Ethics approval

The experiment was reviewed and approved by the Central University Research Ethics Committee of the University of Oxford (reference number: MSD-IDREC-C1-2013-074), and complied with the Helsinki Declaration.

Experiment 1

In the first study, 18 non-smoking participants (12 females, 5 males, and 1 who failed to specify gender; age (mean ± SD) 34.7 ± 14.5 years, range 23 to 65 years) verbally agreed to participate in the study after the experimental procedure had been explained and their questions were answered. In total, the participants took four sips of a 12 year old single malt Scotch whisky with 40% alcohol volume from Dufftown, Scotland (The Singleton; Diageo plc, London, UK). The whisky was stored at approximately 19°C. Each sip of the whisky (approximately 20 ml) was taken in a different experimental condition, and was tasted neat (that is, without being diluted as would be typical in the UK) in a polystyrene foam (Styrofoam) cup of 177 ml capacity. All participants swallowed each sip, and after answering the questionnaire, used water as a palette cleanser before continuing with the next experimental condition. In three of the conditions, the participants were presented with a short audiovisual display, with one video designed to be ‘grassy’ , the second to be ‘woody’ , and the third to be “sweet” (Figure 1). In the fourth (control) condition, the participants sampled the whisky in the absence of any video.

Figure 1 Still frames taken from each of the three audiovisual displays designed to emphasize the attributes of the whisky in the laboratory-based pre-test (experiment 1). (A) Grassy, (B) sweet, and (C) woody attributes. Full size image

Participants were given a different sample of whisky to taste in each condition. This aspect of the experimental design meant that the participants were unaware of whether the whisky that they were tasting was the same from one experimental condition to the next. The ‘grassy’ audiovisual display included a close-up video of grass blowing in the wind and a background soundtrack, which consisted of a summer meadow soundscape with birds singing and the sound of the wind rustling through trees. The ‘sweet’ audiovisual display consisted of a dynamic image that alternated between red and black, based on previous research showing that red can influence our perception of sweetness [27]. This image was presented together with a soundscape created using the Yamaha Grand piano plug-in. This was passed through the Space Designer reverberation (reverb) unit set to 100% wet (amount of reverb) and 10% dry (amount of the original signal). The notes were based on the F scale pitched around C4 to C6 (midi notes 60 to 84) and superimposed with a sine wave-based synthesized tone generated in the Sculpture Modeling synthesizer plug-in in the same pitch (all the items used were obtained through Logic Pro X software, Apple, UK). This auditory piece was designed and has been used based on suggestive evidence about the association between high-pitched piano notes and sweet tastes [21, 28]. Finally, the ‘woody’ audiovisual display consisted of a video showing a close-up image of the grainy texture of a piece of wood, while the camera moved slowly across its surface. The soundtrack consisted of the sounds of leaves and twigs being crunched underfoot. All soundtracks were played at a comfortable listening level. The visual material was obtained by recording both grass and wood, and all the videos had a length of 13 seconds.

A within-participants experimental design was used. Participants were told that they would sequentially be given four small samples of whisky to taste. They were also informed that, for certain of the samples, they would view an audiovisual clip while tasting the whisky, whereas for one of the samples there would be no video. Participants had to rate various sensory (grassy, sweet, woody) and hedonic attributes (liking of both the Whisky and the audiovisual) of the whisky using 10-point scales ranging from 1 (‘not at all’) to 10 (‘very’). Participants made the ratings using a paper-and-pencil score sheet. The experiment was conducted in three groups of six participants, and the order was changed across groups. Participants were instructed not to smell (nose) or taste the whisky until they had been instructed to do so by the experimenter. Approximately 5 seconds after the audiovisual display started, the participants were instructed to first nose and then to taste the whisky. After each condition, the participants returned the sample to the experimenter and continued onto the next condition. Altogether, the experiment took about 15 to 20 minutes to complete.

