Fiona Macpherson


Fiona Macpherson is Professor of Philosophy, and Director of the Centre for the Study of Perceptual Experience, at the University of Glasgow. She is Co-Director of CenSes: Centre for the Study of the Senses at the Institute of Philosophy, University of London. Her research is on the philosophy of mind and perception. She has written numerous articles in leading philosophy journals on the nature of perceptual experience and perceptual phenomena including cognitive penetration, cross-modal perception, synaesthesia, representation and phenomenal character. She has edited three books: Disjunctivism: Perception, Action, Knowledge (with Adrian Haddock) OUP (2008), The Admissible Contents of Experience, (with Katherine Hawley) Wiley-Blackwell (2011), The Senses: Classic and Contemporary Readings, OUP (2011). And she has three further volumes forthcoming:Hallucination: Philosophy and Psychology, (with Dimitris Platchias) MIT Press (2013), Representationalism (with Dimitris Platchias) MIT Press (forthcoming), Phenomenal Presence (with Fabian Dorsch and Martine Nida-Rumelin) OUP (forthcoming). Professor Macpherson is a vegan of twenty years standing and is keen to support and promote ethical, sustainable, vegan fine dining.

The theme of the workshop was how one can enhance the dining experience. A number of HCI researchers, psychologists, philosophers, and others working practically to create and manipulate dining activities discussed and experienced different aspects of eating, drinking, and dining.


Theory about the nature of experience featured prominently throughout the workshop and understanding it is essential for comprehending many of the interventions that one could make to alter people’s eating and drinking experiences. There are three essential points to note: (1) many senses contribute to the experience of flavour, (2) perceptual experience can be influenced by other experiences had at the same time, and (3) perceptual experience can be influenced by one’s beliefs and desires. The nature and range of the influences and interactions between the senses, experiences and cognitive states is in many cases far greater than one would have predicted on the basis of everyday experience; there are often surprising and unintuitive connections between the senses. I will elaborate and provide examples of each of the three points in turn below. In doing so, I will comment on how each leads to possibilities for altering—in some cases enhancing—the dining experience.

(1) Many senses contribute to the experience of flavour

First, consider the experience of the flavour of food and drink. The sense of taste involves the stimulation of the receptors on our tongue: our taste buds. Somewhat surprisingly, however, much of our experience of flavour seems to come from senses other than taste. Retronasal smell clearly contributes much to what we perceive to be the flavour of food. Retronasal olfaction occurs when air passes out through our noses, particularly from our mouths when we swallow. It is unlike orthonasal olfaction, which occurs when we breathe or sniff in air through our nose. At the workshop, Professor Barry Smith vividly demonstrated the effect of retronasal smell on flavour when he invited us to chew on a jellybean while our fingers held closed our nostrils. We couldn’t detect any flavour. However, when we let go of our nostrils the fruit flavour of the jellybean was suddenly and intensely experienced as being in our mouths—not in our noses—despite it being the retronasal stimulation that caused the change. People do not typically realise how much retronasal olfaction contributes to our perception of flavour because its influence is on what is sensed to be in the mouth. Often nothing is experienced as being an odour in the air or in the nose. When people complain that they cannot taste much when they have a cold they often do not realise that they are reporting not a change to their ability to taste with the tongue, but their ability to experience the flavour of food due to the diminished contribution of retronasal olfaction caused by a blocked nose. Titchner (1900) was perhaps the first to write in the scientific literature about this effect.

In addition to retronasal olfaction, many other sensory systems seem to play a part in the flavour that we report experiencing. The trigeminal system, which detects, for example, the capsaicin in chilli peppers and piperine in black pepper (both of which are experienced as spicy heat), has a role. The tactile system, primarily via detection of the texture and temperature of the food, has an influence too. For example, flavour intensity is reduced with an increase in thickness or viscosity of food and drink (Bult 2007, Cook et al. 2003) It has also been claimed that the temperature and texture of utensils used to deliver food into the mouth can have a similar effect (Piqueras-Fiszman et al. 2012). Perhaps even more surprising, the auditory system seems to play a part. Zampini and Spence (2004) discovered that the crunch sound of a potato crisp can affect how crisp and fresh it is reported as tasting, while Spence and Shankar (2010) discovered that even the sound of rustling and shaking a foil crisp bag when eating crisps affects the reported perception of freshness too. (For an overview of the contributions of the different senses to flavour perception see Delwiche 2004, Auvray & Spence 2008, and Zampini and Spence 2010.)

