters cottage. Both stories are narrated to young children by old female characters. The Old Nurses degree, is narrated by a nanny, and is told to the children, whic h she looks after. She seems to know a lot about the family history. thusly not only does she share her story with the children to inform them about their family, but in addition to entertain them.The phantasm fall out There, is narrated by a old cottage loaf women, who seemed composed of circles, a creamy mirthful pool of a face, and eyes which snap and dart. Already we can judge Mrs Rutters character, we are made to sapidity that this woman is not as nice as she seems. She seems snidy, and in truth crafty. We can sense darkness, this is very symbolismic. It connects to the designation and we soon realise why. As the plot begins to unravel, we begin to see the darkness in Mrs Rutter, the narrator of the story. It is also narrated to young children.Both stories have used children for they are innocent, and easily influenced. This creates sympathy, yet suspense. Scary noises are very important conventions, probably one of the most important, and they are also used in both(pr enominal) stories. In The Old Nurses Story, a great organ is heard playing, near the east wing. This was once played there by the late Lord Furnivall. In The Darkness unwrap There, airmen, witches, and wolves were said to be heard in Packers End. The noises create a tense atmosphere and suspense. We begin to feel scared, worried and wonder what is about to occur.It has a huge impact on the audience. The final similarity that I found interesting was that in both stories, the actions are influenced by death. In The Old Nurses Story, Lord Funivall, and Miss Furnivall both die. They are the ones that are luring their daughter Miss Rosamond to her death. In The Darkness Out There, Mrs Rutters husband is killed in the war. Therefore she refuses to help a German (enemies during the war) survive instead she leaves him to die. Although both stories have many similarities, they also have many deflexions.The most unmistakable difference is that both stories are written in different time zo nes. The Darkness Out There is a contempary story. It was published post world war two, whereas The Old Nurses story was written in the nineteenth century, therefore they do have different writing styles. Nevertheless we cannot judge the stiffness of the stories by clear-sighted when they were written. We need to know the context and its conventions. However we can judge by looking at the chief(prenominal) differences how and why a story is effective, and which particular ingredients make it effective.Firstly I looked at the aspect of worry in both stories. In The Old Nurses Story, weirdos are visual and non visual by dint ofout the story. This is a an transparent ghost story, it is very effective, and would have been more effective at the time it was published, for ghosts were believed in and had huge impacts on life. They werent just fantasies as people regard them today. In The Darkness Out There, although there are myths of ghosts and witches, the story isnt based on a gh ost. The only real fear is the evil darkness we find in Mrs Rutter. I also noticed that both stories are set in different types of weather.The Darkness Out There is based in summery weather there is no sign of mysteriousness apart from what had antecedently happened in Packers End. Although we do have a little bad weather, heavy rain, evil is not symbolised through the weather. The Old Nurses Story, however has bad weather, it contains dark dull, stormy weather. A terrible winter. This is a typical symbol of evil and strange occurrences. Bad weather represents evil and makes everyone miserable. It builds a lot of tension and suspense. The final difference is the difference we learn about the storytellers.Although they are both old and female, what we do not realise are the hidden connotations, for both storytellers have different intentions. Soon we understand that Hester, the narrator in The Old Nurses Story is not telling the children the story with the intention to scare, but is informing them about their family. Mrs Rutter, narrator in The Darkness Out There, is totally different. She is very ill minded, she tells the children the story to scare them so that she can gain pleasure by watching them terrified. In other words, she scares children for pleasure. I speculate The Old Nurses Story is the most effective story.Although it contains all the typical ingredients, it does scare. The setting, weather symbolism and usage of ghosts combined together make it a very effective ghost story. It creates tension, suspension, and a startled atmosphere. It also leaves the audience intensified. I didnt think The Darkness Out There was a very effective ghost story. To be honest it doesnt even seem equivalent a ghost story. Ghost stories are supposed to contain mysterious events, ghosts, and supernatural occurrences. The Darkness Out There doesnt scare the audience it just leaves them with a moral.That is never to stereotype people. It doesnt scare. I think ghost sto ries are effective because of the typical ingredients that they contain. A ghost story isnt a story without spooky occurrences. The subject of listening to a ghost story is to be scared. The Old Nurses Story creates this effect, and therefore I think it is the most effective. Show preview only The above preview is unformatted text This student written division of work is one of many that can be found in our GCSE Joseph Conrad section.

Those Most Nearly Touched Essay Example for Free

Those Most some Touched EssayOne of the most influential critics of the societal problems in American hi twaddle was complaisant Rights spokesperson W. E. B. DuBois, who believed that Honest and earnest unfavorable judgment from those whose interests are most nearly touchedcriticism of writers by readers, of government by those governed, of leaders by those ledthis is the soul of democracy and the safeguard of modern society. One of the leading vehicles of such criticism since the beginning of the United States of America was books. Like Harriet Beecher Stowes Uncle Toms Cabin, American literature molded its history by changing social perspectives with authors voices.Stowes character changed popular American societys views on the goodity of permanent servitude, and other writers have introduced unexampled views into mainstream thought by providing social criticism of their contemporariess through characters perspectives. Three such writers were Stephen Crane, Flannery OConnor, and Hunter S. Thompson. Cranes criticism of the nature of war, OConnors criticism of g residuumer, racism and religion, and Thompsons criticism of the deterioration of American values were all voices of American generations and essential elements of the organic evolution of modern American society.Stephen Cranes The Red mark of Courage was a novel that exploited an underlying mockery of the nature of the American Civil contend and war itself, as it was the first non-romantic novel of the Civil War to attain widespread popularity. Rather than depicting soldiers fighting for some noble and important ca call, care literature of the American Revolution, Crane painted what seemed to be loosely cohering incidents that demystified and reshaped his generations views on warfare. War was not dignified it was embarrassing stuff.Men ran away howling. Bodies were strewn and torn. War, went the cliche, was hell. Crane