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The role of expectancy in sensory and hedonic evaluation: The case of smoked salmon ice-cream

Martin R. Yeomans a, * , Lucy Chambers a , Heston Blumenthal b , Anthony Blake c

a Department of Psychology, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QH, UK b The Fat Duck Restaurant, Bray Oxford, UK c Firmenich Research, Geneva, Switzerland

a r t i c l e i n f o

Article history:Received 15 August 2007Received in revised form 7 February 2008Accepted 24 February 2008Available online 4 March 2008

Keywords:FlavourHedonicsExpectancy

a b s t r a c t

Our experience of avour involves integration of multiple sensory inputs, and the hedonic evaluation of this complex avour experience is important in determination of food choice. The appearanceof food alsogenerates expectations about food avour, and past work suggests that these expectations if conrmedenhance the avour experience. What is less clear is what happens when cues prior to ingestion predicta avour whichis in marked contrast to theactual avour characteristics. To test this, we conducted threeexperiments where expectations about food avour were generated by plausible but inaccurate foodlabels for a highly novel food, smoked-salmon ice-cream. In Experiment 1, the experience of the foodin the mouth generated strong dislike when labelled as ice-cream, but acceptance when labelled as frozensavoury mousse. Labelling the food as ice-cream also resulted in stronger ratings of how salty andsavoury the food was than when labelled as a savoury food. Experiment 2 conrmed these ndings,and also found that an uninformative label also resulted in acceptable liking ratings. Experiment 3 explic-itly tested the effect of labels on avour expectation, and conrmed that the ice-cream label generatedstrong expectations of a sweet, fruity avour, consistent with the visual appearance of the ice-cream,but in marked contrast to the avour of salty sh. As in Experiments 1 and 2, liking was minimal when

the food was tasted after the ice-cream label condition, but liking was acceptable in the other label con-ditions. These data show that the contrast between expected and actual sensory qualities can result in astrong negative affective response and enhancement of the unexpected sensory qualities.

2008 Elsevier Ltd. All rights reserved.

1. Introduction

Although the senses are anatomically separate, they rarelyoperate independently since the majority of stimuli in the environ-ment stimulate multiple senses. The increased recognition that oursensory experience reects integration of these multiple sensoryinputs has been applied to many experiences, most notably inthe current context to our experience of food avour (e.g., Delwi-che, 2004; Keast, Dalton, & Breslin, 2004; Small, Jones-Gotman, Za-torre, Petrides, & Evans, 1997 ). Although the experience of thesensory qualities of a food are often described in terms of how it‘‘tastes”, in practice this experience of avour is a complex interac-tion between multiple sensory experiences. Arguably, multi-sen-sory integration may be at its most extreme in the case of avour perception since few other experiences offer the opportu-nity for concomitant stimulation of all the major senses: gustationthrough the ve primary tastes, olfaction through both ortho- andretronasal stimulation of olfactory receptors by volatile com-

pounds released from food, mechanoreception contributing toour perception of texture and providing information on tempera-ture, pain arising from oral irritants and hearing that results fromsounds and vibrations coming from the mouth contributing toour perception of aspects of texture. The focus of the present paperis on a further aspect of the multi-sensory experience of avour,how expectations about food avour arising from visual and cogni-tive cues prior to ingestion modify our hedonic and sensory expe-rience of the avour of food in the mouth.

The visual appearance of a food is well known to inuence a-vour recognition. Thus many studies have shown that the presenceof a congruent colour enhances the ability to identify food anddrink stimuli, relative to presentation of the same stimuli withouta colour cue or with an incongruent colour ( Dubose, Cardello, &Maller, 1980; Stillman, 1993; Teerling, 1992 ). Further evidence of cross-modal associations within food-related stimuli involving vi-sual cues comes from studies of interactions between visual andolfactory stimuli. For example, when a white wine was colouredred, the sensory descriptors applied to the odour of the wine wereconsistently terms used normally for red rather than white wine(Morrot, Brochet, & Dubourdieu, 2001 ). Thus, in the absence of

0950-3293/$ - see front matter 2008 Elsevier Ltd. All rights reserved.doi:10.1016/j.foodqual.2008.02.009

* Corresponding author. Tel.: +44 1273 678617; fax: +44 1273 678058.E-mail address: martin@sussex.ac.uk (M.R. Yeomans).

