- Email: [email protected]
Contextual influences on liking and preference
ARTICLE IN PRESS
Appetite 49 (2007) 679–682 www.elsevier.com/locate/appet
Short communication
Contextual influences on liking and preference Debra A. Zellner Montclair State University, Montclair, NJ 07043, USA Received 12 February 2007; accepted 29 April 2007
Abstract The paper addresses the topic of how much an individual likes a stimulus and also how much that individual prefers it to other stimuli. Research is reviewed showing that the context in which the stimulus is presented affects both liking and preference judgments. Having subjects think of the context stimuli and the test stimuli as being in different categories reduces the impact of the context stimuli on the ratings of the test stimuli and might be used to avoid such context effects in determining liking of and preferences for stimuli. r 2007 Elsevier Ltd. All rights reserved. Keywords: Hedonics; Context effects; Preference; Liking
Introduction If people ask us how much we like a particular food with which we are familiar, we have no difficulty telling them. While there are certainly ways to influence how much someone likes a particular food such as conditioned taste aversions and flavor–flavor conditioning (see Zellner, 1991), we believe those judgments to be fairly stable. We believe that how much we like a food today should be similar, if not identical, to how much we like it tomorrow. We certainly do not expect that what we think is good today will be bad tomorrow (or vice versa). However, our ratings of the ‘‘goodness’’ of stimuli vary considerably. In fact, what is rated as ‘‘good’’ in one context can be rated as ‘‘bad’’ in another. Although we perceive ourselves as giving absolute judgments of the hedonic quality of an object such as a food, we are in fact greatly influenced by the goodness of stimuli we experience before those we are rating. It appears that a stimulus’ goodness is dependent upon the context in which it is presented. This fact can influence how much we enjoy things in everyday life (see Parducci, 1995 for a discussion of context effects on happiness). It is also of practical concern when companies are trying to find out how much, or even whether, consumers will like their new product. E-mail address: [email protected] 0195-6663/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.appet.2007.04.008
The answer may depend upon the context in which the product is presented. The fact that context alters hedonic (i.e., goodness) judgments was pointed out as long ago as 1898 (Fechner, 1898). In his book Vorschule der Aesthetik, II, Gustav Fechner describes hedonic contrast as follows: ‘‘That which gives pleasure gives more pleasure the more it enters into contrast with sources of displeasure or of lesser pleasure; and a corresponding proposition holds for that which gives displeasure.’’ (as translated by Beebe-Center, 1965, pg. 222). So Fechner believed that good things can make other things worse and bad things can make them better. Fechner also pointed out that in order for context stimuli to influence what we will call the ‘‘test’’ stimuli, ‘‘the two factors had to bear a certain resemblance to each other’’ (Beebe-Center, 1965, pg. 223). So, in other words, the context and test stimuli had to be from the same category of stimuli Categorization I and my collaborators have been investigating hedonic contrast in order to determine if what Fechner said is true. What Fechner said about the effect of categorization on contrast made us wonder if some people’s ratings of apples are influenced by oranges because they think of them as being ‘‘fruit’’ whereas for other people oranges do not influence the ratings of apples because they are viewed as
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different things. If there were both kinds of people then we should find that those who put the ‘‘good’’ and ‘‘less good’’ stimuli in a single category will like the ‘‘less good’’ version less than will those who put the ‘‘good’’ and ‘‘less good’’ stimuli in different categories. Hedonic contrast should only occur among people who put all versions in the same category. We tested this using coffee which has ‘‘good’’ and ‘‘less good’’ versions. In our first study (Zellner, Kern, & Parker, 2002), we looked at people’s liking for ordinary canned coffee (the ‘‘less good’’ version of coffee). In order to be in the study subjects also had to consume the ‘‘good’’ version, gourmet coffee as bought in two coffee shops where we collected data. We asked subjects to give hedonic ratings for the ordinary canned coffee and the gourmet coffee they most commonly consumed. As we expected, people consistently judged the gourmet coffee as very hedonically positive and the ordinary coffee as considerably less good. We also asked them to tell us whether they thought of the two versions as being the same or different beverages. The people who said ‘‘same’’ think of them as being in the same category (i.e., coffee) and those who said ‘‘different’’ think of them as being in two different categories (presumably ordinary and gourmet coffee). If Fechner was right, then only people who thought of the two kinds of coffees as the same beverage would show hedonic contrast. That would result in the ‘‘same’’ group rating the less good ordinary canned coffee as less hedonically positive than the ‘‘different’’ group. That is indeed what we found. Those subjects who thought of both types of coffee as the same beverage rated the ordinary canned coffee as being hedonically negative (i.e., they disliked it). On the other hand, the subjects who