created characters and scenes that highlighted the problems of his Americas popular opinion of war for those whose interests are most nearly touched. In Cranes novel, those people were the innocent young soldiers who were thrown into hell and bestowed with responsibilities and expectations of highly immoral standards. He showed his generation and generations of Americans to screw the horrors and the true nature of war.By exposing the fears and inner thoughts of Henry Fleming in his new environments, Crane introduced America to the unpleasant reality that the blue and the gray honestly dont ever seem too entirely certain why theyre fighting each other. These were merely young men killing each other without really intellectual the reason. Crane allowed America to understand the point of view of an innocent thrown into chaos. By doing so, he changed the antecedently romantic, chivalrous perception of war, and altered it into modern societys idea of war and appreciation of peace.The short stories of Flannery OConnor were also vehicles for s ocial criticism of some problems of her generation, such as gender roles, sin, and racial relations. OConnors stories, written in the late forties and 1950s, were hard-hitting writings with a sense of deep despair as to the condition of the society that they described. She horridly illustrated the pre-Civil Rights racism problems present in her story Everything that Rises Must Converge. The story, which described a conflict of interest betwixt Julian and his racist mother on a newly de-segregated bus, allowed its reader to realize in the end that both characters were wrong.The mother was ignorant for being racist and living in her own perfect populace of sacrifice, while Julian was ignorant for blaming his mother for his place in life and for seeming to only pass water the side of the black people in the story just to prove her ignorance. In this sense, the ignorance in the story was met with a dose of poetic justice. Julians mother died, while he will be guilty for the oddmen t of his unhappy life. Another element of her society that OConnor criticized with her literature was its lack of true religious virtue and moral substance.She used multiple Christian elements to ironically sustain internally conflicting characters like Julian, blood-red in Revelation, and Parker in Parkers Back. Religious symbolism pervaded OConnors stories, like the hot breath of the burning tree that Parker met after his tractor accident, which was like the bush that Moses found. The tattoos that adorn Parkers body were absolutely symbolical of OConnors idea of her Americas moral fiber, like the tattoo of saviour Christ on his back, where he would never see it. The tattoo of a serpent evoked thoughts of the hellion in the Garden of Eden.OConnor frequently made use of the religious epiphany, or revelation, in her stories. In Revelation, Ruby experienced an epiphany at the end in the pig parlor as a result of the events that occurred in the doctors office with Mary Grace. Ruby w itnessed A visionary light in her eyes she saw the mottle as a vast swinging bridge extending upward from the earth through a empyrean of living fire. Upon it a vaste horde of souls were running towards heaven. In Parkers Back, Parkers conversion was one element of revelation in the story, but the real revelation occurred outside the bar in the alley when Parker contemplated his life.In The Lame Shall participate First, Nortons father experiences a horrific revelation when he entered the attic at the conclusion of the story. He agnise that he had stuffed his own emptiness with good works like a glutton, and had completely ignored the stirred needs of his own son. This fickleness and moral ignorance indicated a strong lack of true religious faith present in her society. Perhaps OConnors greatest legacy to the world of literature and social commentary was her component part to the widespread perception of gender roles in her American society.Stories like The Life You Save May Be Your Own gave a generation of readers a new perspective on life as a woman in rural America. The grotesque nature of it and OConnors other stories made the message that she conveyed to society peculiarly sharp-edged. Her criticisms of her societys problems with gender and race relations, and the value of religion, were pungent and effective vehicles of change that molded American mindset in more ways than one. The late Hunter S. Thompson was a third American author that affected a generation with his ? no holds barred journalistic approach to fiction and social criticism.Thompsons underlying criticism was oftentimes like Cranes a century earlier. Thompson wondered the point in fighting -on our side or theirs, a vox populi common of to his generation that would not have manifested if Cranes ideas had not. Thompson also criticized the counter-culture created by the Peace and Understanding attained by the chaotic ? baby-boomer rebellion that began in the 1950s and crested in the 1960s. He was not opposed to the increasingly common use of mind-altering drugs as much as he was disappointed in his societys disaster to sustain the peace and understanding.Thompson notes, Their loss and failure is ours, too. What (Timothy) Leary took down with him was the central illusion of a whole life style that he helped to create a generation of permanent cripples, and failed seekers. By criticizing the drug culture as a user, Thompson embodied the hypocrisy of the generation that he portrayed. Perhaps he represented drug use as getting rid of the pain of being a man just as well as Richard Nixon represented ? that dark venal, and incurably violent side of the American character. One thing was for certain, that Thompson embodied the changing moral aptitude of America.His society liberalized taboo or immoral topics into mainstream culture like the widespread use of drugs and sex. The proponents of these changes were names such as Hugh Hefner, Larry Flynt, Cheech and Cho ng, and Tim Leary. To many, these values, or loss thereof, represented a loss that Thompson termed more resolutely as the death of the American Dream. Neither peace nor morality was prevalent in Thompsons era or modern Americas. In this sense, Thompson merely chronicles the changes as he claimed, as a ? gonzo journalist.However, his descriptions were certainly eloquent and meaningful enough to open the eyes of generations following to the realities and perspectives that occurred in the midst of the chaos of his generation. Stephen Crane, Flannery OConnor, and Hunter S. Thompson were three American authors who significantly altered the course of American history with the social criticism present in the perspectives of characters in their literature. Whether the heart of their intended critique on society was gender, religion, race, or war, these writers molded their respective generations and subsequent generation with their voices.They each contributed to the American society that they criticized with their criticism, the soul of democracy and the safeguard of modern society. Works Cited Crane, Stephen. The Red Badge of Courage. New York The Modern Library, 1951. OConnor, Flannery. The Complete Stories. New York Farrar, Straus, and Giroux, 1971. Thompson, Hunter S. Fear and Loathing in Las Vegas. New York stochastic House, 1971. Schwartz, Stephen. The End Of The Counter-Culture. The Weekly Standard, 22 February 2005. Davidson, Andy. University of Mississippi English 224 Angel Online class notes.