Food Quality and Preference 19 (2008) 565–573

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appropriate visual cues, the actual olfactory quality of the wine hadlittle impact on the way in which the wine odour was described,with instead the colour predominating. Likewise, explicit detectionof both food-related and non-food odours was enhanced when theodour was presented alongside a congruent picture (e.g., ice-creampicture presented with vanillin, see Gottfried, & Dolan, 2003 ), andlikewise speed and accuracy of odour detection was faster for con-gruent odour-colour pairings (e.g., strawberry odour and pink col-our) than for incongruent pairings ( Luisa Dematte, Sanabria, &Spence, 2006 ). One explanation for these effects is that the visualcue sets up an expectation of the avour to be experienced in themouth as a consequence of past associations between the visualappearance and perceived avour of similar food stimuli. Indeed,it has been argued that such associations are likely to be memor-ised without any explicit attention or learning ( Koster, Prescott,& Koster, 2004 ), highlighting further the key role of memory indeveloping food-based expectancies (Mojet, & Koster, 2005 ).

An important methodology in examining the role of expecta-tions in determining our experience of avour has been to manip-ulate the congruence between pre-ingestive visual and cognitivecues and the actual sensory quality (taste and/or odour) once thesample has been ingested, extrapolating the exploration of the ef-fects of congruence in interactions between tastes and odours(Frank, & Byram, 1988; Labbe, Damevin, Vaccher, Morgenegg, &Martin, 2006 ). In most circumstances, visual cues will be a reliableindicator of the actual avour quality of a food, both in terms of overall recognition of the nature of the food and also whetherthe food is in an appropriate state to be ingested. However, whenthere is a lack of congruence between the expected and actual sen-sory quality of a food, this may lead to perceptual confusionand soalter the sensory experience itself.

Alongside a clear literature on the extent to which visualappearance may alter our ability to identify, and to some extentmodify the sensory quality of a food or drink, the extent to whichexpectations about avour also modify our hedonic evaluation of afood has also received attention ( Cardello, 2007; Deliza, & Mace,1996 ). Actual food choice often occurs based on written or verbaldescription of a food, even before the actual food has been seen.Thus, in restaurants our choice is based on expectations of likingfor avours implicit in descriptions of the potential foods on offer,with the expectation that the description and actual sensory qual-ity will be congruent. In relation to food avour, congruence hasbeen dened as ‘‘the extent to which two stimuli are appropriatefor combination in a food product” ( Schifferstein, & Verlegh,1996 ), and has been widely used to denote the impact of percep-tual similarity between elements in food avour on changes in sen-sory quality. For example, perceptual similarity between an odourand taste was a good predictor of taste intensity ( Frank, Shaffer, &Smith, 1991 ).

Expectations about the sensory quality of a stimulus can alter

liking and perception of that stimulus in two contrasting ways.Firstly, the sensed and expected sensory qualities may combine,so resulting in actual evaluations which are closer to the expectedevaluation than is seen when the same item is evaluated withoutprior expectation. These outcome can be explained by assimilationtheory, rst proposed in relation to attitudinal change in socialpsychology ( Hovland, Harvey, & Sherif, 1957 ), where attitudesare adjusted by prior expectation. In relation to perception of thequalities of food stimuli, many studies have reported assimilationeffects, both in relation to affective (liking) evaluations and sensoryevaluations ( Cardello, & Sawyer, 1992; Deliza, & Mace, 1996; Kah-konen, Tuorila, & Rita, 1996; Lange, Rousseau, & Issanchou, 1999;Schifferstein, Kole, & Mojet, 1999; Tuorila, Cardello, & Lesher,1994 ). For example, verbal descriptions which implied that a prod-

uct (pomegranate juice) was very pleasant (e.g. the statement thatthe product scored 8.1 on a 9 point liking scale) or very unpleasant

