How much do you like something? If people ask us how much we like a particular song, food, painting, or individual with which we are familiar, we have no difficulty telling them. Barring extreme events like getting sick after eating a food or getting dumped by a significant other, we believe those judgments to be stable. We believe that how much we like something today should be similar, if not identical, to how much we like it tomorrow. We certainly don't 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, 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 if, consumers will like their new product. 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. In his book Vorschule der Aesthetik, II,
Gustav Fechner described 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). Thus, 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). In other words, the context and test stimuli had to be from the same category of stimuli. Apples cannot influence our liking of oranges and vice versa.Categorization
My collaborators and I have been investigating hedonic contrast in order to determine if what Fechner said is true. First, we investigated whether categorization influences hedonic contrast. This line of research was begun because Paul Rozin, famous for his studies on food, told me I would enjoy more foods if I divided them into more categories. The issue at the time was my failure to like the food at a particular fast-food Indian restaurant in West Philadelphia. He said the problem was that I was comparing the Indian fast-food restaurant with a rather upscale Indian place I liked. If I divided Indian food into more categories (e.g., fast-food versus upscale), I would be able to enjoy both kinds of food because I would not be comparing the fast-food to the upscale food, and it would not suffer by contrast.
What he said to me made me 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 different things. If there were these two kinds of people, then we should find that those who think of the "good" and "less good" stimuli as being in a single category like the "less good" version less than do those who think of the "good" and "less good" stimuli as being from different categories. Hedonic contrast should only occur among people who put all versions in the same category.
What we needed was a category of stimuli that had "good" and "less good" versions which many people had sampled. 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, participants also had to consume the "good" version, gourmet coffee as bought in two coffee shops where we collected data. We asked participants 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 and those who said "different" think of them as being in two different categories. 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.
In fact, that is what we found. Those participants 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 participants who thought of the two types of coffees as different beverages liked the ordinary coffee, although less than the gourmet coffee. Some of these participants 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. Having drunk the gourmet coffee made the ordinary coffee unacceptable only for the participants who thought the two coffees were members of the same category.
We (Zellner, et al., 2002) replicated this finding that failure to 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 and Rozin 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. We found there were people like Rozin and other people like me. The next question to ask was whether we can make someone be like him or be like me through instruction. By telling people to put good and less good versions of stimuli into one category or two, can we produce or prevent hedonic contrast?
Our next studies (Zellner, Rohm, Bassetti, & Parker, 2003) involved experimentally manipulating categorization of context and test stimuli to determine: (a) if hedonic contrast would occur when participants were told that the "good" context stimuli were in the same category as the "less good" test stimuli, and (b) if formation of that hedonic contrast would be prevented by informing participants that the two sets of stimuli were members of different categories.
In the first experiment, three groups were asked to rate the attractiveness of 10 North American birds. The birds in this "test set" of pictures were average-looking birds with black/brown/white plumage (typical of this set would be a sparrow). One group, the control, judged the attractiveness of a context set of 10 birds which were similar in attractiveness to the test set, prior to rating the test set. The two experimental groups judged the attractiveness of a context set of 10 tropical birds with brightly colored plumage prior to rating the average-looking test set. One of these experimental groups was told that they were rating "birds," and the other group was told that they were rating a set of "Tropical birds" followed by "North American birds."
The participants in the group that was instructed to think of the birds as all being members of the same category, "birds," rated the test set of North American birds as being less attractive than did both the control group and the group that was told to categorize the birds into "Tropical" and "North American." In fact, as we found in the studies on coffee and beer, people in the group that was instructed that all stimuli were "birds" and therefore in the same category, rated the test birds as unattractive
when preceded by the tropical birds; whereas people in the group that was told to categorize the birds into two categories still found the North American test birds somewhat attractive.
We found similar results using fruit juices as stimuli. When hedonically positive full-strength juices preceded less good diluted ones, subjects reported disliking
the diluted juices if they were told that both the good full-strength and less good diluted test juices were "juices." However, this effect was attenuated if they were told that the full-strength versions were "juices," and the diluted test juices were "commercial drinks."
Thus, hedonic contrast is reduced when people 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 didn't being told to categorize completely eliminate the hedonic contrast? This manipulation is like Paul Rozin telling me to categorize fast-food and upscale Indian restaurants. I still know that both serve Indian food and that is my preferred level of categorizing. 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 ornithologists or birders, we might have seen different results. Experts tend to make finer categories of those stimuli about which they are experts 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, 2005). 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 showed hedonic contrast only 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 people 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. In this study, participants were asked to rate the attractiveness of two of Goya's "tapestry" paintings that depict people in pastoral settings. We used The Parasol
and The Swing.
One group simply rated those two paintings while two additional groups rated the two paintings after viewing and rating five of Goya's paintings from his Dark Period. These paintings are painted in very dark colors and often depict gory, disturbing scenes. One such painting which we used 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 that they were paintings by Goya. All groups were told that the test paintings were painted by Goya. Those subjects who were told that all of the paintings were by Francisco Goya rated the two test paintings as more attractive than did those who rated only the test paintings. That positive hedonic contrast was attenuated by telling the subjects to categorize the two sets of paintings into Expressionist paintings and those by Goya.