Spontaneous Recovery and Extinction Essay Example for Free

self-generated Reco re altogethery and Extinction EssaySpontaneous recuperation from liquidation is one of the just about basic phenomena of Pavlovian conditioning. Although it give nonice be studied by using a revolution of bods, close towhat turns ar better than others for identifying the involvement of lowlying discipline dish outes. A wide range of varied culture utensils has been suggested as being engaged by quenching, most of which set about implications for the character of natural recuperation. However, notwithstanding the centrality of the feeling of impulsive rec everyplacey to the go steadying of experimental extinguishing, the semiempirical literature on its determinants is congenericly sparse and quite mixed. Its very ubiquity suggests that self-produced recuperation has multiple sources.Previous varianceNext SectionExperimental defunctness is one of the sound observations of Pavlovian conditioning. Just as the arranging of a pos itive relation in the midst of a learn arousal (CS) and an unconditioned foreplay (US) produces accomplishment of conditioned responding, breaking that relation produces extermination of that responding. However, similar to more than terms in the demeanoral sciences, the word extinguishing is used in at least triple resistance senses as a subprogram, as a result, and as an explanation. If we ar to deduct extermination experiments, it is super grave that we keep these senses distinct from each other. One use of the term is as an experimental procedure or independent variable under the control of the experimenter, as when one says, Following eruditeness, we subjected the animal to an extinction procedure. Most frequently, this is meant to refer to a procedure in which the real conditions of tuition are disrupted. The most normal extinction procedure consists of presenting a stimulus alone, so that it now fails to signal the outlet.However, other procedures, suc h as retaining the US provided arranging for it to be independent of the CS are in two eccentric person available and of use up (see Rescorla 2001a). Another use of the term is as an experimental result or dependent variable under the control of the animal, as when one says, When the stimulus was presented alone, the conduct extinguish. The prototypical example is one in which responding that was establish by fosterage deteriorates, often to a level such as that preliminary to learning. A deuce-ace use of the term extinction is as a act upon orintervening variable that is think to provide an explanation, as when one says, When we arranged for the stimulus to be presented alone, the behavior deteriorated because of extinction. Normally, it is this process that is of interest. We would homogeneous to understand the basis of the pitch in behavior resulting from the change in procedure, whether that understanding is achieved at a abstract or a neural level. Consequently , throughout this article the term extinction depart refer to the learning process opinered when the procedure produces a incident result.When thither is the possibility of misunderstanding, the phrase extinction process provide be used. Because interest primarily centers on the learning process that occurs as a result of an extinction procedure, it is important to separate that learning from a wide variety of other substances that govern consummation. The let go of here is analogous to that of understanding the learning that occurs during an encyclopedism procedure. Elsewhere we encounter argued that the measurement of learning demands direction to 2 points in prison term t1, during which the opportunity to learn is given, and indeed a separate t2, during which an judicial decision is do of that learning (see Rescorla and Holland 1976 Rescorla 1988). The semblance that indicates that learning has occurred is that amid two animals (or two stimuli or receptions) gi ven a command t2 render following antithetical opportunities for learning at t1.This comparison is superior to the contingent(a) K selection of examining responding during t1, at which the animals are receiving incompatible learning give-and-takes. Data taken during t1 inevitably confound the expirations in the underway dowery under which learning is assessed with take issueences in the learning that prior treatments qualification carry produced. We have argued that for this reason acquisition curves are in purget deeply flawed as a way to measure learning. A similar point applies to the learning that occurs in extinction. In this theme, we invite to administer a common turn out for stimuli or animals given resistent extinction experiences, as indicated in the depression portion of Figure 1.In the simplest case, we john compare responding to two stimuli (S1 and S2) at a common t2 by and by both have had the aforesaid(prenominal) initial acquisition just t hen differ in whether or not they were given extinction at t1. Differences in t2 test slaying would then index the differences in learning that occurred at t1. Clearly, comparisons betwixt stimuli during the t1 extinction experience are of limited value because any differences competency bethe product of the current conditions of examen rather than of the retentiveness for the learning that has occurred. That is, extinction curves are of very limited use in understanding the be process. Figure 1View larger versionIn this pageIn a new-made windowDownload as PowerPoint SlideFigure 1Experimental designs for the bailiwick of extinction and impulsive convalescence. (A) A recommended procedure for studying extinction, in which the life-sustaining comparison is responding to S1 and S2 at a common test clip when the two stimuli differ in their extinction invoice. (B) The design in which unwritten recuperation is near sentences inferred from the great responding to S1 duri ng test than during extinction. (C) A better self-produced retrieval design in which S1 and S2 are both deft and extinction, only then tested for recovery afterwards different time periods. (D) An alternative design in which S1 and S2 are tested in a common test session, despite different times mingled with extinction and test. In this scope, the phenomenon of off-the-cuff recovery has a complex role. That phenomenon suggests that the results that we detect in a t2 assessment may be quite different depending on the length of time that intervenes between the t1 extinction experience and the t2 test.It has been known since Pavlovs (1927) early experiments that the prejudice of behavior that results from presenting the stimulus alone at t1 is not entirely permanent. blacklegher, with the portrayal of time following non reinforcing stimulus, in that respect is some instinctive recovery of the initially learned behavior. Introducing greater time delays between t1 extinct ion treatment and t2 test provides the opportunity for greater unwritten recovery. At minimum, the phenomenon of instinctive recovery provides some information about what process fails to business relationship for the damage of behavior when an extinction procedure is conducted. It suggests that the loss does not simply involve the removal of what was learned in acquisition. As Pavlov noted, if an extinction procedure had erased the acquisition learning, then there would be no basis for behavior to think with time.It suggests that instead something happens during the extinction procedure that temporarilysuppresses achievement while leaving some of the initial learning in place. Of eat, the finding of impulsive recovery does not imply that there is no removal of the initial learning or until now that there was any learning during extinction. It provided implies that some of the initial learning survives an extinction procedure. The finding of free recovery may in addition be taken as providing some information on the nature of the processes that suppress behavior. If one believes, as Pavlov did, that the return of behavior after non keep going represents the loss of a learning process that occurred during the extinction procedure, it suggests that this learning is malleable, changing with time.That is, it suggests that one property of the extinction mechanism is its relatively lower st business leader with time. For both of these reasons, many have hoped to learn something about the processes underlying movement loss in extinction by an probe of unprompted recovery. Although there have been substantial advances in the neurobiological study of extinction in the travel few years (for reviews, see Myers and Davis 2002 Delamater 2004), almost all studies of unprompted recovery have been at the purely behavioral level. Consequently, the word of honor that follows go forth focus merely on such behavioral studies.Previous SectionNext SectionDesign s for Studying Spontaneous convalescenceThe standard