(e.g., that it scored 1.9 on a 9 point liking scale) generated expecta-tions in line with these ratings ( Cardello, & Sawyer, 1992 ). Accord-ingly, a positive expectation lead to a small increase in actual ratedliking on tasting the product (assimilation) although an expecta-tion of a disliked avour had minimal effects on actual liking forthe tasted product. Effects on sensory qualities were clearer: beingtold that a product had a bitter taste increased rated bitterness ontasting, while expectations of low bitterness tended to decreasebitterness evaluations. The authors concluded that the study pro-vided evidence for the assimilation model: actual and expectedsensory experience combined to generate the overall avour expe-rience and liking. In relation to evaluationof liking, recent researchconducted under semi-naturalistic conditions in a cafeteria sup-ports the idea of assimilation. Thus, the use of evocative descriptivemenu names resulted in stronger positive evaluations of the foodafter it had been consumed than when the same food had been la-belled by nutritionally accurate but non-evocative names ( Wan-sink, van Ittersum, & Painter, 2005 ). Likewise, labelling a tomatosoup with a name implying a higher quality (e.g., ‘‘Gastronome’sConnoisseur’s Choice Cream of Tomato” relative to ‘‘McTaggart’sLean and Low Tomato”) resulted in signicantly higher hedonicratings for the same soup regardless of actual nutrient content(Yeomans, Lartamo, Procter, Lee, & Gray, 2001 ), and also resultedin higher ratings of creaminess of the soup.

In the examples above, actual evaluations of foods generallychanged to be more in line with the expected quality even thoughthere was a discrepancy between the expected and actual qualitiesof these stimuli. However, as discussed earlier, although moststudies of effects of expectations on evaluations of foods result inassimilation, in some cases such discrepancies can lead to a de-crease in the rated quality (contrast effect) rather than assimilationFor example, a strong expectationthat an unusual breath freshener(Jintan) had a pleasant taste (ie was a form of ‘‘Japanese candy”) re-sulted in markedly lower liking ratings than when Jintan was as-sessed without expectation ( Zellner, Strickhouser, & Tornow,2001 ).

A key question is then what determines whether informationabout a product leads to an enhanced evaluation (assimilation)or a decrease (contrast)? Recent reviews suggest a number of fac-tors may be important ( Cardello, 2007; Schifferstein, 2001 ). Firstly,the size of the discrepancy: where the difference between actualand expected qualities are small, the difference may not be noted,and so assimilation takes place, whereas if the discrepancy is large,contrast may occur. This effect is capturedwell by the affect expec-tation model ( Wilson, Lisle, Kraft, & Wetzel, 1989 ). Where the dis-crepancy is not apparent, the expectation is no longer a point of reference and so is not directly compared with the actual qualities.In relation to food, several studies report ndings consistent withthis idea (see Cardello, 2007 for review). A second factor is thestrength of the expectation: even where there is a large discrep-

ancy between expectedand actual properties, assimilation mayoc-cur if the expectation is very strong. In relation to food, animportant test of these ideas was reported by Zellner et al.(2001) . Their participants’ evaluated two novel foods, Jintan andguanabana nectar, with expectation about liking manipulated bythe informationprovided beforehand. Assimilation occurred whereexpectation were based on specic informationabout the nature of the food (e.g., where participants assessing Jintan were told thatother assessors had rated this as very disliked), even when the ex-tent of the expected dislike was much greater than that seen whenthe food was evaluated without prior expectations, but contrastwas seen where the expectation and actual experience were verydifferent. The ndings by Zellner and colleagues are importantsince they contrast with a larger literature suggesting assimilation

is the normal response to disconrmed expectancies with food,discussed earlier. One reason for this may be that most previous

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studies have concentrated on subtle differences in quality betweenthe expected and actual properties of foods, conditions whichwould favour assimilation, whereas Zellner et al. (2001) explicitlyexplored conditions where expectations could be disconrmed.Thus in hedonic evaluations, both assimilation and contrast arepossible outcomes of prior expectations, depending on thestrength, plausibility and nature of the expectations.