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 described with hedonic judgments also appear to occur with intensity judgments (see for example, Conner, Land & Booth, 1987, and Pol, Hijman, Baare, & 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, which Fechner did not discuss as occurring with hedonic 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 people 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, in press) 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 diluted 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 diluted test juices over the other was also reduced when those juices were preceded by the good full-strength juices. In this second study, the juices were presented in pairs. One group received only the diluted pair while the other group received two pairs of full-strength juices followed by the pair of diluted juices. For each pair of juices, participants were asked if they liked one member of the pair more than the other and if so to rate how much more they liked their favorite. Participants who had tasted all three pairs indicated a much weaker preference for one diluted test juice over another than did participants who had tasted and rated only the diluted 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.
Does this phenomenon, like the categorization effect in hedonic contrast, occur in real life? I suspect it does. Not only did I not like the fast-food Indian restaurant Paul Rozin had mentioned, but I really didn't care for any of the other ones in a small strip of Indian fast-food restaurants nearby. As far as I was concerned, none of them were good, and hedonically I rated the food about the same. Paul, on the other hand, had his favorites among them and his preferences were quite strong.
I also believe that this phenomenon accompanies hedonic contrast. Before I drank good coffee (in the times before gourmet coffee shops), I had preferences among brands of canned coffee. However, once I started to drink good coffee and grind my own beans, not only did I dislike canned coffee (being one of those folks who don't categorize), but I also stopped having any preference for one brand of canned coffee over another.
Obviously, my personal experience is not enough to determine if this phenomenon works to influence our preferences on a daily basis but the experimental evidence suggests it could.Application
These findings pose a great challenge to anybody trying to determine how much some product will be liked and if it will be preferred to another product. Consumers might like a product in one context and dislike it in another. They might slightly prefer the product in one context and not prefer it in another. Unless producers can figure out how to control the context in which the product is presented, they will have no idea of the acceptability of the product or if consumers will prefer it to another already on the market.
Producers would have no problem if they just made the best product of its kind. That is often times not possible or is prohibitively expensive. It must be remembered that cost is also a factor in consumer buying. However, the producer can make the best product in a category or class. So, for example, a car can be the best "economy car" but not the best "car." Making consumers think of a car as being in a particular category of car will prevent them from comparing a Volkswagen with a Porsche, so they still like the VW. Producers can also make a product appear to be unique, that is, in a category of its own. Because hedonic judgments seem to be relative, having consumers consider the product to be unique will prevent its comparison to other (possibly better) 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 more so in the not-so-distant past). This is particularly true if the individual has been exposed to items that are substantially better or worse than the original item. In addition, this exposure will influence the hedonic judgments of 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 the changes that can occur within an individual. So next time someone asks how much you like something, realize that "it depends."References
Arieh, Y., & Marks, L. E. (2003). Recalibrating the auditory system: A speed-accuracy analysis of intensity perception. Journal of Experimental Psychology: Human Perception & Performance, 29,
Beebe-Center, J. G. (1965). The psychology of pleasantness and unpleasantness.
New York: Russell & Russell. (Original work published 1932)
Conner, M., Land, D., & Booth, D. (1987). Effect of stimulus range on judgments of sweetness intensity in a lime drink. British Journal of Psychology, 78,
Dolese, M., Zellner, D., Vasserman, M., & Parker, S. (2005). Categorization affects hedonic contrast in the visual arts. Bulletin of Psychology & the Arts, 5,
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 & Psychophysics, 64,
Pol, H. E. H., Hijman, R., Baare, W. F. C., & van Ree, J. M. (1998). Effects of context on judgments of odor intensities in humans. Chemical Senses, 23,
Rota, L., & Zellner, D.A. (2005). Hedonic contrast in experts and non-experts: Categorization revisited. In J. S. Monahan, S. M. Sheffert, & J. T. Townsend (Eds.), Fechner day 2005: Proceedings of the twenty-first annual meeting of the International Society for Psychophysics
(pp. 291-296). Mt. Pleasant, MI: Central Michigan University Printing Services.
Zellner, D. A., Allen, D., Henley, M., & Parker, S. (in press). Hedonic contrast and condensation: Good stimuli make mediocre stimuli less good and less different. Psychonomic Bulletin & Review.
Zellner, D. A., Kern, B. B., & Parker, S. (2002). Protection for the good: Subcategorization reduces hedonic contrast. Appetite, 38,
Zellner, D. A., Rohm, E. A., Bassetti, T. L., & Parker, S. (2003). Compared to what? Effects of categorization on hedonic contrast. Psychonomic Bulletin & Review, 10,
468-473.Debra A. Zellner, PhD,
attended Muhlenberg College (PA) where she became a member of Psi Chi and received her AB in psychology. She earned her MA and PhD from American University (DC). After graduate school, she did postdoctoral training at the University of Pennsylvania and the John B. Pierce Foundation at Yale University (CT). While at the University of Pennsylvania, she worked with Dr. Paul Rozin and developed her current interest in food choice, perception, and hedonics. She is currently a professor of psychology at Montclair State University (NJ) where she is coadvisor of the local Psi Chi chapter. She has been a member of the governing bodies of the International Society for Psychophysics, the Eastern Psychological Association (EPA), and the Council on Undergraduate Research. She is a strong advocate for involving undergraduate students in research. All of the studies described in this article as well as most of her other publications have undergraduate coauthors.