There are several philosophical and psychological questions that arise on account of these empirical results. One is whether it can really be shown that the senses other than taste have an effect on perceptual experiences of flavour, rather than just on non-perceptual beliefs or judgments formed about the flavour. For example, does the rustling of a crisp packet really change the experience of flavour or just the judgment one makes about how crisp and fresh the crisps are? This is a very difficult matter to determine empirically (Macpherson 2012). The answer is almost certain to be yes in some cases and no in others.

These results suggest that if one wants to affect experiences of flavour, or what people believe the flavour to be, then, in addition to altering the taste and smell of the food, one can manipulate many other senses. Whether such manipulations change the experience for the better or for the worse is an empirical matter and testing would have to be done on a case-by-case basis. However, the range of interventions possible is surely greater than one would have thought a priori.

A second question is what kind of experience occurs when flavour is affected by senses other than taste? Do experiences or processes in other modalities simply causally affect one’s flavour experiences that are fundamentally determined by taste, and perhaps retronasal olfaction? Or is the flavour experience simply the sum of experiences from more than one modality? Or is the flavour experience a new unique experience that amounts to something different from the sum of more than one experience? In other words, is there ‘multisensory integration’ in which two or more senses combine to produce one ‘superadditive’ experiential product that cannot be decomposed (or perhaps easily decomposed) into the combinations of each of the senses? In fact there are many more options that just these. What type of cross-modal experiences there are, and could be, is explored at length in Macpherson (2011).

These considerations suggest that if one wants to affect experiences of flavour then one may not be able to predict in advance what kind of change one might bring about by altering the input to one of the senses. For example, if one plays a certain sound to a person will one just cause the experience of flavour that a person would have had without the sound being played or would one create a new flavour experience? Would it be a flavour experience that one could bring about in other ways or would it be unique? Would the experience be more or less pleasant than (or the same as) the experience one would have had without the sound being played? There are no predictive rules that we know of to date that one can draw on to answer these questions and one must proceed by studying cases individually. Crisinel and Spence (2009 and 2010) are doing such work, for example, by mapping unobvious and unintuitive influences of sounds on tastes and flavours. Unfortunately, this probably means that hitting on interesting, novel, appealing, or desired flavour experiences might require many stabs in the dark or will have to draw on known effects reported in the extant psychological literature that have proceeded by a methodology involving much speculative conjecture about cross-modal influences.

A third question is whether the contributions to flavour perception by the various different senses make flavour perception more or less accurate (or neither). Again, it seems that different answers may be applicable to different cases. In many cases it looks as if information about the nature of what we place in our mouths is being gathered by many senses and all of it could contribute to a more accurate experience of the nature of what is in the mouth. However, sometimes there is clearly the possibility that this process will lead to error. For example, if one alters the sound of what someone is chewing by removing the lower frequencies and enhancing the higher frequencies, and one plays the altered sound to the chewer while they are chewing, then he or she will judge the crisps they are eating to be fresher than they otherwise would. However, in this case, the auditory information is not reflective of the true chewing sounds the crisps would illicit and so chewers are being fed incorrect information.

A different sort of case would be one in which the addition of accurate information about a food or drink affected one’s experience of it in a way that led us to think that the resultant experience was less accurate. There may be such cases. Consider the experiment performed by Nguyen et al. (2001, reported in Valentin et al. 2006) where subjects were asked to compare a sucrose-vanilla mixture with a sucrose-lemon mixture. French subjects judged the vanilla mixture sweeter than the Vietnamese subjects and vice versa. This effect is thought to stem from the common paring of vanilla and sweetness in French cuisine and the common pairing of lemon and sweetness, through frequent ingestion of lemon soft-drinks in Vietnamese culture. This is some evidence— although clearly not conclusive evidence for other interpretations of these results are possible—in favour of the conclusion that at least one of the groups— the French or the Vietnamese—is judging each mixture’s sweetness incorrectly.

If it is possible to add extra (accurate or inaccurate) information to make someone’s experience or judgment of flavour inaccurate, then this raises moral and aesthetic questions about the nature of the interventions it is permissible or desirable to make on a person’s gustatory experience. To make such questions vivid, consider the following thought experiment. Suppose that that it were possible to make food that is long past its best taste as if it were at its height of freshness and nutritional value by playing certain music to people who were eating it. In what circumstances would it be permissible to play people this music when eating the food? On the one hand, one might think that it would be immoral if a restaurant used up its left overs by fooling people into thinking that the food was fresh. On the other hand, suppose a restaurant explicitly had an eco-friendly policy of not wasting food, and the food that was past its best still had some nutritional value and would not do people any harm. If the customers were informed that this was the food that they were going to be eating, and what the effects of the music would be, then perhaps this would be a morally positive thing to do. But, there are cases in which it is difficult to say whether what one is doing is right or wrong. Imagine people starving in the third world, or indeed on the streets of Britain. If feeding them food that is long past its best, would save their lives, but it is not food that a person could ever stomach eating without the presence of the music, would it be moral to provide such food together with the music, either in the condition where the people knew of the effect of the music or the condition where they did not? I do not know.