The affect expectation model can be applied usefully to under-standing of expectations of liking, but since it is grounded in affect,it is less directly applicable to evaluations of sensory rather thanaffectivequality.Notably, Zellner et al. (2001) only measured hedo-nic evaluations, and the effect of large disconrmed expectancieson sensoryrather than hedonic evaluations remainsunder-studied.In one early study, participants rated sucrose or quinine solutionswhich were either labelled correctly or incorrectly ( Carlsmith, &Aronson, 1963 ). Disconrmed expectancies resulted in contrast ef-fects: quinine was rated as more bitter when labelled as sucrose,and vice versa. However, the authors interpreted these changes insweet and bitter dimensions as a reectionof hedonic changes. Re-cent work, however, suggests that sweet and bitter ratings are dis-sociable from hedonic evaluations (e.g., Yeomans, Mobini, Elliman,Walker, & Stevenson, 2006 ), which implies that the outcome of thestudy by Carlsmith and Aronson (1963) may reect actual sensoryrather than hedonic changes. Other studies report assimilation of labelled sensory quality intoactual product evaluations (e.g., Capo-rale, Policastro, Carlucci, & Monteleone, 2006 ; e.g., Cardello, & Saw-yer, 1992; Tuorilaet al., 1994 ), but in the context of foodswhichhadqualities which were similar to expectations, and so may promoteassimilation since thedifference betweenexpected andactualqual-ities may not have been noticeable. Thus there is a need for furtherstudies exploring the role of expectation in sensory and hedonicevaluations of foods where expectations are disconrmed, and thisdifference is apparent to the consumer, and that was the aimof theexperiments reported here.

The aimof the threeexperiments described in this report was toexplore the importance of congruency between the expected a-vour (generated by a combination of a simple food label and visualappearance) and actual sensory experience of a highly novel foodwhich had the capacity to generate extreme differences betweenexpectations and actual sensory qualities. To achieve this, we gen-erated a highly novel food (smoked salmon ice-cream) whose vi-sual appearance could be interpreted either as a fruit ice-creamor savoury mousse. Critically, we wanted to determine the extentto which hedonic and sensory evaluation of the food was inu-enced by the congruence between the expected and actual avour.Where the label predicted the actual sensory experience (i.e., a la-bel of ‘‘frozen savoury mousse”), we predicted that the food wouldbe perceived as acceptable. However, where the expectationgener-ated by the label predicted a sweet food (i.e. when the food was la-belled as ‘‘ice-cream”), we predicted that liking would be

signicantly reduced when the actual food was experienced. More-over the experience of unexpected sensory qualities (a savoury,salty sh avour) might lead to over-estimation of the key sensoryattributes of the salmon ice-cream due to the strong contrast be-tween expected and perceived avour.

2. Experiment 1

2.1. Method

2.1.2. DesignThe study used a between-subjects design to contrast hedonic

and sensory evaluations of a novel food (smoked-salmon ice-

cream) depending on whether this was presented to assessors as‘‘ice-cream” or ‘‘frozen savoury mousse”.

2.1.3. ParticipantsThe participants were an untrained panel of 32 assessors (24

women and 8 men) selected from staff and students at the Univer-sity of Sussex who had previously shown an interest in studiesrelating to ingestion. Potential volunteers were contacted throughemail, and were informed that the study simply involved evalua-tion of a novel ice-cream. Volunteers who had diabetes, had anyknown or suspected food allergy or had a prior diagnosis of an eat-ing disorder were excluded, and the study was described as unsuit-able for vegetarians. The participants were the rst 32 respondentswho met the study criteria. Participants were assigned at randomto either an informed ICE-CREAM or informed SAVOURY group,while ensuring the same gender ratio (there were 16 participants,12 women and 4 men, in each condition). The two groups did notdiffer signicantly in age.

2.1.4. Test foodThe food used in the test was a novel smoked-salmon ice-

cream, based on an original idea by Heston Blumenthal and thendeveloped further by Firmenich SA in Geneva. The ice-cream wasunusual in that it was not sweet; it contained the followingingredients:

565 ml: full fat UHT milk obtained from a local supermarket. 200 ml: UHT cream with a 35% fat content obtained froma local

supermarket. 235 g: maltodextrin with a dextrose equivalent of 10 (Star-Dri

10 from Tate & Lyle plc). 230 g: scottish smoked salmon obtained from a local

supermarket. 8 g: sodium chloride. 3 g: MSG (monosodium glutamate from Ajinomoto plc).

The cream, milk, maltodextrin, salt and MSG were thoroughlymixed to be free of any lumps and passed through a kitchen sieve.900 ml of this mix were placed in the stainless steel beaker from aPacojet Machine (Pacojet AG, Bundesstraße 7, CH-6300 Zug/Swit-zerland). A small aluminium bottle (5 cm diameter) was lled withtable salt and capped. This was placed in the centre of the Pacojetbeaker and was tall enough to protrude above the level of the li-quid. The whole was covered and placed in a deep freezer over-night. The next day the salt was poured out of the aluminiumbottle and replaced with warm water; this allowed the bottle tobe easily removed from the frozen mix leaving a central verticalhole from top to bottom. This hole was packed with the smokedsalmon and the whole container was stored in the deep freezer un-til needed.

