How do you know what foods you like? Simple. It’s that inner voice, that warm feeling, that ….. subjective positive ‘something’ whenever certain foods are thought about or mentioned or available. Tapping into this subjective state is, at first sight, relatively straightforward. If I want to know which food you like or which of several you prefer, I can ask you. Sensory and consumer scientists do this all the time. You can be asked to provide a rating of liking for a food, or be asked to rank foods in order of preference, or simply choose one food out of several to consume. Each of these approaches accesses some aspect of what you are feeling towards the food at that moment. They reflect the subjectivity of your preferences.
Deriving subjective measures is sometimes
seen as a problem, mainly because we often equate objectivity with reliability
and hence see subjective responses as somehow inferior and unreliable. This in
turn has led to searches for objective measures of subjective states, the most
recent of which is brain imaging, typically via fMRI techniques. While it is
perfectly possible to show brain correlates of positive and negative emotions
associated with foods, there is the rather important question of what is used
to validate the brain response. That’s right …. a subjective report.
Turning to technologies such as MRI is understandable because it is a natural assumption that technology solves problems. Yet, to help us understand likes and dislikes there are some far more basic questions that need to be addressed. Why, for example, when a person provides a high rating of liking for a food in a sensory test does this often fail to predict what they will purchase at a later date? At one level, the answer is obvious. Eating a small piece of confectionary in a test situation – even if it is judged as very delicious (a 10!) – differs from real life eating in that the context is artificial, the amount is unrealistic, the influence of brand is often absent, and you are removed from all those factors that are influential in making choices.
Studies in the psychology of decision-making have shown repeatedly that situational factors including one’s mood at the time, and a variety of environmental influences (including, for example, the weather), are incorporated into decisions. These influences are not only often unrelated to underlying preferences, but they also operate largely outside of our conscious awareness. In other words, your selection of Biffo Brand Baked Beans may be as much about the fact that it is cold outside as it is about your likes and dislikes. This is not good news for a food industry wanting to predict consumer behavior from the basis of sensory tests. It doesn’t mean that the sensory tests are useless, merely that they serve only to make sure the sensory properties are within acceptable parameters.
Unfortunately, there’s more bad news. It
is widely assumed that attitudes, beliefs and emotions, including preferences,
precede behaviours: I wear my seat belt because I value road safety; I smile
because I am happy; I choose food A over food B because I prefer food A. But none
of these things are necessarily true, at least not all of the time. Let’s take
emotions. More than a century ago, the pioneering psychologist William James
wrote about expression as being central to the experience of emotions, and
raised the possibility that we might experience subjective emotions as a consequence of monitoring our
physiological and behavioural responses to situations. According to James, it
wasn’t at all clear that the fear we experience when being chased by a bear
(those were dangerous times!) is not due to the fact that we feel our heart
racing, and our palms sweating, rather than vice
versa. A somewhat similar view was proposed decades later by another
psychologist, Stanley Schacter, who showed that whether a drug makes you
anxious or happy can depend entirely on the context in which its effects are
Most recently, a variant of this idea –
the facial feedback hypothesis – was proposed to explain how facial expressions
might not only reflect emotions, but also produce them. This hypothesis was
tested in an ingenious experiment in which facial muscles were manipulated by
having the participants hold a pen between their teeth, parallel to the mouth,
forcing the facial muscles into a smile. Compared to a control group who simply
held the pen in their hand, these participants rated a set of cartoons as
funnier. In effect, forcing a smile produced the same type of mood state usually
thought to produce smiles.
What does all this social psychology have to do with food likes and dislikes? A recent study has confirmed a number of findings from the past decade that the decisions and choices that we make play an active role in producing the preferences that we assume lead to those choices in the first place. Alos-Ferrer and colleagues  asked groups of university students to rate their liking for holiday destinations. The experimenters then selected four of these: two were moderately, but equally liked; one was liked less than these; and another was liked more. Each of the moderately liked destinations was then paired with one of the others, and the students were then presented with these pairs and asked to pick one from each pair. This produced a situation where one of the equally liked destinations was paired with a less liked destination (and therefore likely to be picked) and the other was paired with a more liked destination (and therefore unlikely to be picked). In other words, the students were forced into choosing one alternative and rejecting one alternative, when both were previously rated equally liked. When the students were once again asked to rate the destinations, the researchers found that the chosen destination was now preferred over the one that wasn’t chosen.
One explanation for this effect – now shown
in several studies using different types of stimuli – is that increases in
liking are based on observations and interpretation of our own past behavior.
For example, we might infer from that fact that we have already chosen an
alternative that that alternative was previously valued, and this in turn
creates a biased view of the alternative’s current value. An account of choices
was also provided by Festinger’s cognitive dissonance theory, first proposed in
the 1950s. Festinger suggested that a choice between equally valued
alternatives creates an unpleasant psychological tension (or dissonance) that
is relieved when we decide that one alternative is actually superior to the
Both of these views rely on recall of past choices. However, in another recent report in which choices determined preferences for odours , the participants were asked to recall their choices. It was found that preference changes did not rely on an explicit recall of which odour was chosen and which one wasn’t. This suggests strongly that the change is preference was not simply a way of justifying the choices that had been previously made. Another explanation not requiring an explicit memory of choices comes from studies showing that neutral stimuli used as cues become more valued when they signal either the availability of choice  or are associated with an evaluation . Thus, choice seems to be intrinsically rewarding and so that anything associated with choice becomes preferred.
This being the case, should we be relying
on choices or subjective measures of food preferences? From the point of view
of assessment of consumer likes and dislikes, it is clear that the process of
forcing a choice induces a preference. We might expect then that sometimes
choices and preferences are highly correlated and sometimes not, depending on
how such tests are conducted. But is this any different from what we all
experience in a supermarket? Probably not, but recall that choices can be
decided by aspects of the context that may be unrelated to the product chosen. Thus,
those situational factors that momentarily influence the choices that you make
now become highly influential in shaping your longer-term preferences. This
does not mean that either choices or measures of preferences are meaningless,
just that they are more complex than we generally assume.
1. Alos-Ferrer, C., Granic, D-G., Shi, F. & Wagner, A.K. (2012). Choices and preferences: Evidence from implicit choices and response times. Journal of Experimental Social Psychology, in press.
2. Coppin, G., Delplanque, S., Cayeux, I., Porcherot, C. & Sander, D. (2010). I'm No Longer Torn After Choice : How Explicit Choices Implicitly Shape Preferences of Odors. Psychological Science, 21: 489-493.
3. Gast, A. & Rothermund, K. (2011). I Like It Because I Said That I Like It: Evaluative Conditioning Effects Can Be Based on Stimulus-Response Learning. Journal of Experimental Psychology: Animal Behavior Processes, 37: 466-476.
4. Leotti, L. A. & Delgado, M.R. (2011). The Inherent Reward of Choice. Psychological Science, 22: 1310-1318.