Results

The results of this preliminary experiment are highlighted in Figure 2. The data were analyzed using a one-way repeated measures analysis of variance (ANOVA). In certain of the ANOVAs, the Greenhouse-Geisser correction was used to correct for sphericity (this applied to both Experiment 1 and 2). There was a significant difference in the ratings of the grassy attribute between the audiovisual conditions (F (2.095, 35.610) = 3.966, P = 0.026). Further pairwise comparisons were conducted using the least squares difference (LSD) correction. When the participants were presented with the grassy audiovisual display, they rated the whisky as being more grassy compared with the other conditions (P < 0.05 for all comparisons). The whisky was rated as grassier in the grassy condition (mean ± SD 5.38 ± 1.85) than in the control (4.33 ± 2.00), woody (4.05 ± 1.66), or sweet (4.05 ± 1.89,) conditions.

Figure 2 Summary of mean ratings in each condition for Experiment 1. Participants rated the whisky as (A) grassy, (B) sweet, (C) or woody, using a 10-point scale from 0 (not at all) to 10 (very). The error bars show the standard errors of the means. Full size image

Although the analysis did not reveal any significant difference between the audiovisual conditions in terms of the sweetness ratings, watching the putatively ‘sweet’ audiovisual resulted, on average, in the participants giving the highest numerical ratings on this attribute. The whisky was rated as sweeter in the sweet condition (4.72 ± 2.37) than in the control (4.20 ± 2.19), woody (3.83 ± 2.52), or grassy (4.33 ± 2.76) condition.

A significant difference between the woody ratings across the audiovisual conditions was documented (F (3, 51) = 8.068, P < 0.001). Pairwise comparisons showed that the participants rated the whisky as tasting significantly more woody when the woody audiovisual was presented compared with any of the other conditions (P < 0.005 for all comparisons). Specifically, the whisky was rated as woodier in the woody condition (6.66 ± 1.87) than in the control (5.16 ± 2.33), grassy (4.77 ± 1.73), or sweet (5.05 ± 2.53) conditions.

In summary, having participants view the various audiovisual displays did have an effect on their ratings of the whisky, with the exception of the sweet audiovisual display, although a non-significant trend in the expected direction was seen (this trend may well have reached statistical significance had a larger number of participants been tested). In particular, the grassy and woody notes were significantly more prominent after participants had viewed the appropriate audiovisual display. Taken together, the results of our first experiment suggested that viewing a short audiovisual display can exert a significant effect on people’s rating of the taste/flavor of a whisky.

By contrast, no significant differences between conditions were obtained in terms of participants’ liking of the whisky (Figure 3). Moreover, although analysis of the data failed to reveal any significant effect of the audiovisual displays, there was a borderline significant trend in the data toward participants liking the grassy more than the woody audiovisual display (P = 0.052).

Figure 3 Summary of participants’ mean ‘liking’ ratings in Experiment 1. After watching each of the audiovisual displays, participants used a 10-point scale (0 (not at all) to 10 (very)) to rate their liking for (A) the whisky and (B) each of the audiovisual displays. The error bars show the standard errors of the means. Full size image

Based on these promising initial findings, we decided to extend the results of this experiment to a much larger sample size (from 18 to more than 440 participants) and to test the participants under more ecologically valid multisensory conditions in our second experiment. The final layout of experiment 2 was based on the input of experiment 1, but included a design/creative element that was added to the new new multisensory environments.