The Pacojet machine is designed to forcibly grind and churn aportion of a frozen mass into a nely divided purée. In this case

it thoroughly mixes the frozen cream mix with the salmon to ahomogeneous and smooth consistency; in this process ice crys-tals are reduced to a size that is compatible with a smoothcreamy ice-cream. The overall colour was pink/peach with novisible sign of salmon pieces. For the sensory tasting sessions,a single scoop of ice-cream (c. 30 g) was served in a small plastictray.

2.1.5. ProcedureParticipants attended for a single tasting session, which was

conducted between 1445 and 1600 h in small, air-conditionedwindowless cubicles in the Ingestive Behaviour Unit at SussexUniversity, having been instructed to refrain from eating and to

drink only water for the two hours prior to testing. All data werecollected using Sussex Ingestion Pattern Monitor software (see

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Yeomans, 2000 ) run on Apple G3 computers. Initially participantscompleted a series of computerised mood and appetite ratings inthe form ‘‘How hword i do you feel?”, where the adjectives ratedwere: clear-headed, drowsy, thirsty, lively, calm, full, nervous, re-laxed, hunger and nauseous. Ratings were made by positioning abar at the point of a horizontal line 500 pixels long which best re-ected how participants currently felt, and ratings were scoredautomatically on a scale from 0 (not at all) to 500 (extremely).The polarity of the scale varied at random, as did the order inwhich ratings were made, and the adjective describing the dimen-sion to be rated was positioned centrally above the rating scale.The appetite and key mood ratings (anxious, nauseous and ner-vous) were used to test for spurious group differences which mighthave confounded any differences in hedonic evaluations of the ice-cream, and the remaining mood evaluations were included both toensure familiarity with the computerised ratings, and to disguisethe purpose of the study. After completion of the nal mood rating,the computer signalled the participant to call the experimenter,who immediately served the ice-cream portion, along with freshmineral water for participants to use to cleanse their mouth aftertasting. The key manipulation in the study was the description of the ice-cream on-screen at the time of evaluation. In the ICE-CREAM condition, the food was labelled as ‘‘ice-cream”, but inthe SAVOURY condition the description given to participants was‘‘frozen savoury mousse”. Evaluations of the ice-cream were allmade using the same style of ratings as with the mood and appe-tite scales. Participants made one hedonic rating (‘‘How pleasantis the taste?”), a rating of avour strength (strong) and sevenavour descriptors (fruity, savoury, sour, creamy, salty, bitter andsweet). As with the mood/appetite ratings, the order in whichevaluations were made was randomised. Once these ratings hadbeen completed, the participant was debriefed, and rewardedeither with a small payment or course credits for researchparticipation.

2.1.6. Data analysisInitial analyses were aimed at conrming that the between-

groups contrast of hedonic evaluation of the ice-cream was notinvalidated by spurious differences in appetite and mood at thetime of testing. Thus each mood and appetite rating was contrastedbetween the ‘‘ice-cream” and ‘‘savoury mousse” conditions usingANOVA, with gender of assessor as a controlled factor. The sameanalysis was then used to assess the rated characteristics of theice-cream between the two groups.

2.2. Results

Assessors who were pre-informed that the food was a frozensavoury mousse (condition SAVOURY) rated the avour of thesmoked salmon ice-cream as signicantly more pleasant thandid those who experienced the same food simply labelled asice-cream ( F (1,28) = 11.34, p < 0.005), with the latter conditionnding the avour extremely aversive, compared to a mild dis-like in the savoury condition ( Fig. 1 a). Thus expectancy generatedby the physical appearance of the food combined with a simplewritten descriptor had a large effect on rated avour pleasant-ness. In addition, ratings of saltiness were signicantly greaterin the ICE-CREAM than SAVOURY condition ( F (1,28) = 5.96, p < 0.05: Fig. 1 b), and the ICE-CREAM condition also perceivedthe avour as stronger overall ( F (1, 28) = 7.63, p < 0.01: Fig. 1 c).Ratings of bitterness were variable, but again assessors in theICE-CREAM condition tended to rate the avour as more bitterthan did those in the SAVOURY condition ( F (1, 28) = 3.32, p = 0.079: Fig. 1 d). None of the other sensory ratings differed be-tween conditions.