description of unprompted recovery is that the responding that was depressed during an extinction session is partly restored in a test session that is administered after a delay. As illustrated at the second panel of Figure 1, unbidden recovery is comm sole(prenominal) inferred from a comparison between responding at the end of an extinction session and at the beginning of a test. great response in the test is taken to mean that some portion of the initial learning survived the extinction. unvoiced in this interpretation is the assumption (1) that the behavior that starts on the early trials of the test session is attributable to the original learning rather than to something else, and (2) that the increase between the extinction and the test represents a reduction in the effect of the learning that occurred in extinction. To justify the first gear assumption, comparison really should be made between responding to an snuff out stimulus and responding to one that has never been trained prior to extinction but is still given the alike(p) detachment between extinction and test sessions in which to recover.Otherwise, it is possible that the increase in responding represents a general tendency to increase responding with time independently of the original acquisition that is, it king not reflect recovery of the initial learning at all. In position, there are only a few studies (see Robbins 1990) that have deliberately made such a comparison. But any detai direct investigation of involuntary recovery should be sensitive to this possibility. To justify the second assumption (that the increase in responding represents dissipation of the extinction learning), comparison should be made with a stimulus that has trained, but not been extinguished, and that paint a pictures responding at a level corresponding to that of the extinguished stimulus in the beginning the delay interval. For instance, one energy compare, for the equivalent animal, changes with time in a trained and extinguished stimulus and a stimulus that is only partially trained, so as to fulfill the like response level. It is only if the former stimulus shows greater growth with time that one would fold that there is a loss of the learning that occurred during extinction, as distinct from a general change in performance for any previously trained stimulus showing behavior at that level.A emplacement from the need to occasionally include these comparisons, the spontaneous recovery design shown in Figure 1B has the drawback of repeat interrogatory with the same stimulus, with the consequence that different summates of extinction trials have necessarily preceded the trials being compared. A better design, which is likewise frequently used, is shown in Figure 1C. In that design two stimuli are both trained and extinguished but then given different amounts of time to recovery prior to the test. This design avoids re peated testing on the same stimulus and has the return of an explicit test session. But unfortunately, the tests of the two stimuli differ not only in the time since extinction but also in the time since original cookery and in the overall test condition and age of the animal. To avoid these confoundings, we have frequently adopted a somewhat different design for studying spontaneous recovery, as illustrated in Figure 1D. In this comparison, two groups of animals receive conditioning followed by extinction and a test. The groups differ in the placement of the extinction with pick up to the test. For one group (S1) the extinction occurs at a worldly distance from the test, so as to conquer spontaneous recovery.For the other group (S2), extinction occurs right off prior to test, minimizing recovery. The severalize for recovery is then the difference in responding at the time of the common test. That allows comparison of responding during the same test session, after the same s ubdue of extinction trials, to stimuli that share the time since original knowledge but differ in the time since their extinction. The design erect be further strengthened if the two stimuli are both trained in the same animal. An especially important advantage of such a within-subject comparison between S1 and S2 is that it involves a common test session in the same animal. This means that any recovery supportnot be attributed to general changes in the animals deposit or to derivative instrument similarity of the test conditions to those of original training. One difficulty with the standard procedure for assessing spontaneous recovery is that one part of the comparison comes from a session in which the animal is undergoing an extinction procedure and is therefore likely to be experiencing a variety of new stimulus events that may have heterogeneous emotional consequences.The presence of those new events could, in themselves, artificially depress responding to a lower level t han that which is warranted by the learning that is occurring. The likely absence of those stimuli at the beginning of the test session could allow greater responding for reasons that are not central to the learning that is occurring in extinction. But the final design avoids such differences in the context of performance for the stimuli being compared. By using within-subject versions of this last procedure, Rescorla (1997a,b) has shown evidence of substantial spontaneous recovery in a variety of conditioning preparations. An example is shown in Figure 2 for a Pavlovian clip approach situation with rats. In this preparation, S1 and S2 are counterbalanced as a 30-sec send and noise, each opposite with the delivery of food and then given nonreinforcement. The result is an increase and decrease in anticipatory responding involving investigation of the food delivery site, the magazine. A test then takes place every immediately after the last extinction session or after a delay. The c omparison of interest is that between S1 and S2 in the common test session. Figure 2 distinctly indicates greater recovery for the stimulus extinguished first, S1. One may note that S1 also shows more responding in the test than it did at the end of extinction but as noted above, this comparison is flawed. Figure 2View larger versionIn this pageIn a new windowDownload as PowerPoint SlideFigure 2An illustration of spontaneous recovery using the design shown in Figure 1D. Rat subjects were given Pavlovian magazine-approach training and extinction with two stimuli, S1 and S2, and then tested in a common session. The superior responding in S1, compared with S2, is used to infer spontaneous recovery. Of itinerary, no procedure is without its shortcomings. In this alternative procedure for assessing spontaneous recovery, one of the stimuli must necessarily be extinguished before the other. Consequently, the narrate in which the stimuli are extinguished, and the interval between trainin g and test, are both confounded with the interval of interest, between extinction and test. Although application of the design has not revealed any resulting differences in the course of extinction itself (Fig. 2), one must still be cautious about the implications of such a confounding. Consequently, it may be most wise to use both procedures C and D in any research program investigating spontaneous recovery. Previous SectionNext SectionBases for Spontaneous RecoverySpontaneous recovery is such a widespread phenomenon, both in terms of the variety of learning paradigms in which it occurs and the frequency with which it is report, that it would be affect if it had only one source. Indeed, many different sources have been suggested, most of which have received some empirical support. But not all of these are of equal interest in helping us understand the learning involved in extinction. Here, I attempt a rough categorization of those sources. Local accomplishment EffectsAs noted abo ve, when one makes the standard comparison of responding on the final trials from extinction with that on the initial trials in a test session, one can expect that they will differ in a number of ways unrelated to the learning that occurs in extinction. For instance, the repeated evocation of a conditioned response might lead to temporary have on that adds to the loss of behavior.It is not uncommon to see behavior decay over the course of a conditioning sessioneven when reinforcement continues (see McSweeney and Swindell 1999). Similarly, the surprise deletion of forecastd reinforcement may well lead to emotional responses that have a disruptive effect on performance. For instance, the surprising omission of food can be expected to lead to frustration, which changes the stimulus environment and may evoke responses of its own (see Amsel 1958). Effects such as these might well be expected to dissipate before the beginning of the test session, hence revealing any incompleteness of t he extinction process that they masked