thought of the two types of coffees as different beverages liked the ordinary coffee, although less than the gourmet coffee. Some of these subjects reported that they still drank ordinary canned coffee at home while those who thought of the two coffees as the same beverage had a hard time drinking ordinary canned coffee anymore. Drinking gourmet coffee made ordinary coffee unacceptable only for the subjects who thought the two coffees were members of the same category. We (Zellner et al., 2002) replicated this finding that failure to sub-categorize can make less good versions of an item bad if a better version is introduced. This time we surveyed beer drinkers who had consumed both ‘‘regular’’ beer (e.g., Budweiser) and ‘‘specialty’’ beer (e.g., imports or microbrews). We again saw the same effect. The less good ‘‘regular’’ beer suffered in comparison with the better imports and microbrews only among people who thought of the two kinds of beers as being the same beverage. Those individuals now disliked the ‘‘regular’’ beer, whereas those who put the two kinds of beers in different categories still liked the ‘‘regular’’ beer, although less than the ‘‘specialty’’ beer. These studies confirmed what Fechner had pointed out: lumping good and less good versions of similar items into the same category results in disliking the less good versions,
but separating them into two categories allows us to like both versions to some degree. The next question we investigated was whether instructing subjects to put good and less good versions of stimuli into one category or two can produce or prevent hedonic contrast. Our next studies (Zellner, Rohm, Bassetti, & Parker, 2003) involved experimentally manipulating categorization of context and test stimuli to determine (1) if hedonic contrast would occur when subjects were told that the ‘‘good’’ context stimuli were in the same category as the ‘‘less good’’ test stimuli, and (2) if formation of that hedonic contrast would be prevented by informing subjects that the two sets of stimuli were members of different categories. In the first experiment, four groups of subjects were asked to rate how much they liked the taste of two test beverages (Mistic brand juice blends diluted with enough water to make them close to hedonically neutral). Two no-context control groups rated only those two test beverages. One control group was told that they were rating two fruit juices. The other control group was told that they were rating two commercial drinks. The two context groups drank and rated the hedonic value of eight context full-strength Mistic beverages prior to rating the two test beverages. One context group was told that they were rating fruit juices and the other was told that they were rating a set of eight fruit juices followed by two commercial drinks. Subjects in both control groups who only rated the two diluted test beverages rated them as slightly hedonically positive. However, subjects reported disliking the dilute juices if they were told that both the good full-strength and less good dilute test juices were ‘‘juices.’’ This effect was attenuated if they were told that the full-strength context juices were ‘‘juices’’ and the dilute test juices were ‘‘commercial drinks.’’ We found similar results using pictures of birds as stimuli. When hedonically positive tropical birds preceded less attractive North American birds subjects reported that they found the North American birds unattractive. However, subjects told to categorize the two sets of birds into ‘‘Tropical birds’’ and ‘‘North American birds’’ found the North American test birds somewhat attractive. Thus, hedonic contrast is reduced when subjects are told to put the context stimuli in one category and the test stimuli in another. However, in these studies, the hedonic contrast was not eliminated by telling people to categorize. For example, in the fruit juice study both groups rating the context juices before the test juices showed hedonic contrast. However, the degree of contrast in the group told to categorize was significantly less than those who were not told to categorize. Why did being told to categorize not completely eliminate the hedonic contrast? People may have a tendency to categorize objects in certain ways so that telling them to think about things in another way is not completely successful. For example, the people in our bird study probably naturally made one category of ‘‘birds’’ and the information about Tropical and North American birds did not totally override their tendency to see all birds as birds. However, if they had been
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ornithologists or birders we might have seen different results. Experts tend to make finer categories of the stimuli with which they are expert than do novices. Bird experts would view the stimuli as coming from entirely separate categories and therefore hedonic contrast would not occur. To test this we conducted a study in which flower experts and novices rated the attractiveness of flowers (Rota & Zellner, 2007). We took advantage of the fact that a flower expert should categorize orchids differently from iris whereas a novice will see them all as ‘‘flowers.’’ Groups of experts and novices rated the attractiveness of ‘‘less attractive’’ test orchids preceded by either attractive orchids, attractive iris, or nothing. As in the preceding studies, rating the attractive orchids or the attractive iris prior to the less attractive test orchids reduced the attractiveness rating of these orchids in the novice groups (since they saw them as all flowers). However, the experts only showed hedonic contrast when attractive orchids preceded the test orchids, not when attractive iris did. In this case, the experts saw iris and orchids as being in entirely different categories and thus viewing the iris did not influence the ratings of the subsequently presented test orchids at all. In fact, among the experts the test orchids viewed after the attractive iris were rated exactly the same as when they were viewed without context stimuli. So, as Fechner said, hedonic contrast only occurs when the context and test stimuli ‘‘bear a certain resemblance to each other.’’ If people think of the two sets of stimuli as unrelated (e.g., ‘‘apples and oranges’’ rather than ‘‘fruit’’) no contrast occurs because the stimuli are not compared. However, if subjects view apples and oranges as ‘‘fruit’’ they will be compared and hedonic contrast will occur to the extent to which they are related. Positive and negative contrast Fechner also said that hedonic contrast occurs in two directions. Negative contrast occurs when good things make less good things worse and positive contrast occurs when bad things make less bad things better. So far, all of the studies I have described are demonstrations of negative hedonic contrast. If Fechner is right, it should also be possible to produce positive hedonic contrast. In a study (Dolese, Zellner, Vasserman, & Parker, 2005) using pictures of paintings by the Spanish artist Francisco Goya as stimuli, we demonstrated that positive hedonic contrast can occur. Three groups of subjects were asked to rate the attractiveness of two of Goya’s ‘‘tapestry’’ painting which depict people in pastoral settings. One group simply rated those two paintings. The two additional groups rated those two paintings after viewing and rating five of Goya’s paintings from his Dark Period. (These are very darkly colored and often depict gory, disturbing scenes; one was Saturn Devouring His Son which depicts the god Saturn munching on what looks to be a human body.) One of the groups viewing the dark period paintings was told that they were expressionist paintings and the other group was told
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that they were paintings by Goya. All groups were told that the tapestry paintings were painted by Goya. Subjects who saw both the Dark Period and ‘‘tapestry paintings’’ and were told that all of the paintings were by Goya rated the two tapestry paintings as more attractive than did those subjects who rated only the tapestry paintings. There was less positive hedonic contrast for subjects who categorized the two sets of paintings into dark Expressionist paintings and tapestry paintings by Goya. So, once again, Fechner was correct, hedonic contrast works in both directions. Comparing mediocre stimuli to good ones makes them pale in comparison (negative hedonic contrast). Comparing mediocre stimuli to bad ones makes them appear better (positive hedonic contrast). In addition, hedonic contrast occurring in both directions is affected by categorization. Beyond Fechner What Fechner pointed out over 100 years ago concerning hedonic judgments appears to be true. In fact, the effects he describes with hedonic judgments also appear to occur with intensity judgments (see for example, Pol, Hijman, Barre, & van Ree, 1998). If a strong stimulus precedes a weaker one, that weaker one appears to be less intense than it would have if the strong stimuli had not preceded it. If the stimuli are sounds and the strong and weak sounds are of different frequencies, the intensity contrast does not occur (e.g., Arieh & Marks, 2003). It appears that sounds of different frequencies are treated as if they were in different categories and as with hedonic judgments, contrast does not occur. Another thing that occurs with sound intensity contrast is the reduction of discriminability of two weaker tones when they follow loud ones. Not only do loud sounds make less loud sounds softer but they also make them less discriminable. Parker, Murphy, and Schneider (2002) showed that two discriminable tones of medium loudness (in the 20–50 dB range) were less discriminable following a loud sound. Does this phenomenon seen under conditions that produce intensity contrast also occur under conditions producing hedonic contrast? Will subjects display less of a preference for one mediocre stimulus over another when those stimuli are preceded by much better stimuli? We (Zellner, Allen, Henley, & Parker, 2006) investigated this question by first replicating the hedonic contrast study described previously using full-strength (good) and diluted (less good) fruit juices. When four full-strength good juices preceded the less good diluted test juices, hedonic contrast occurred. The two dilute test juices were judged as less good after the good concentrated juices than when judged alone. Using those same juices presented in the same order, we then did a second study to see if the degree of preference for one of the dilute test juices over the other was also reduced when those juices were preceded by the good fullstrength juices. In this second study, the juices were presented in pairs. One group received only the diluted