Evaluation of baseline ratings ( Table 1 ) conrmed no spuriousdifferences in appetite (hunger, fullness or thirst) or mood (anxi-ety, nervous and nausea) that could account for differences in eval-uation of ice-cream avour, and no analysis found any differences

Fig. 1. Rated pleasantness (A), saltiness (B), strength of avour (C) and bitterness (D) of smokedsalmon ice-cream depending on whether this was labelled as frozen savourymousse or ice-cream. Data are mean ± SEM.

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between female and male assessors either in baseline mood andappetite or in assessment of the ice-cream.

2.3. Conclusion

These data suggest that the sensory qualities implied by a sim-ple food label affected the perceived pleasantness of avour of anovel, and also modied actual perception of avour components.More importantly, these data imply that inaccurate expectationsabout food avour can lead to strongly aversive responses whenthe food was tasted, in line with a limited existing literature alsoshowing hedonic contrast effects with food stimuli ( Cardello, &

Sawyer, 1992; Zellner et al., 2001 ). These data thus consistent withthe idea that avour perception is an integration of sensory infor-mation with past memory of similar stimuli predicted by the visualqualities, and accompanying written descriptor, of the rated food.However, two methodological issues limit interpretation of Exper-iment 1. Firstly, the recruitment strategy identied the study as an‘‘ice-cream” tasting study during the recruitment of participants.Consequently, the specic information that the product was a ‘‘fro-zen savoury mousse” may have had less impact than if participantshad not had the initial expectation of ice-cream. Secondly, whileExperiment 1 established large differences in evaluation of thesmoked salmon ice-cream depending on the associated label, it isimpossible to determine whether this resulted from the negativeimpact of incongruous ice-cream label, or a positive effect of con-

gruous frozen savoury mousse label. Experiment 2 was designedto counter these limitations.

3. Experiment 2

3.1. Method

3.1.1. DesignA between-subjects design was again used to contrast hedonic

and sensory evaluations of a novel food (smoked salmon ice-cream) with the same two conditions (‘‘ice-cream” or ‘‘frozensavoury mousse”) as in Experiment 1, and a third control conditionwhich provided no descriptive information (‘‘Food 386”).

3.1.2. ParticipantsThe participants were 44 untrained assessors. The recruitmentwas the same as in Experiment 1 except that the description of the study in all communications prior to testing, and in the infor-mation sheet for participants, described the study as ‘‘assessing anovel food”. Participants were assigned at random to the three con-ditions, with the original aim of using 15 participants in each con-

dition. However, one participant failed to attend their test session,and the nal composition of the three panels ( Table 2 ) had 15 par-ticipants in the SAVOURY and CONTROL conditions, but 14 in theICE-CREAM condition.

3.1.3. Procedure and test foodThe same test food was used as in Experiment 1, and the proce-

dure was identical with the sole exception that the on-screendescriptor of the food to be assessed in the CONTROL conditionwas ‘‘Food 386”.

3.1.4. Data analysisEach rating was contrasted between the three conditions using

one-way ANOVA, with gender of assessor as a controlled factor.Where signicant effects of condition were found, post-hoc con-trasts were used to conrm which differences between the threeconditions were signicant, with signicance adjusted for multi-ple-contrasts using the Bonferroni adjustment.

3.2. Results

Analysis of pleasantness ratings found an overall effect of con-dition [ F (2, 41) = 5.04, p < 0.05]. Inspection of the pleasantnessdata, however, revealed that one participant was a signicant out-lier (data more than 2SD from the group mean) in the ICE-CREAMcondition. This participant gave a pleasantness rating of 475 to thesmoked salmon ice-cream labelled as ice-cream, compared to agroup mean of 40.1 ± 36.4. Notably, this participant, who wasSpanish, commented that he had experience of savoury ice-cream,which he liked. Exclusion of these data increased the signicanceof the effect of condition on pleasantness [ F (2, 40) = 9.68, p < 0.001]. Protected contrasts revealed that ratings in the ice-cream condition were signicantly less than in the other two con-ditions, but ratings in the control and savoury condition did notdiffer signicantly ( Fig. 2 a).