at the end of the extinction session. Although such effectuate may contribute to the deterioration of performance during the administration of an extinction procedure, they may have little to do with any underlying learning process. If spontaneous recovery could be measureed for solely on the basis of such effects, it would be of substantially less(prenominal) interest.Contributors of this sort to response suppression seem especially likely to affect the standard spontaneous recovery designs that compare responding to the same stimulus in two different sessions. They are less likely to contribute to recovery when it is measured as the difference in responding to two stimuli during the same test session. Indeed, part of the motivation for developing the alternative assessment of spontaneous recovery (D) was to reduce the various general differences that are confounded when responding in two different sessions is compared. Spontaneous Recovery Despite Loss of Acquisition LearningDespite the widespread agreement that spontaneous recovery indicates that the original extinction process does not involve the erasure of the original learning, there have been some attempts to defend an erasure theory and still explain recovery. Perhaps the most well known attempt is the innuendo by Skinner (1938) that an extended extinction session leaves the stimuli from the beginning of the session incompletely extinguished.Consequently, those stimuli still have some strength that can be exhibited at the beginning of the next session. Skinner seems to have believed that extinction eventually removes all of the original learning but initially leaves the session-beginning stimuli partially effective, thereby explaining spontaneous recovery. Although there is some evidence that stimuli that are explicitly presented by the experimenter at the start of a session can retain some strength when extinction takes place in their absence (see Burstein and Moeser 1971), it seems unlikely that this will to the full accountfor spontaneous recovery. Several experiments have found evidence of strong spontaneous recovery even when the session starting stimuli are well controlled (see Thomas and Sherman 1986) or when an extinguished stimulus is tested in the middle of a session only after another stimulus has completely lost its spontaneous recovery (see Robbins 1990). Moreover, it is hard to see why this account would anticipate one of the basic findings of spontaneous recovery, that it increases with the handing over of time.A somewhat more successful version of such an account was offered by Estes (1955) as a component of his influential stimulus sampling theory. Estes argued that what experimenters identify as stimuli can actually be viewed as constructed of many elements with occurrence that fluctuates in time. Acquisition and extinction produce changes in the connexions between the outcomes and those elements over the course o f trials. According to that theory, when an element is paired with a reinforcer, it immediately becomes fully conditioned when it is presented without reinforcement, it immediately reverts to its unconditioned state. It is only the random fluctuation in the selection of elements over trials that gives the normally observed gradualness to changes in behavior.At heart, this is a theory in which extinction involves the actual erasure of learning. The important point to notice is that when trials are given in close proximity, they tend to share more elements when trials are separated, then they sample different elements from the pool that constitutes a given stimulus. Consequently, with repeated extinction trials, performance can decrease even though some unsampled elements remain conditioned. With the passing play of time, the likelihood of sampling those nonextinguished elements can increase, generating spontaneous recovery. Like the account offered by Skinner, this account correctly predicts that repeated extinction will mitigate spontaneous recovery. Unlike that account, it gives no special role to session-initiating stimuli, and it can account for the growth in recovery with time. The stimulus sampling theory also correctly anticipates the occurrence of spontaneous recovery with all of the various assessment procedures.These successes demonstrate that one can account for at least some of the basic facts about spontaneous recovery even on the assumption that the extinction process involves (partial) removal of the original learning. They also highlight the fact that the observation of spontaneousrecovery does not imply that extinction must leave all of original acquisition in place. Spontaneous Recovery as an Indication That Extinction Involves Inhibition If one envisions an extinction procedure as leaving intact even a portion of the original learning, then it is natural to conclude that some new learning is occurring that is superimposed on acquisition and prevents performance. The classic candidate for such new learning has been stifling. A wide variety of different miscellaneas of ban have been proposed, suggesting quite different ideas about the nature of extinction. But in each case, spontaneous recovery is accounted for by the dissipation of that inhibition with the passage of time.CS-Based InhibitionPavlov (1927) was the first to suggest that extinction involves inhibition and that spontaneous recovery is an indication that this was so. He viewed the learned inhibition that he supposed to occur during extinction as more vulnerable than the excitation that develops in acquisition to such intrusions as the presentation of a new stimulus (i.e., disinhibition) and the passage of time (i.e., spontaneous recovery). Although it is not widely appreciated, Pavlovs notion of inhibition was highly focused on the CS and was envisioned to develop independently of whether or not the reinforcer occurred. Pavlov believed that every CS pres entation leads to the building up of a kind of fatigue in the neural cells stimulated by that CS, whether or not the reinforcer followed. This leads to a reduced capability of the CS to stimulate its neural targets, which would in turn lead to reduced behavior.That is, the natural consequence of repeatedly presenting the CS is a deterioration of behavior. However, during acquisition, this process is overwhelmed by the growth of an association which the CS develops with the reinforcer. With rest, the CS-based inhibition fades and responding can recover. Robbins (1990) proposed a related notion of inhibition, which he described in terms of reduced attention to the CS. He suggested that during acquisition, attention to the CS grows whereas during extinction it falls. Part of the reason for the decline of behavior in extinction is then reduced attention to the CS with the attendant loss in its ability to evoke responding. With rest, that attention partially returns. Unlike Pavlov, Robb ins envisioned the effectiveness of the CS as dependent on the trial consequence, growing with reinforcement and declining with nonreinforcement. In support of this view,Robbins (1990) found evidence, in a sign-tracking preparation with pigeons, that a CS lost its ability to serve a variety of different functions during an extinction procedure but then recovered them with time. He trained a CS simultaneously to have an excitatory association with a US and also to serve as a conditional signal that another CS would not be followed by a US.When he extinguished the excitatory association, the CS lost both properties and then regained them both with the passage of time. That result is consistent with the view that one contributor to the loss of behavior with extinction and its restoration with time may be changes in the processing of the CS per se. On the other hand, both Bouton and Peck (1992) and Rescorla (1997a) have found evidence for spontaneous recovery following counter-condition ing in which one US is replaced with another. Because counter-conditioning chip ins a CS that continues to produce some behavior, those cases of spontaneous recovery seem unlikely to be attributable to loss and recovery of the processing of the CS. Of course, the processes underlying spontaneous recovery after such procedures may differ from those underlying the changes after extinction. Response-Based InhibitionShortly after Pavlovs work became available in this country, Hull (1943) suggested a similar account of extinction and spontaneous recovery that focused on the response rather than on the stimulus.As part of a multiprocess account of extinction, Hull argued that each occurrence of a response leads to the building up of a fatigue-like process that is specialized to that response and that reduces its subsequent likelihood of occurrence. This process contributes to the decrease in performance during extinction but dissipates with time, permitting spontaneous