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pair while the other group received two pairs of fullstrength juices followed by the pair of diluted juices. For each pair of juices, subjects were asked if they liked one member of the pair more than the other and if so to rate by how much they preferred their favorite. Subjects who had tasted all three pairs indicated a much weaker preference for one dilute test juice over another than did subjects who had tasted and rated only the dilute test juices. So, not only can good stimuli make less good stimuli even less good, they can also make them less hedonically different, paralleling the effect seen in sound intensity. I suspect that this phenomenon, like the categorization effect in hedonic contrast, occurs in real life. I also believe that this phenomenon accompanies hedonic contrast. Experiencing a good gourmet coffee might reduce one’s preference for one canned coffee over another. Application These findings pose a great challenge to both researchers and companies introducing new products to the marketplace. They suggest than anybody trying to determine how much some stimulus (or product) will be liked and if it will be preferred to another stimulus should be concerned about the context in which the stimulus is presented to the subject. People might like a stimulus (or product) in one context and dislike it in another. They might slightly prefer the stimulus (or product) in one context and not prefer it in another. Unless we can figure out how to control the context in which something is presented we will have no idea of the acceptability of the stimulus or if people will prefer it to another with which they are already familiar. In the case of a new product, producers will not know if consumers will like their product or prefer it to one already on the market. Because hedonic judgments seem to be relative, one solution for researchers and companies is to have people consider the stimulus or product to be unique. This will prevent its comparison to other (possibly better) stimulus or products. Conclusion As Fechner suggested long ago, how good something is (and, it turns out, how much we prefer one thing over another) depends upon both the context in which we experience the stimulus and how we think about it. This fact explains a lot about why some people like a particular item and others do not. It can also help explain why some people have very strong preferences among a group of similar items and others do not. Perceiving an item as ‘‘good’’ will depend upon what other items an individual has been exposed to in the past (probably mainly the recent past). This is particularly true if the individual has been exposed to items that are substantially better or worse than the test item. In addition, this exposure will influence hedonic judgments for some people more than others
depending upon how they think about the original item and the more hedonically extreme item. Individuals who view the items as being in the same category will compare them and hedonic contrast will occur (the item will be judged as better or worse than it would otherwise in contrast to the more extreme item). On the other hand, individuals who see the two items as being from different categories will show little or no hedonic contrast (depending upon the degree to which they separate the items). This contributes to the great variability seen among individuals in the hedonic evaluation of any item and also to the changes that can occur within an individual. Acknowledgments This paper is based on a presentation to the Columbia University Seminar on Appetitive Behavior, February 8, 2007, Harry R. Kissileff, Chairman, supported in part by GlaxoSmithKline and The New York Obesity Research Center, St. Luke’s/Roosevelt Hospital. The research described in this paper was done in collaboration with Scott Parker (American University) and numerous graduate and undergraduate students from Montclair State University and Shippensburg University. I would like to thank Paul Rozin for inspiring this line of research. References Arieh, Y., & Marks, L. E. (2003). Recalibrating the auditory system: A speed–accuracy analysis of intensity perception. Journal of Experimental Psychology: Human Perception and Performance, 29, 523–536. Beebe-Center, J. G. (1965). The psychology of pleasantness and unpleasantness. New York: Russell & Russell (Original work published 1932). Dolese, M., Zellner, D., Vasserman, M., & Parker, S. (2005). Categorization affects hedonic contrast in the visual arts. Bulletin of Psychology and the Arts, 5, 21–25. Fechner, G. T. (1898). Vorschule der Aesthetik, II (2nd ed.). Leipzig: Breitkopf & Hartel. Parducci, A. (1995). Happiness, pleasure, and judgment: The Contextual Theory and its applications. Mahwah NJ: Lawrence Erlbaum Associates. Parker, S., Murphy, D., & Schneider, B. (2002). Top-down gain control in the auditory system: Evidence from identification and discrimination experiments. Perception and Psychophysics, 64, 598–615. Pol, H. E. H., Hijman, R., Barre, W. F. C., & van Ree, J. M. (1998). Effects of context on judgments of odor intensities in humans. Chemical Senses, 23, 131–135. Rota, L., & Zellner, D. A. (2007). The categorization effect in contrast: Experts differ from novices. Psychonomic Bulletin and Review, 14, 179–183. Zellner, D. A. (1991). How foods get to be liked: Some general mechanisms and some special cases. In R. Bolles (Ed.), The hedonics of taste (pp. 199–217). Hillsdale, New Jersey: Lawrence Erlbaum Associates. Zellner, D. A., Allen, D., Henley, M., & Parker, S. (2006). Hedonic contrast and condensation: Good stimuli make mediocre stimuli less good and less different. Psychonomic Bulletin and Review, 13, 235–239. Zellner, D. A., Kern, B. B., & Parker, S. (2002). Protection for the good: Subcategorization reduces hedonic contrast. Appetite, 38, 175–180. Zellner, D. A., Rohm, E. A., Bassetti, T. L., & Parker, S. (2003). Compared to what? Effects of categorization on hedonic contrast. Psychonomic Bulletin and Review, 10, 468–473.
