The highly discriminating consumer

In the sensory evaluation of foods or drinks, good practice dictates that the type of question being asked will determine both the method of evaluation and the sort of panelist that is required. To analyze the different odours, tastes and textures within a complex food requires considerable training in vocabulary and use of rating scales. One by-product of such analytical training is that the individuals become very sensitive to variations in the intensity of product attributes and, by extension, to differences between samples on these attributes. In effect, trained panelists are good at seeing the signal amid the noise of lots of other product qualities.

In contrast, untrained consumers are highly variable in their use of sensory terms and their assessment of attribute intensities. It is not that you can’t ask consumers about product attributes, but rather that you’ll end up with a highly variable set of numbers if you do. An implicit assumption has been that because of such variability, consumers are unlikely to be sensitive to variations between similar products or versions of products, if those differences are quite subtle.

But what if discrimination isn’t only about perceptual sensitivity? Students of Signal Detection Theory (and who isn’t?) will know that decisions are based not only on perceptual sensitivity but also on one’s criterion – essentially, one’s willingness to report something as being present or not. This is often referred to as response bias, and signal detection and discrimination methods measure it independently of sensitivity.

We might want to consider also the reasons why we might want to discriminate between different products or samples. A few years ago, my flavourist colleague Leslie Norris and I were sitting in her kitchen discussing whether or not any improvement could be made in the way that wineries tested for the presence of cork taint in batches of wine. At that time, in order to reduce the amount of tainted wine that reached the consumer, highly trained panels were used because these individuals could be made very sensitive to the tainting compound TCA (trichloranisole) through their training. But then we had a shared “aha” moment. Trained panels were being used to ask a question that was primarily of relevance to consumers. What if these panels were too sensitive, potentially rejecting batches of wine that consumers would find perfectly acceptable? The outcome of this was a method – which we termed the consumer rejection threshold – that specifically used consumer preference responses [1]. In this case, consumers were, by definition, sensitive enough, but not too sensitive, to achieve the aim.

More fundamentally, perhaps, recent research has suggested that consumers might in fact be highly discriminating, at least partly as a function of not being trained. Analytical panelists become skilled at ignoring their emotional responses to the samples that they evaluate, with the (probably correct) assumption that analytical and hedonic approaches are necessarily antagonistic. If discrimination were purely a perceptual process then we might argue that removing emotion from the equation is appropriate.

In fact, a case can be made that ignoring emotional responses actually impairs discriminative ability. Several studies over the past decade suggest that engaging and utilizing emotions may be critical to discrimination. An evaluation procedure known as the authenticity test has sometimes been shown to be superior to analytical methods at detecting product differences. The essence of this test is that the emotions of regular consumers of a product are manipulated by exposing them to a story that has a strong negative implication for their product. For example, in one study, regular consumers of Danish milk were told that foreign milk imports might be introduced onto the market [2]. Instead of being asked to find the different sample or the sample with the highest level of some property, the consumers are asked to pick the authentic (that is, Danish) sample. In this case, the milk samples differed according to feed type and storage time, and the authenticity test revealed that both factors had an impact on milk flavour.

Why do emotions improve discriminability? One persuasive argument is that eliciting emotional states allows access to the otherwise “unconscious”, implicitly learned information about the product that all regular consumers possess. In other words, we are all experts in respect to the flavour and other sensory characteristics of our favourite products, even if we do not possess explicit awareness of such knowledge or a detailed sensory lexicon [3]. This explanation (also called the mood as Information hypothesis by social psychologists) proposes that negative emotions focus attention on deviations from the implicit memory of product attributes. Negative emotions are necessary because they probably act as signals that something is wrong. In effect, we monitor our own mood to infer that there is a problem. In turn, this evokes cognitive effort to search for causes of the “problem”. It becomes adaptive, therefore, to pay attention to details. In terms of the authenticity test, it is the unauthentic product that raises the alarm.

The ability of the authenticity test to induce emotional arousal and improve discrimination is also consistent with what we know from psychology and neuroscience about emotion and attention. It is clear that the brain allocates attention to stimuli as a function of their emotional significance. Thus, using emotional priming stimuli (a smiley face will do) in a detection task produces improved detection of very brief neutral stimuli that follow it. Similarly, emotional facial expressions command attention much more quickly than other sorts of stimuli, as do stimuli that have previously been paired with a reward.

Another way of considering the relationship between emotion and discrimination is to think about the later as a choice situation. Choices and preferences are intimately linked (see for example, Taste Matters website or blog, August, 2012: Choosing to like of liking to choose). Making a discrimination is of course making a choice on some basis. Why pick one thing over another? If an emotion is crucial to the decision, then the decision has motivational implications. In some cases, discrimination between alternatives allows selection that contributes to survival, such as when we choose a high-energy food over a low energy version.

Invoking a motivational explanation of discrimination leads to some interesting predictions. It suggests, for example, that we might be better at discriminating tastes or flavours when we are hungry …. but only for those substances that are likely to reduce hunger.  Cattle, sheep, horses and rabbits select and eat more of forage cut later in the day, when sugars are highest. We, too, should be better at discriminating sweet - but not bitter - tastes of different intensities before lunch.

                                                                                                                                   

1.         Prescott, J., et al., An estimate of the “consumer rejection threshold” for TCA in white wine. Food Qual. Pref., 2005. 16: p. 345-349.

2.         Frandsen, L.W., et al., Feelings as a basis for discrimination: Comparison of a modified authenticity test with the same–different test for slightly different types of milk. Food Qual Pref, 2007. 18: p. 97-105.

3.         Koster, E.P., Diversity in the determinants of food choice: A psychological perspective. Food Qual Pref, 2009. 20: p. 70-82.

Choosing to like or liking to choose?

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 experienced.

 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 [1] 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 other. 

Both of these views rely on recall of past choices. However, in another recent report in which choices determined preferences for odours [2], 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 [3] or are associated with an evaluation [4]. 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.