recovery. Similar to Pavlov, Hull seems to have believed that the changes in this response-fatigue are independent of reinforcement contingencies indeed, he believed it left no permanent learning impact at all. That is, this particular repressive notion is more akin to the performance effects discussed above. It has proven difficult to confirm the most obvious implication of such an approach, that the effortfulness of the response should deflect the course of extinction and spontaneous recovery (see Mackintosh 1974). But, one advantage that can be claimed for the alternative test of spontaneous recovery described above is that it provides a common test session in which all stimuli should share any general fatigue processes.Outcome-Based InhibitionOne way of viewingextinction is that a CS that was once followed by an effective outcome is now followed by an ineffective one. Indeed, there is evidence that if the outcome potency is deliberately partially reduced, then behavior partially deteriorates (s ee Wagner and Rescorla 1972 Kehoe and White 2002). This suggests the possibility that one change that occurs in extinction involves a reduction in the memory of the outcome itself. Based on this kind of thinking, Rescorla and his collaborators (see Rescorla and Heth 1975 Rescorla and Cunningham 1978) suggested that one process that occurs in an extinction procedure is a depression in what they called the US representation. This led them to explore manipulations that might affect the state of the US representation independently of its association with a particular CS. By using a fear conditioning preparation in rats, they documented the phenomenon of reinstatement first inform by Pavlov, that responding could be restored to an extinguished CS by separate presentations of the US alone.Although others (see Bouton 1984) have given different accounts, Rescorla and Cunningham described this manipulation as restoring a portion of the extinction-depressed US representation. They also argue d that there might be a recovery in the US representation with time, leading to the phenomenon of spontaneous recovery of responding to the CS. In support of that possibility they found that, under some circumstances, recovery could be undermined by the nonreinforcement of another CS immediately prior to testing, a manipulation presumed to reduce the US representation. However, various other implications of this notion have not received support. For instance, Robbins (1990) found evidence of independence in spontaneous recovery for two stimuli that had been conditioned with the same US. Moreover, Tomie et al. (1980) reported spontaneous recovery after an extinction procedure in which the US was continued but made independent of the CS, a procedure that should maintain the US representation.Nevertheless, it is possible that changes in the memory for the US may make a contribution to spontaneous recovery in some preparations. Associative InhibitionMost coetaneous views of Pavlovian i nhibition involve not individual events but rather associations between events. For instance, Konorski (1948) argued that a variety of conditioning paradigms, including extinction, lead to the development of an repressive association between the CS and US that is parallel to, but the opposite of, the excitatoryassociations set up during acquisition. In later writings, Konorski (1967) offered a somewhat different account, concord to which restrictive learning involves associations between the CS and a consequence that is the opposite of the US, the no US.Most contemporary discussions of Pavlovian inhibition implicitly accept one or the other of these views. The standard ways of detect such associable inhibition are to ask whether an inhibitory stimulus can reduce responding to an other than effective excitor (a summation test) or is slow to acquire excitation if it now receives an excitatory training treatment (a retardation test Rescorla 1969). Most contemporary evidence suggest s that an extinguished stimulus does not in fact demonstrate net inhibition with either of these tests. presumptively this is because the inhibition that builds up during nonreinforcement is only just commensurate to counteract the original excitation, but does not develop beyond that level so as to convey a net inhibitory stimulus. However, there is some evidence that an originally neutral stimulus that accompanies an excitatory CS during an extinction procedure does capture inhibition, as assessed by these tests (see Rescorla 1979, 1999). Moreover, there are some reports (see Henderson 1978) that a net inhibitory stimulus does lose some of its inhibitory properties with the passage of time, in the way require if this were to contribute to spontaneous recovery.An alternative associative basis for extinction has been proposed by Colwill (1991) and explored by Rescorla (1993). According to that account, the inhibition that develops during extinction involves associations between the stimulus and a response. These inhibitory S-R associations are envisioned as existing side by side with excitatory associations that involve the US. Consistent with this view (but not with the notion of inhibition between the CS and US), Rescorla (2001b) used outcome- particularised transfer procedures to reveal that the CS-US associations maintained their full net strength after extinction, despite the reduction in responding. Moreover, he found no evidence that those CS-US associations changed in the way expected with the passage of time if they were to be the basis of spontaneous recovery. He proposed instead that extinction can involve an associative response-specific process that depresses responding but deteriorates with time.An alternative view of Pavlovian conditioned inhibition in terms of pitch contour has received substantial recent attention. Several investigators (see Holland 1983,Rescorla 1985) have suggested that under some circumstances an inhibitory stimulus do es not develop an association with a separate event, such as US or a response, but rather acquires the ability to control the strength of an excitatory CS-US association. This type of inhibition is not the opposite of an excitatory association but rather plays more of a hierarchical role, modulating a CS-US association. Bouton (1991) has suggested that both contextual and temporal stimuli can serve this modulatory role for a stimulus subjected to an extinction procedure. During the extinction procedure, the excitatory association is seen as remaining intact but being disabled by the presence of contextual or temporal stimuli that had accompanied nonreinforcement.With a change in either the context or the temporal stimuli, this inhibitory process is attenuated, allowing the return of performance. The phenomenon of renewal provides evidence for this view. If, following extinction, the stimulus is tested in a different context, there can be a substantial recovery of responding (see Bou ton 1991). If one views the passage of time as analogous to changing the context, this view provides a way of conceptualizing spontaneous recovery. Differential RetrievalThe inhibitory accounts of extinction and spontaneous recovery all envision the strength of original learning as remaining unchanged throughout extinction and spontaneous recovery. They see the decrease in responding during extinction as attributable to the growth of the inhibitory process, and the increase in responding with spontaneous recovery as attributable to the dissipation of that inhibitory process. In effect, the memory for the extinction process loses strength with the passage of time. An alternative framework for understanding extinction and spontaneous recovery involves differential recovery of the acquisition and extinction experiences, both of which remain fully intact.For instance, beam (1971) and Bouton (1993) have both noted the formal analogy between interference paradigms as studied in humans an d the acquisition/extinction sequence of Pavlovian conditioning. In both cases, the organism is exposed to two competing pieces of information that might be expected to interfere with each other. This led both investigators to the proposal that differential performance might reflect differential likelihood of retrieving the two experiences, rather than a weakening of stored information about either experience. According to this view, manipulations that make theretrieval of one experience or the other more likely will result in changes in overall performance. For instance, a stimulus that accompanies extinction might serve as a retrieval cue, presentation of which would promote the retrieval of the memory for extinction. Evidence for such a process can be found in the ability of some such stimuli to diminish the order of magnitude of spontaneous recovery (see Brooks and Bouton 1993).A related view, focusing specifically