Sound bites: how sound can affect taste

The senses are a vital source of knowledge about the objects and events in the world, as well as for insights into our private sensations and feelings. Below is an excerpt from Art and the Senses, edited by Francesca Bacci and David Melcher, in which Charles Spence, Maya U. Shankar, and Heston Blumenthal look at the ways in which environmental sounds can affect the perceived flavour of food.

Charles Spence and Heston Blumenthal conducted two experiments together with the members of the audience who attended the opening session of the ‘Art and the Senses’ conference held in October of 2006 that were designed to examine whether (and/or to demonstrate that) environmental sounds would influence people’s perceptions of the foods that they were eating. In the first experiment, 40 audience members were asked to taste two samples of ‘bacon and egg’ ice cream, one after the other, and to rate the flavour of each scoop. They were instructed to rate the relative strength of the bacon and egg flavours by making a mark on a scale provided on a sheet of paper. A different soundtrack was played in the background while the members of the audience consumed each of the ice creams: one soundtrack consisted of what sounded like bacon sizzling in a frying pan, while the other consisted of the clucking sounds of farmyard chickens. The ice cream was served with the farmyard soundtrack and a yellow plastic spoon (e.g. consistent with the colour of eggs) while the other sample was presented with a blue spoon.

The results showed that the audience rated the ice cream tasted in the presence of the sizzling bacon soundtrack as having a significantly more bacony flavour than the ice cream sample that was tasted in the presence of the farmyard chicken sounds. Interestingly, however, both scoops of ice-cream had come from the same batch—that is, the flavours were actually identical. These results show that auditory cues can be used to bias people’s perception of the relative strength of two competing flavours in a food.

More generally, it should be noted that the disambiguation of the flavour of a food dish can be achieved by a number of means: either visually, by changing the colour of the food, verbally by means of labelling, by presenting pictures or other cues on the packaging, and/or by the presentation of auditory cues, as described in the present study. Furthermore, even saying the word ‘cinnamon’ has been shown to activate the olfactory cortex (i.e. the part of the brain that processes smells; see Gonzalez et al. 2006). Playing the sizzling bacon soundtrack at the ‘Art and the Senses’ conference may therefore have influenced the audience’s perception of the bacon flavour in the ice cream simply by making them think of bacon. All provide putative explanations of how listening to the sound of frying bacon might make bacon and egg ice-cream taste more bacony! It is at present an open question as to whether simply writing the word bacon on the screen in the front of the auditorium would have had the same effect. The soundtracks were presented at a clearly audible level in this study and some of the audience members could feel that their flavour perception was being changed by the soundtrack; a few even tried to override this form of auditory manipulation by repeating the word ‘bacon, bacon, bacon. . .’ to themselves like a mantra when listening to the farmyard chickens clucking away, but to little avail. One suggestion is that environmental auditory stimuli may activate superordinate knowledge structures and hence prime related stimuli.

In a second study, 33 members of the audience were asked to taste and rate two oysters in terms of their pleasantness and intensity of their flavours. One oyster was served in the shell from a wooden basket (of the type that one commonly sees at the seaside). The other oyster had been removed from the shell and was served in a petri dish instead. The first oyster was served while the audience listened to the ‘sounds of the sea’ soundtrack in the background (this consisted of the sound of seagulls squawking and waves crashing gently on the beach), the second while they listened to the ‘farmyard noises’ used in our first experiment. The results revealed that the audience rated the oyster that they had consumed while listening to the ‘sound of the sea’ as tasting significantly more pleasant than the oyster that had been tasted while they listened to the farmyard noises instead. Interestingly, however, no such effect was found for the intensity ratings. That is, changing the sound had no effect on people’s perception of the intensity of the flavour of the oysters.

Taken together, the results of these two experiments, conducted at the ‘Art and the Senses’ conference, highlight just how dramatically environmental sounds can influence (or bias) people’s perception of the foods they consume. Interestingly, these results led directly to the introduction of the ‘Sound of the Sea’ seafood dish on the tasting menu of The Fat Duck restaurant in Bray. With this dish, diners are presented with a plate of food that is reminiscent of a beach (with foam, seaweed, and sand all visible on their plate). The diners are also presented with a mini iPod hidden inside a sea-shell, with only the earphones poking out. The diners are encouraged to put on the headphones (whereupon they hear the ‘sounds of the sea’ soundtrack) before starting to eat the dish placed in front of them. The response of diners on the tasting menu has been very positive. The diners appear to really enjoy the dish. In fact, it has become a signature dish at the restaurant. The dish appears to work at several levels: by getting the diners to think about the role of hearing in eating and by helping to illustrate the importance of sound to the appreciation of food. Second, we believe, on the basis of the evidence reported here, that the dish is so successful because the soundtrack serves to intensify the flavour of the dish. That is, it heightens the flavour. It is also worth noting that wearing the headphones has the originally unanticipated additional effect of concentrating the diners’ attention on the dish since it becomes difficult to converse with one’s dinner partners while listening to the seaside sounds.

Professor Charles Spence is the head of the Crossmodal Research Laboratory based at the Department of Experimental Psychology, Oxford University. Maya U. Shankar is also in the Department of Experimental Psychology at Oxford University. Heston Blumenthal is a well-known chef and owns The Fat Duck Restaurant in Bray, which holds three Michelin stars and was voted the best restaurant in the world in 2005.

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