Appetite 49 (2007) 679–682 www.elsevier.com/locate/appet
Short communication
Contextual influences on liking and preference Debra A. Zellner Montclair State University, Montclair, NJ 07043, USA Received 12 February 2007; accepted 29 April 2007
Abstract The paper addresses the topic of how much an individual likes a stimulus and also how much that individual prefers it to other stimuli. Research is reviewed showing that the context in which the stimulus is presented affects both liking and preference judgments. Having subjects think of the context stimuli and the test stimuli as being in different categories reduces the impact of the context stimuli on the ratings of the test stimuli and might be used to avoid such context effects in determining liking of and preferences for stimuli. r 2007 Elsevier Ltd. All rights reserved. Keywords: Hedonics; Context effects; Preference; Liking
Introduction If people ask us how much we like a particular food with which we are familiar, we have no difficulty telling them. While there are certainly ways to influence how much someone likes a particular food such as conditioned taste aversions and flavor–flavor conditioning (see Zellner, 1991), we believe those judgments to be fairly stable. We believe that how much we like a food today should be similar, if not identical, to how much we like it tomorrow. We certainly do not expect that what we think is good today will be bad tomorrow (or vice versa). However, our ratings of the ‘‘goodness’’ of stimuli vary considerably. In fact, what is rated as ‘‘good’’ in one context can be rated as ‘‘bad’’ in another. Although we perceive ourselves as giving absolute judgments of the hedonic quality of an object such as a food, we are in fact greatly influenced by the goodness of stimuli we experience before those we are rating. It appears that a stimulus’ goodness is dependent upon the context in which it is presented. This fact can influence how much we enjoy things in everyday life (see Parducci, 1995 for a discussion of context effects on happiness). It is also of practical concern when companies are trying to find out how much, or even whether, consumers will like their new product. E-mail address: [email protected] 0195-6663/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.appet.2007.04.008
The answer may depend upon the context in which the product is presented. The fact that context alters hedonic (i.e., goodness) judgments was pointed out as long ago as 1898 (Fechner, 1898). In his book Vorschule der Aesthetik, II, Gustav Fechner describes hedonic contrast as follows: ‘‘That which gives pleasure gives more pleasure the more it enters into contrast with sources of displeasure or of lesser pleasure; and a corresponding proposition holds for that which gives displeasure.’’ (as translated by Beebe-Center, 1965, pg. 222). So Fechner believed that good things can make other things worse and bad things can make them better. Fechner also pointed out that in order for context stimuli to influence what we will call the ‘‘test’’ stimuli, ‘‘the two factors had to bear a certain resemblance to each other’’ (Beebe-Center, 1965, pg. 223). So, in other words, the context and test stimuli had to be from the same category of stimuli Categorization I and my collaborators have been investigating hedonic contrast in order to determine if what Fechner said is true. What Fechner said about the effect of categorization on contrast made us wonder if some people’s ratings of apples are influenced by oranges because they think of them as being ‘‘fruit’’ whereas for other people oranges do not influence the ratings of apples because they are viewed as
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different things. If there were both kinds of people then we should find that those who put the ‘‘good’’ and ‘‘less good’’ stimuli in a single category will like the ‘‘less good’’ version less than will those who put the ‘‘good’’ and ‘‘less good’’ stimuli in different categories. Hedonic contrast should only occur among people who put all versions in the same category. We tested this using coffee which has ‘‘good’’ and ‘‘less good’’ versions. In our first study (Zellner, Kern, & Parker, 2002), we looked at people’s liking for ordinary canned coffee (the ‘‘less good’’ version of coffee). In order to be in the study subjects also had to consume the ‘‘good’’ version, gourmet coffee as bought in two coffee shops where we collected data. We asked subjects to give hedonic ratings for the ordinary canned coffee and the gourmet coffee they most commonly consumed. As we expected, people consistently judged the gourmet coffee as very hedonically positive and the ordinary coffee as considerably less good. We also asked them to tell us whether they thought of the two versions as being the same or different beverages. The people who said ‘‘same’’ think of them as being in the same category (i.e., coffee) and those who said ‘‘different’’ think of them as being in two different categories (presumably ordinary and gourmet coffee). If Fechner was right, then only people who thought of the two kinds of coffees as the same beverage would show hedonic contrast. That would result in the ‘‘same’’ group rating the less good ordinary canned coffee as less hedonically positive than the ‘‘different’’ group. That is indeed what we found. Those subjects who thought of both types of coffee as the same beverage rated the ordinary canned coffee as being hedonically negative (i.e., they disliked it). On the other hand, the subjects who thought of the two types of coffees as different beverages liked the