Experiment 2

In total, 441 participants (165 female, 250 male, and 26 who failed to specify) took part in the study. The experiment was conducted at The Singleton Sensorium multisensory whisky tasting event held in Soho, London. All of the participants were volunteers recruited primarily by online advertisement and through media coverage of the event that appeared in the press in the weeks preceding the event. The advertisements included information about the general aim of the event (for example, assessing the influence of environmental cues on the taste of whisky), and the general procedure; namely, that the event would have three rooms, and that participants would go to each room while drinking the whisky. Because the experiment was conducted through a public event, the participants did not sign a consent form; however, the purpose of the study and the experimental procedure was explained, and only the participants who agreed to participate were offered a place in the event. Each participant was given a flat-bottomed glass containing approximately 60 ml of the same whisky used in experiment 1. The participants were also given a scorecard and pencil with which to enter their responses in each of the three rooms. The participants were then led, in groups of 10 to 15, through the three different rooms. The majority of the participants started in the Nose room, went from there to the Taste room, and ended up in the Finish room. Each room was designed so as to emphasize a particular attribute of the whisky. A different fragrance and soundscape was presented in each room. The visual design used was also very different in each of the rooms (Figure 4). The fragrances were created specifically for the event by Condiment Junkie.

Figure 4 Photographs illustrating details of the visual design used in the three rooms. These rooms were designed to emphasize specific attributes of the whisky: (A) grassy, (B) sweet, and (C) woody attributes of the whisky. Images are courtesy of the British Broadcasting Corporation on March 26, 2013 (http://www.bbc.co.uk/food/0/21864151). Full size image

Conditions

The Nose room This room had grassy turf laid on the floor, green-leafed plants placed around the walls, and green lights pointed at the white walls of the room. A croquet set had been placed on the ground, and there were three deck chairs in which participants were encouraged to sit. A blend of galbanum and violet leaf was used to create a fragrance that was reminiscent of fresh cut grass in the Nose room. The soundscape was recorded in a summer meadow, with birds singing and wind gently rustling the leaves of the trees. Occasionally, a sheep could be heard ‘baa-ing’ in the background.

Nill

The Taste room This room was illuminated by round red globes hanging from the ceiling in the centre of the room. The few scattered padded chairs in the room were also round, as was all the furniture and window frames. A round bowl of ripe red fruits was also placed conspicuously on the round table in the centre of the room. In fact, there was nothing angular in this room. This aspect of the experimental design was based on previous research showing that people generally associate sweetness with roundness rather than angularity [29, 30]. A blend of prunol and aldehydes was used in the Taste room. This fragrance was designed to be evocative of sweetness but not to be associated with a specific foodstuff (such as might have been the case had we used the smell of caramel, strawberry, or vanilla). Informal questioning of a number of participants revealed that the majority thought that ‘sweetness’ was the most appropriate of the four basic taste descriptors for the fragrance that was presented in this room. The soundscape included the high-pitched consonant sound of tinkling bells. Importantly, these sounds were presented from a loudspeaker situated in the roof to ensure the congruency between the pitch of the sound and its elevation in space (see Spence’s review [31] of the literature on crossmodal correspondences between, for example, pitch and elevation).

Nill

The Finish room The floor and walls of the Finish room were made of exposed wood panels. The room was dimly illuminated, and wooden boxes were stacked up on the floor on one side of the room. There were also several wooden chairs and a wooden bench. A leafless tree was placed in a corner. A large number of clocks were mounted on one of the walls. The fragrance used in the Finish room consisted of a blend of cedarwood and tonka bean, both associated with woodiness in the mind of the perfumier. The soundscape that was presented in this room included the sound of creaking timbers, a crackling fireplace, the occasional sound of someone walking through the dry leaves on the forest floor, and occasional low notes being played on a double bass (a wood instrument).

Experimental design

A within-participants experimental design was used. Once the participants arrived at the Sensorium event, they were directed to the bar situated on the first floor. There, they were instructed to wait until they had received a unit of the whisky in a glass. While the participants were waiting, the staff members organizing the event approached the participants and made sure that everyone had a questionnaire and a pencil. They also provided some general introduction to the background and purpose of the event/study. After the instructions had been given, a bartender provided each participant with a glass of whisky. With their glass in hand, the participants then proceeded to the first room, together with a guide, who provided them with a description of each of the rooms, and gave instructions about the completion of the questionnaire.