on spontaneous recovery, is incorporated in Devenports (1998) te mporal weighting swayer. According to that rule, when an animal has multiple experiences with a stimulus prior to a test, it weights those experiences harmonize to the relative time that has passed between each and the test. In the case of acquisition followed by extinction, this means that performance will deteriorate under the currently experienced nonreinforced treatment. However, as time passes, the relative temporal advantage enjoyed by the recent nonreinforcement experience will diminish, leading to spontaneous recovery. On views such as these, there is a permanence for both the acquisition and extinction experiences what changes with time is their relative likelihood of retrieval.As this discussion indicates, a broad range of different processes have been envisioned as contributing to the decrement in performance resulting from an extinction procedure and to the recovery from that decrement with the passage of time. Moreover, one can identify evidence supporting each idea. I t seems likely that each of these may contribute to the changes in various situations. However, none of them seems comfortable to provide an account on its own. One challenge that each contributor faces is to provide an account of the present empirical determinants of spontaneous recovery. For this reason it is worth reviewing some of those determinants.Previous SectionNext SectionBasic Empirical PropertiesDespite the centrality of spontaneous recovery to the phenomenon of extinction, there is actually surprisingly little well-documented information on its detailed properties. However, quatern features of spontaneous recovery seem to be widely accepted. Spontaneous Recovery Increases in a Negatively speed up Fashion Over Time Almost every description of spontaneous recovery includes the claim that recovery is greater the greater the delay between extinction and test. Indeed, there is a sense in which greater recovery with more time is a defining property.Moreover, the form of th at increase appears to be negatively deepen. For instance, in recent years, negatively accelerated recovery has been found with eyelid conditioning in rabbits (Haberlandt et al.1978), sign-tracking in pigeons (Robbins 1990), and fear-conditioning in rats (Quirk 2002). Almost all of the potential contributors to recovery listed above appear to be consistent with such a pattern of change. Although the various inhibitory theories make no specific predictions about how that inhibition fades with time, the negatively accelerated nature of many biological processes makes the finding unsurprising.The stimulus sampling mechanism described by Estes (1955) and the differential weighting rule proposed by Devenport (1998) also yield this expectation. Perhaps the only potential contributor that does not anticipate this is Skinners (1938) suggestion that at the beginning of the session stimuli retain their ability to evoke a response. Spontaneous Recovery Is IncompleteAlthough Pavlov claimed to have observed full recovery from extinction, most other investigators have reported only partial recovery. Even when recovery of responding appears to be complete on the first test trial, the rapid loss of responding over the course of testing suggests that recovery was actually less than full (notice, for instance, the rapid loss during testing shown in Fig. 2).The incompleteness of recovery appears to be mandated by some of the mechanisms described above. For instance, the stimulus sampling account of Estes and the weighting rule of Devenport appear incapable of allowing the impact of extinction to disappear altogether. The other mechanisms are less well-specified in this regard. Spontaneous Recovery Declines With Repeated ExtinctionIt is widely agreed that the greater the amount of extinction, the less the magnitude of spontaneous recovery after any fixed waiting time.This most frequently shows up as the reduced amount of recovery from day to day over multiple days of extinction. An illustration of that decline is shown in Figure 3, which displays results from a recent magazine-approach study with rat subjects done in our laboratory. That figure shows responding during repeated daily extinction sessions in which a 30-sec noise was presented eight times without its food pellet. Another stimulus, a light, received intervening reinforced trials. It is clear that there is repeated recovery of responding that gets smaller over the course of extinction. Figure 3View larger versionIn this pageIn a new windowDownload as PowerPoint SlideFigure 3The decline in the magnitude of spontaneous recovery with repeated extinction. Rat subjects were given Pavlovian magazine-approach training with a noise and then repeated extinction sessions. Actually, in the absence of some better understanding of scaling issues, it is difficult to compare quantitatively the amounts of recovery for stimuli that have undergone different amounts of extinction. Clearly, if minimal extinction ha s occurred, there is less decrease in behavior and hence less opportunity for recovery to occur. Similarly, with massive extinction, performance may be at a floor, and hence, even substantial recovery may be difficult to detect. But most mechanisms of recovery appear to anticipate that the deeper the extinction the less the recovery. That prediction is obligatory for accounts of recovery such as that offered by Estes and by Devenport, who see repeated extinction as accumulating a relatively permanent depressive process.Data such as those shown in Figure 3 are commonly taken as consistent with this prediction. Spontaneous Recovery Can Be Brought Under Stimulus ControlThere is good evidence that the learning process that occurs during extinction can be brought under stimulus control. For instance, Rescorla (1979) reported that a stimulus present during the nonreinforcement of a previously trained excitor took on the properties of a conditioned inhibitor, suppressing responding to othe r excitors. Indeed, the so-called conditioned inhibition paradigm consists of little more than intermixing reinforced and nonreinforced presentations of a stimulus while signaling the nonreinforced presentations by a second stimulus. Similarly, Bouton (1991) has reported that if the context present during extinction is removed by testing in another context, then the suppressive effects of extinction are reduced and behavior is renewed.Brooks and Bouton (1993) have extended these observations to the responding observed in spontaneous recovery. They found (see also, Brooks 2000) that if an explicit stimulus is present during extinction of an excitor, then that stimulus has the ability to diminishspontaneous recovery if it is presented at the time of the test. Although few theories of extinction are challenged by the observation that whatsoever is occurring in extinction can be brought under the control of a stimulus, retrieval theories seem like the most natural account. For instance , Bouton has argued that a stimulus present during extinction is especially good at retrieving a memory for a CS-US association. There is now substantial evidence that one stimulus can be learned as a signal of the relation between another stimulus and the US (see Schmajuk and Holland 1998). much(prenominal) modulation or occasion setting could be the mechanism by which explicit stimuli, contexts, or even time, might activate the memory of a CS-US association (see Bouton 1991, 1993).Previous SectionNext SectionDeterminants Needing Further InvestigationIn addition to these four well-established findings, there are a variety of other manipulations that have been claimed to affect spontaneous recovery but for which there is substantially less or even contradictory evidence. This is unfortunate because the effects of many of these manipulations might be informative in identifying the contributions of particular mechanisms of recovery. The Symmetry of Spontaneous Recovery and Regression Accounts of spontaneous recovery differ in the degree to which they treat extinction as engaging a special learning process with distinctive properties, such as the likelihood of its memory fading in time. Beginning with Pavlovs, the various proposals of inhibitory processes have tended to see them as different from excitatory process precisely in their greater asymmetry with the passage of time. This is all the way true for the fatigue-like processes mentioned by Pavlov, Robbins, and Hull, but it also seems true of some associative inhibition accounts, such as those described by Rescorla and Bouton.By contrast, the stimulus sampling theory of Estes and accounts that greet to retrieval or relative weighting seem to make little distinction between acquisition and extinction processes in their inherent vulnerability to time. They see the animal as integrating two