ordinary coffee, although less than the gourmet coffee. Some of these subjects reported that they still drank ordinary canned coffee at home while those who thought of the two coffees as the same beverage had a hard time drinking ordinary canned coffee anymore. Drinking gourmet coffee made ordinary coffee unacceptable only for the subjects who thought the two coffees were members of the same category. We (Zellner et al., 2002) replicated this finding that failure to sub-categorize can make less good versions of an item bad if a better version is introduced. This time we surveyed beer drinkers who had consumed both ‘‘regular’’ beer (e.g., Budweiser) and ‘‘specialty’’ beer (e.g., imports or microbrews). We again saw the same effect. The less good ‘‘regular’’ beer suffered in comparison with the better imports and microbrews only among people who thought of the two kinds of beers as being the same beverage. Those individuals now disliked the ‘‘regular’’ beer, whereas those who put the two kinds of beers in different categories still liked the ‘‘regular’’ beer, although less than the ‘‘specialty’’ beer. These studies confirmed what Fechner had pointed out: lumping good and less good versions of similar items into the same category results in disliking the less good versions,
but separating them into two categories allows us to like both versions to some degree. The next question we investigated was whether instructing subjects to put good and less good versions of stimuli into one category or two can produce or prevent hedonic contrast. Our next studies (Zellner, Rohm, Bassetti, & Parker, 2003) involved experimentally manipulating categorization of context and test stimuli to determine (1) if hedonic contrast would occur when subjects were told that the ‘‘good’’ context stimuli were in the same category as the ‘‘less good’’ test stimuli, and (2) if formation of that hedonic contrast would be prevented by informing subjects that the two sets of stimuli were members of different categories. In the first experiment, four groups of subjects were asked to rate how much they liked the taste of two test beverages (Mistic brand juice blends diluted with enough water to make them close to hedonically neutral). Two no-context control groups rated only those two test beverages. One control group was told that they were rating two fruit juices. The other control group was told that they were rating two commercial drinks. The two context groups drank and rated the hedonic value of eight context full-strength Mistic beverages prior to rating the two test beverages. One context group was told that they were rating fruit juices and the other was told that they were rating a set of eight fruit juices followed by two commercial drinks. Subjects in both control groups who only rated the two diluted test beverages rated them as slightly hedonically positive. However, subjects reported disliking the dilute juices if they were told that both the good full-strength and less good dilute test juices were ‘‘juices.’’ This effect was attenuated if they were told that the full-strength context juices were ‘‘juices’’ and the dilute test juices were ‘‘commercial drinks.’’ We found similar results using pictures of birds as stimuli. When hedonically positive tropical birds preceded less attractive North American birds subjects reported that they found the North American birds unattractive. However, subjects told to categorize the two sets of birds into ‘‘Tropical birds’’ and ‘‘North American birds’’ found the North American test birds somewhat attractive. Thus, hedonic contrast is reduced when subjects are told to put the context stimuli in one category and the test stimuli in another. However, in these studies, the hedonic contrast was not eliminated by telling people to categorize. For example, in the fruit juice study both groups rating the context juices before the test juices showed hedonic contrast. However, the degree of contrast in the group told to categorize was significantly less than those who were not told to categorize. Why did being told to categorize not completely eliminate the hedonic contrast? People may have a tendency to categorize objects in certain ways so that telling them to think about things in another way is not completely successful. For example, the people in our bird study probably naturally made one category of ‘‘birds’’ and the information about Tropical and North American birds did not totally override their tendency to see all birds as birds. However, if they had been
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ornithologists or birders we might have seen different results. Experts tend to make finer categories of the stimuli with which they are expert than do novices. Bird experts would view the stimuli as coming from entirely separate categories and therefore hedonic contrast would not occur. To test this we conducted a study in which flower experts and novices rated the attractiveness of flowers (Rota & Zellner, 2007). We took advantage of the fact that a flower expert should categorize orchids differently from iris whereas a novice will see them all as ‘‘flowers.’’ Groups of experts and novices rated the attractiveness of ‘‘less attractive’’ test orchids preceded by either attractive orchids, attractive iris, or nothing. As in the preceding studies, rating the attractive orchids or the attractive iris prior to the less attractive test orchids reduced the attractiveness rating of these orchids in the novice groups (since they saw them as all flowers). However, the experts only showed hedonic contrast when attractive orchids preceded the test orchids, not when attractive iris did. In this case, the experts saw iris and orchids as being in entirely different categories and thus viewing the iris did not influence the ratings of the subsequently presented test orchids at all. In fact, among the experts the test orchids viewed after the attractive iris were rated exactly the same as when they were viewed without context stimuli. So, as Fechner said, hedonic contrast only occurs when the context and test stimuli ‘‘bear a certain resemblance to each other.’’ If people think of the two sets of stimuli as unrelated (e.g., ‘‘apples and oranges’’ rather than ‘‘fruit’’) no contrast occurs because the stimuli are not compared. However, if subjects view apples and oranges as ‘‘fruit’’ they will be compared and hedonic contrast will occur to the extent to which they are related. Positive and negative contrast Fechner also said that hedonic contrast occurs in two directions. Negative contrast occurs when good things make less good things worse and positive contrast occurs when bad things make less bad things better. So far, all of the studies I have described are demonstrations of negative hedonic contrast. If Fechner is right, it should also be possible to produce positive hedonic contrast. In a study (Dolese, Zellner, Vasserman, & Parker, 2005) using pictures of paintings by the Spanish artist Francisco Goya as stimuli, we demonstrated that positive hedonic contrast can occur. Three groups of subjects were asked to rate the attractiveness of two of Goya’s ‘‘tapestry’’ painting which depict people in pastoral settings. One group simply rated those two paintings. The two additional groups rated those two paintings after viewing and rating five of Goya’s paintings from his Dark Period. (These are very darkly colored and often depict gory, disturbing scenes; one was Saturn Devouring His Son which depicts the god Saturn munching on what looks to be a human body.) One of the groups viewing the dark period paintings was told that they were expressionist paintings and the other group was told
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that they were paintings by Goya. All groups were told that the tapestry paintings were painted by Goya. Subjects who saw both the Dark Period and ‘‘tapestry paintings’’ and were told that all of the paintings were by Goya rated the two tapestry paintings as more attractive than did those subjects who rated only the tapestry paintings. There was less positive hedonic contrast for subjects who categorized the two sets of paintings into dark Expressionist paintings and tapestry paintings by Goya. So, once again, Fechner was correct, hedonic contrast works in both directions. Comparing mediocre stimuli to good ones makes them pale in comparison (negative hedonic contrast). Comparing mediocre stimuli to bad ones makes them appear better (positive hedonic contrast). In addition, hedonic contrast occurring in both directions is affected by categorization. Beyond Fechner What Fechner pointed out over 100 years ago concerning hedonic judgments appears to be true. In fact, the effects he describes with hedonic judgments also appear to occur with intensity judgments (see for example, Pol, Hijman, Barre, & van Ree, 1998). If a strong stimulus precedes a weaker one, that weaker one appears to be less intense than it would have if the strong stimuli had not preceded it. If the stimuli are sounds and the strong and weak sounds are of different frequencies, the intensity contrast does not occur (e.g., Arieh & Marks, 2003). It appears that sounds of different frequencies are treated as if they were in different categories and as with hedonic judgments, contrast does not occur. Another thing that occurs with sound intensity contrast is the reduction of discriminability of two weaker tones when they follow loud ones. Not only do loud sounds make less loud sounds softer but they also make them less discriminable. Parker, Murphy, and Schneider (2002) showed that two discriminable tones of medium loudness (in the 20–50 dB range) were less discriminable following a loud sound. Does this phenomenon seen under conditions that produce intensity contrast also occur under conditions producing hedonic contrast? Will subjects display less of a preference for one mediocre stimulus over another when those stimuli are preceded by much better stimuli? We (Zellner, Allen, Henley, & Parker, 2006) investigated this question by first replicating the hedonic contrast study described previously using full-strength (good) and diluted (less good) fruit juices. When four full-strength good juices preceded the less good diluted test juices, hedonic contrast occurred. The two dilute test juices were judged as less good after the good concentrated juices than when judged alone. Using those same juices presented in the same order, we then did a second study to see if the degree of preference for one of the dilute test juices over the other was also reduced when those juices were preceded by the good fullstrength juices. In this second study, the juices were presented in pairs. One group received only the diluted