The deception involved in some of these moral cases is connected to issues concerning aesthetic value. One way is via the link that some people believe exists between aesthetic value and truth. If one can increase the hedonic value of someone’s experience but in a way that relies on deception or producing nonveridical experience, then some people would think that such experiences were devalued aesthetically to the extent that a lack of truthfulness was involved in them.

Figure1: the ambiance at John Salt restaurant where the workshops was held

Figure1: the ambiance at John Salt restaurant where the workshops was held

Another important issue that is brought to the fore by one of the examples above is the culture specific influences that one sense may have on another or that one experience may have on another. We saw that the French and the Vietnamese reacted differently to the presence of vanilla and lemon. In today’s multicultural world, must we develop interventions designed to take account of a person’s cultural background? Even if we could and we did, this would not overcome the more general worry that such cases raise. The worry is that the influence of one sense on another, or one experience on another, is not predictable or not controllable across people due to interpersonal differences. This would mean that it may not be possible to create uniform experiences for one’s diners in a restaurant. One’s customers past experiences may be as much responsible for their flavour experiences as the food and the ambiance that one provides for them.

Not only can past experience create individual differences but one’s physiological make-up can too. Some people are “supertasters”. This means that they are more highly sensitive to bitter tastes either due to the larger number of taste buds that they have on their tongue or because they carry a gene that makes their taste buds more sensitive to the bitter taste of a chemical called 6-n- propylthiouracil (also known as PROP). While being a supertaster sounds positive, in fact it may mean that supertasters have less pleasant, more bitter experiences than medium tasters and non-tasters. At the workshop we had the chance to discover whether we were supertasters by tasting paper strips with PROP on them. Again the existence of these individual differences implies that affecting and controlling people’s dining experiences will be very difficult to do.

(2) Perceptual experience can be influenced by other experiences had at the same time

Thus far I have been discussing the nature of flavour experience and influences on it. However, as I have noted in doing so, we know of a huge number of cases in which the experience that one has in one sensory modality is affected by the experiences that one has in other modalities. All the above issues that were discussed with respect to flavour perception therefore apply to all elements of our experience. In one respect, the person who is looking to intervene in our dining experience may be excited by this prospect. The lighting in a restaurant may affect your experience of the colour of your tablemat, which in turn may affect the way the soup tastes to you, and in turn the way the music sounds to you. Thus the ways in which one can influence and affect someone’s experience may be nigh limitless. However, this comes with an enormous downside. If one composes a certain music that one thinks will enhance the soup, does one need to check that the music will have that affect on the soup when the diner experiences the colour of the tablemats to be the way that they do, given the lighting? And given that some people are colour-blind, might one provide them with awful experiences of the soup on account of their experience of the colour of the tablemats? How can one keep track of these various interactions, particularly, when we have seen how unintuitive and unpredictable such effects can be?

(3) Perceptual experience can be influenced by one’s beliefs and desires

Figure 2: an advert seen in Glasgow November 2012. Is this an attempted case of cognitive penetration: attempting to change the way the wine tastes by changing the drinker’s attitudes—in this case about themselves?

Figure 2: an advert seen in Glasgow November 2012. Is this an attempted case of cognitive penetration: attempting to change the way the wine tastes by changing the drinker’s attitudes—in this case about themselves?

Very similar issues arise, indeed are amplified, when we consider the existence of cognitive penetration (Macpherson 2012, Stokes 2012). We have reason to believe that one’s beliefs, desires, expectations and goals can affect the nature of the experience that one has. The person looking for ways to affect the experience of a diner may once again be excited by the prospect of these further ways and means of intervening in people’s dining experience. The existence of cognitive penetration opens up the possibility that one can affect the dining experience by creating beliefs, desires, expectations or goals prior to the diner eating. This may involve the nature of the various elements of their experience in the restaurant before they eat: the ambiance, the smell, lighting, the nature of the waiters and waitresses, the furnishings, and so on. However, it may also mean that there are opportunities to affect people’s experience when dining even before they arrive at the venue (which may, of course be a traditional restaurant, but may also be an impromptu pop-up venue, a theatre, a cinema, or any number of places where one may dine). This means that the marketing of the restaurant or venue, and the expectations that it creates, may be crucial, in addition to the process of making a reservation.