experiences that it receives sequentially in time in a similar way regardless of the identity of those processes. This m eans that the latter accounts anticipate that one should observe a companion phenomenon to spontaneous recovery from extinction if one were to interchange the order in which extinction and acquisition were administered.That is, they expect to see simple regression of responding after acquisition if that acquisition were preceded by some sort of nonrein-forced training. The evidence for such regression is highly mixed. Notice that the simple deterioration of performance from day to day during acquisition is not capable to identify regression that is the opposite of spontaneous recovery. The critical observation is that there is a deterioration in performance that is attributable to a prior history of nonreinforcement, just as the critical observation for spontaneous recovery is that there is an improvement with time that is specific to stimuli that have a history of reinforcement.When animals are given in sequence two reinforcement experiences that differ in reinforcer valence or f requency, there is evidence that regression in the direction of the first performance can be observed with time (see Bouton and Peck 1992 Mazur 1996). But the results are less clear when nonreinforcement of a stimulus precedes reinforcement prior to the waiting period. Some early experiments reported positive results (see Spear et al. 1965 Konorski 1967). But some more recent studies have found no evidence for regression or the opposite results (see Kraemer et al. 1991 Rescorla 2001b). Clearly it would be valuable to understand the circumstances under which one obtains either regression or its opposite if one is to evaluate the contributions of various mechanisms to spontaneous recovery. It will surely be important to distinguish among different kinds of nonreinforcement experience that might precede reinforcement.The simple exposure to a stimulus prior to any reinforcement is certain to endow it with properties different from those of a stimulus that signals nonreinforcement explic itly, as in the case of conditioned inhibition training or even extinction. But there are not sufficient data to indicate whether or not this distinction matters for the production of regression. Recovery Following Massed or put Extinction TrialsThere is reason to anticipate that conducting extinction with short intertrial intervals may encourage more rapid response decrement followed by more substantial recovery. Certainly this is the expectation of accounts such as that of Hull, which emphasizes short-term fatigue-like effects, and of Estes, which emphasizes that massing of trials would yield repeated sampling of the same stimulus elements but neglect of others. Indeed, one might argue that there is a logical sense in which spaced trials should lead to slower decrementand less recovery.Presumably widely spaced trials would allow for any recovery between individual trials, resulting in slower behavioral loss over the course of an extinction procedure but more substantial change by the time that a test for recovery is imposed. Despite the appeal of these arguments, the evidence on the impact of massing or spacing extinction trials is quite mixed. A number of investigators (see Rescorla and Durlach 1987 Cain et al. 2003) have reported that massing produces rapid loss of performance. However, Rescorla and Durlach reported no difference in the magnitude of responding in a subsequent test for spontaneous recovery and Cain et al. (2003) reported continued less responding after massed extinction even with the passage of time. To complicate matters further, Stanley (1952) reported that for an subservient training task, massing slowed extinction on one measure and speeded it on another in an instrumental prime(prenominal) situation.Interval Between Learning and ExtinctionAlthough most attention has focused on the interval between extinction and the recovery test, it is also of interest to ask about the impact of the interval between the original training and extinct ion, as a determinant of spontaneous recovery. The retrieval theory proposed by Spear and the weighting rule described by Devenport both suggest that spontaneous recovery should be maximal when the interval between acquisition and extinction is minimized. In both cases, the intuition is that when training and extinction are close in time, it should be more difficult for the animal to recall which is the more recent. Immediately after extinction, the relative temporal recency of the nonreinforced experience should be maximal. However, as time passes, and the two experiences are more equally long-distance in time, they should become more equivalent in their likelihood of being retrieved.The increase in the relative likelihood of retrieving the original acquisition experience would then produce spontaneous recovery. A similar think would lead to the relatively greater impact of the acquisition experience according to the weighting rule. Mechanisms of recovery that appeal to the loss of the extinction experience have no natural way to predict that the interval between training and extinction should matter. Unfortunately, there are very few attempts to examine this possibility. There is some adjuvant evidence from studies of proactive inhibition in humans (Underwood and Freund 1968) and fromcounter-conditioning in rats (Gordon and Spear 1973), but little for the case of extinction.Recently, Rescorla (2004) has reported that a longer time interval between training and test diminishes spontaneous recovery in magazine approach and instrumental responding in rats and in sign-tracking in pigeons. One illustration is shown in Figure 4. That figure displays the results of extinction and testing with two stimuli given acquisition, extinction, and a test for spontaneous recovery in a magazine-approach procedure using rat subjects. The stimuli shared the same 48-h recovery interval after extinction but differed in that a greater interval (8 d versus 1 d) intervened betwee n training and extinction for S1 than for S2. The two stimuli showed virtually identical behavior over the course of extinction. However, the results of a test for spontaneous recovery given 48 h after extinction show greater spontaneous recovery for the stimulus with the shorter training/extinction interval (S2).Figure 4View larger versionIn this pageIn a new windowDownload as PowerPoint SlideFigure 4Evidence for greater spontaneous recovery with a greater interval between training and extinction. Rat subjects were given Pavlovian magazine-approach training, extinction, and a common test for spontaneous recovery with two stimuli, S1 and S2. The stimuli differed in the interval between their original training and extinction. Results such as these suggest that, consistent with some retrieval theories, spontaneous recovery may be a decreasing function of the acquisition/extinction interval. But clearly more work needs to be done on this potentially informative parameter. Previous Sect ionNext SectionConclusionThe picture that emerges from this discussion of spontaneous recovery is one of a process that is greatly in need of further empirical investigation. The available evidence fails to identify any one proposed process as the sole basis for spontaneous recovery. However, there is also evidence in support of all of the suggestions so far offered. This, togetherwith the ubiquity of spontaneous recovery, encourages the belief that it is a result that is multiply determined. Perhaps this is not surprising because it seems almost certain that the response decrement that is observed in extinction itself has multiple contributors.The fact that spontaneous recovery is likely to have multiple sources limits our ability to use it to identify the learning underlying extinction. The demonstration that extinction does not fully remove all of original acquisition seems secure. Spontaneous recovery is joined by a variety of other phenomena, such as disinhibition, renewal, re instatement, and augmented summation (see Reberg 1972) as a basis for that inference. But the simple observation of spontaneous recovery does not force the inference that all of original learning remains nor even that the learning that occurred during extinction fades in time.In the light of this conclusion, it is unfortunate that we do not have a clearer picture of how some of the parameters of most potential interest affect spontaneous recovery. But it suggests that if one is to use spontaneous recovery as a motherfucker to understand the nature of the processes occurring in extinction, one cannot simply celebrate its occurrence or its failure to occur. We will have to do much more analytic experiments determining the circumstances under which it occurs in the particular extinction situation under study.