The participants were taken in groups of 10 to 15 through the three rooms, spending around 5 minutes in each room. The participants were first given a few moments to acclimatize themselves to the room, before rating how much they liked its atmosphere. The participants were then instructed to nose the whisky and to have a small sip before filling in the rest of the questions in the appropriate column of the questionnaire: the left column in the first room, the middle column in the second room, and the right-hand column in the third room. Finally, the participants were encouraged to move to the next room after having completed the relevant section of the questionnaire and asking any pertinent questions to their guide.

Given that the participants spent around 5 minutes in each room, the entire experiment took approximately 20 minutes to be completed. The scorecards and pencils were collected by one of the organizers from the participants as they left the third and final room, before they were escorted from the building.

Results

An ANOVA was conducted to assess any differences in participants’ ratings of the grassy attribute between conditions (that is, between the multisensory environments). A significant result was obtained (F (1.906, 819.627) = 182.154, P < 0.001), and pairwise comparisons (using the LSD correction) showed that when the participants responded in the Nose room, they rated the whisky as significantly more grassy (5.4 ± 2.30) than when they responded in the Taste (3.33 ± 2.08) or Finish rooms (3.59 ± 2.24) (P < 0.001 for both comparisons, see Figure 5). Furthermore, the participants rated the whisky as significantly more grassy in the Finish room than in The Taste room (P = 0.017).

Figure 5 Mean ratings for each of the three rooms in Experiment 2. Participants rated the whisky as (A) grassy, (B), sweet, or (C) woody on a 10-point scale ranging from 0 (not at all) to 10 (very). The error bars show the standard errors of the means. Full size image

Moreover, a significant difference between conditions (rooms) was also found with regard to participants’ ratings of the sweetness of the whisky ( F(2, 864) = 68.817, P < 0.001). Pairwise comparisons showed that when the participants responded in the Taste room, they rated the whisky as being significantly sweeter (6.08 ± 2.02) than when they responded in either the Nose (5.07 ± 2.08) or the Finish room (4.72 ± 2.13) (P < 0.001 for both comparisons). In addition, the participants rated the whisky as tasting significantly sweeter in the Nose room than in the Finish room (P = 0.003).

The ANOVA also revealed a significant difference between conditions with regard to the whisky’s woody aftertaste (F (1.257, 540.361) = 68.591, P < 0.001). When the participants responded in the Finish room, they rated the whisky as tasting significantly more woody (6.97 ± 4.8) than when they rated it in either the Nose (5.07 ± 2.11) or Taste room (4.77 ± 2.13) (P < 0.001 for both comparisons). Additionally, participants rated the whisky as significantly more woody in the Nose room than in the Taste room (P =0.002).

An ANOVA was performed to assess any difference between participants’ liking ratings for the whisky in the different rooms and resulted in a significant effect (F (1.929, 835.411) = 34.133, P < 0.001) (Figure 6A). In particular, the participants liked the whisky significantly more when they rated it in the Finish room (7.06 ± 2.06) than in either the Nose (6.4 ± 1.9) or the Taste (6.37 ± 1.89) room (P < 0.001 for both comparisons).

Figure 6 Summary of participants’ mean ‘liking’ ratings in Experiment 2. After sampling the whisky in each of the three rooms, participants used a 10-point scale (0 (not at all) to 10 (very)) to rate their liking for (A) the whisky and (B) each of the rooms. The error bars show the standard errors of the means. Full size image

We also assessed whether there were any differences in how much the participants liked the three rooms (Figure 6B). An ANOVA revealed a significant result (F (1.928, 830.951) = 120.227, P < 0.001). In particular, the participants liked the Finish room (7.89 ± 1.72) significantly more than either the Nose (7.28 ± 1.91) or the Taste (5.96 ± 2.35) room, and they also liked the Nose room significantly more than the Taste room (P < 0.001, for all comparisons).