In addition, one might choose to intervene in novel ways before the diner arrives at the restaurant. One example of this that was discussed at the workshop was Heston Blumenthal’s “Like a Kid in a Sweet Shop” project developed in association with “The Neighbourhood”, a creative studio (see The Neighbourhood 2012). People making reservations for the restaurant were presented with unique digital content based on the theme of a sweet shop to peruse which, in part, informed them about Blumenthal’s Fat Duck Restaurant and created expectations about their experience. It was designed to “whet their appetite”. Themes and elements presented in the digital content were echoed and presented during the time the diners were at the restaurant, finishing with a bag of sweets as the final course of the meal.

Figure 3: One man’s meat is another man’s poison: advert at Prestwick airport August 2012 for a Scottish “breakfast of champions” for holidaymakers.

Figure 3: One man’s meat is another man’s poison: advert at Prestwick airport August 2012 for a Scottish “breakfast of champions” for holidaymakers.

The beliefs, and influences of those beliefs, on a person’s experience may fall under generalisations that apply to many, thus allowing for predictable interventions on a person’s experience. However, I suspect that in many cases the phenomenon of cognitive penetration amplifies individual differences and the lack of control that one may have in determining the nature of a person’s experience. For example, in “When restaurants get ridiculous” a Guardian Word of Mouth blog (Naylor, 2012) that participants at the workshop were asked to read in advance, the author admitted to often being uncomfortable in restaurants where out of the ordinary things were done, in particular when he was asked to do out of the ordinary things. This provides another example of the fact, to use a sublunary example, that one’s man’s meat may be another man’s poison. One intervention may end in gastronomic reverie and a night never to be forgotten for one person; embarrassment, dislike and distaste might result for another.

This lack of control over the outcomes of the interventions that one might make on a diner feeds into the final issue that I will address in this paper. It is the issue of what one wants to achieve by intervening in the diner’s experience. This issue was raised by Charles Spence in his presentation at the workshop. Spence first noted that people have done very many things to change people’s dining experience. For example, he noted that in one restaurant one can change the colour of the pod-like environment in which one and those at one’s own table sit. But he asked what was the point of such an intervention in the dining experience? He suggested that there was no scientific evidence that would make one think that doing this would specifically change the diners dining experience, rather than just their general experience of, say, being in a public place. In doing so he brought our attention to the fact that one can change a diner’s experience in many gimmicky ways. One might ask one’s diners to be naked, or to sing a song before dinner, or to only come with their grandmother or grandchild, and so on. Is this the kind of intervention that we wish to consider making? Is anything creating anything that is vaguely aesthetic or memorable, a good thing to do to create a novel dining experience? We can distinguish this question from that raised in the previous paragraph by focusing in only on positive experiences that people enjoy. Is any positive, unusual experience one that we should wish to create for diners?

Figure 4: Naylor (2012) discusses a dish served at John Salt restaurant by chef Ben Spaulding that is served on a brick that we tried at the workshop. He says, “I would be plagued by the nagging doubt that, behind the swing doors, the kitchen staff were sniggering into their Thermomix. ‘Look at that knobhead, he's actually licking the brick.’”

Figure 4: Naylor (2012) discusses a dish served at John Salt restaurant by chef Ben Spaulding that is served on a brick that we tried at the workshop. He says, “I would be plagued by the nagging doubt that, behind the swing doors, the kitchen staff were sniggering into their Thermomix. ‘Look at that knobhead, he’s actually licking the brick.’”

One might hope that there is a special value to be gained by not being gimmicky for gimmicky’s sake. Indeed, one might think that if one want’s to affect the dining experience specifically, not just the extraneous parts of one’s experience that exist when one dines—parts that might exist when one does not dine but carries out other activities—then one should want to focus in, at least as much as is possible, on affecting the experience specific to dining and in a way that to the best of one’s knowledge, and to the best of the knowledge of the scientific and philosophical communities knowledge, enhances and directly affects that experience. Thus one should try to affect the person’s dining experience based on known interactions and effects. However, as we have seen, finding what these are, and finding ones that are not affected by intercultural and interpersonal differences will be a very difficult task.

I hope that this paper about the issues that govern why, how and when one might or might not intervene on the eating and drinking experience of diners will provide technologists, psychologists, chefs and restaurateurs food for thought.


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