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pair while the other group received two pairs of fullstrength juices followed by the pair of diluted juices. For each pair of juices, subjects were asked if they liked one member of the pair more than the other and if so to rate by how much they preferred their favorite. Subjects who had tasted all three pairs indicated a much weaker preference for one dilute test juice over another than did subjects who had tasted and rated only the dilute test juices. So, not only can good stimuli make less good stimuli even less good, they can also make them less hedonically different, paralleling the effect seen in sound intensity. I suspect that this phenomenon, like the categorization effect in hedonic contrast, occurs in real life. I also believe that this phenomenon accompanies hedonic contrast. Experiencing a good gourmet coffee might reduce one’s preference for one canned coffee over another. Application These findings pose a great challenge to both researchers and companies introducing new products to the marketplace. They suggest than anybody trying to determine how much some stimulus (or product) will be liked and if it will be preferred to another stimulus should be concerned about the context in which the stimulus is presented to the subject. People might like a stimulus (or product) in one context and dislike it in another. They might slightly prefer the stimulus (or product) in one context and not prefer it in another. Unless we can figure out how to control the context in which something is presented we will have no idea of the acceptability of the stimulus or if people will prefer it to another with which they are already familiar. In the case of a new product, producers will not know if consumers will like their product or prefer it to one already on the market. Because hedonic judgments seem to be relative, one solution for researchers and companies is to have people consider the stimulus or product to be unique. This will prevent its comparison to other (possibly better) stimulus or products. Conclusion As Fechner suggested long ago, how good something is (and, it turns out, how much we prefer one thing over another) depends upon both the context in which we experience the stimulus and how we think about it. This fact explains a lot about why some people like a particular item and others do not. It can also help explain why some people have very strong preferences among a group of similar items and others do not. Perceiving an item as ‘‘good’’ will depend upon what other items an individual has been exposed to in the past (probably mainly the recent past). This is particularly true if the individual has been exposed to items that are substantially better or worse than the test item. In addition, this exposure will influence hedonic judgments for some people more than others
depending upon how they think about the original item and the more hedonically extreme item. Individuals who view the items as being in the same category will compare them and hedonic contrast will occur (the item will be judged as better or worse than it would otherwise in contrast to the more extreme item). On the other hand, individuals who see the two items as being from different categories will show little or no hedonic contrast (depending upon the degree to which they separate the items). This contributes to the great variability seen among individuals in the hedonic evaluation of any item and also to the changes that can occur within an individual. Acknowledgments This paper is based on a presentation to the Columbia University Seminar on Appetitive Behavior, February 8, 2007, Harry R. Kissileff, Chairman, supported in part by GlaxoSmithKline and The New York Obesity Research Center, St. Luke’s/Roosevelt Hospital. The research described in this paper was done in collaboration with Scott Parker (American University) and numerous graduate and undergraduate students from Montclair State University and Shippensburg University. I would like to thank Paul Rozin for inspiring this line of research. References Arieh, Y., & Marks, L. E. (2003). Recalibrating the auditory system: A speed–accuracy analysis of intensity perception. Journal of Experimental Psychology: Human Perception and Performance, 29, 523–536. Beebe-Center, J. G. (1965). The psychology of pleasantness and unpleasantness. New York: Russell & Russell (Original work published 1932). Dolese, M., Zellner, D., Vasserman, M., & Parker, S. (2005). Categorization affects hedonic contrast in the visual arts. Bulletin of Psychology and the Arts, 5, 21–25. Fechner, G. T. (1898). Vorschule der Aesthetik, II (2nd ed.). Leipzig: Breitkopf & Hartel. Parducci, A. (1995). Happiness, pleasure, and judgment: The Contextual Theory and its applications. Mahwah NJ: Lawrence Erlbaum Associates. Parker, S., Murphy, D., & Schneider, B. (2002). Top-down gain control in the auditory system: Evidence from identification and discrimination experiments. Perception and Psychophysics, 64, 598–615. Pol, H. E. H., Hijman, R., Barre, W. F. C., & van Ree, J. M. (1998). Effects of context on judgments of odor intensities in humans. Chemical Senses, 23, 131–135. Rota, L., & Zellner, D. A. (2007). The categorization effect in contrast: Experts differ from novices. Psychonomic Bulletin and Review, 14, 179–183. Zellner, D. A. (1991). How foods get to be liked: Some general mechanisms and some special cases. In R. Bolles (Ed.), The hedonics of taste (pp. 199–217). Hillsdale, New Jersey: Lawrence Erlbaum Associates. Zellner, D. A., Allen, D., Henley, M., & Parker, S. (2006). Hedonic contrast and condensation: Good stimuli make mediocre stimuli less good and less different. Psychonomic Bulletin and Review, 13, 235–239. Zellner, D. A., Kern, B. B., & Parker, S. (2002). Protection for the good: Subcategorization reduces hedonic contrast. Appetite, 38, 175–180. Zellner, D. A., Rohm, E. A., Bassetti, T. L., & Parker, S. (2003). Compared to what? Effects of categorization on hedonic contrast. Psychonomic Bulletin and Review, 10, 468–473.