The effects of labelling on sensory evaluation seen in Experi-ment 1 were partly replicated. Saltiness also varied with condition[F (2, 40) = 5.08, p < 0.05], and as in Experiment 1 rated saltinesswas higher in the ice-cream than savoury condition ( Fig. 2 b), butsavoury and control conditions did not differ signicantly. As inExperiment 1, perceived avour strength varied with condition[F (2, 40) = 5.69, p < 0.001], with higher ratings in the ICE-CREAMthan savoury or control conditions ( Fig. 2 c). There was also a trendfor higher savoury ratings in the ice-cream condition, but this didnot reach overall signicance [ F (2,40) = 1.94, NS]. Although themean ratings for bitterness in Experiment 2 were in the samedirection as Experiment, with higher bitterness ratings in the ice-cream than savoury condition, the overall effect of condition wasnot signicant [ F (2, 40) = 0.88, NS].

No signicant effects of condition were found on creaminess,fruitiness, sourness or sweetness evaluations, although in manyratings there were trends for ratings in the ice-cream conditionstanding out as different to the other conditions (tending to bemore sour, less sweet, etc.).

3.3. Conclusion

Experiment 2 suggests that it was the lack of congruity betweenthe label ‘‘ice-cream” and the experienced sensory quality of thesmoked salmon ice-cream that resulted in the strong aversive re-sponse in the ICE-CREAM condition in both Experiment 1 and 2since reactions in the conditions where the label was informativeand accurate (‘‘frozen savoury mousse”) and uninformative (CON-

TROL condition labelled ‘‘Food 386”) were very similar. The differ-ences in hedonic evaluation between the ICE-CREAM and

Table 1

Baseline ratings of appetite and mood prior to avour evaluation in Experiment 1

Attr ibute rated ICE-CREAM condition SAVOURY condition

Full 239.1 ± 18.9 231.7 ± 27.1Hunger 192.4 ± 25.9 203.5 ± 30.7Thirst 242.5 ± 26.9 234.3 ± 26.5Nauseous 65.7 ± 27.6 65.5 ± 24.5Nervous 157.2. ± 28.3 152.9 ± 29.4

Table 2

Characteristics of the participants in Experiment 2

Condition

Control Ice-cream Savoury

Age 21.3 ± 1.0 21.4 ± 0.7 21.1 ± 0.5BMI 22.7 ± 0.6 22.1 ± 0.6 22.6 ± 0.5Gender (F/M) 12/3 11/3 11/4

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SAVOURY conditions in Experiments 1 and 2 were very similar,with the food rated as having a stronger and more salty avourin the ice-cream label condition, although the hedonic differenceswere much greater than sensory differences.

The similarity in assessment of the salmon ice-cream in theSAVOURY and CONTROL conditions was surprising since theappearance of the food might have been predicted to generateexpectations of a sweet ice-cream. However, a shortcoming inExperiments 1 and 2 was that differences in expectation betweenconditions were implied but not tested explicitly. Previous re-search has assessed the role of expectation by obtaining separateratings based on appearance alone prior to sensory testing (e.g.,Cardello, & Sawyer, 1992 ). The same approach was discounted herebecause of concerns that the inspection of the food during the eval-uation of the appearance may have led to participants detectingthe faint odour of sh from the ice-cream, so compromising the la-

bel manipulation. However, to test whether the manipulationsused in the present study did generate the inferred expectations,a nal study examined contrasted the effects of the label manipu-lations on evaluations of both the expected and actual sensory andhedonic evaluations of the ice-cream in the three conditions usedin Experiment 2.

4. Experiment 3

4.1. Method

4.1.1. DesignA between-subjects design was used to contrast anticipatory

and actual hedonic and sensory evaluations of the same novel food

(smoked salmon ice-cream) in the three label conditions used inExperiment 2 (ICE-CREAM, SAVOURY and CONTROL).

4.1.2. ParticipantsThe participants were 60 untrained assessors, 48 women and 12

men. The recruitment was the same as that in Experiment 2, andparticipants were assigned at randomto the three conditions, with20 participants in each condition.

4.1.3. Procedure and test foodThe same test food was used as in Experiments 1 and 2. How-

ever, in this case when the food was rst presented, participantsrstly made the same set of evaluations as in the previous studiesbut based purely on the appearance of the food. The food was

placed towards the back of the test table and participants were in-structed to base their evaluations on the appearance alone during

this phase. After completion of the nal rating of expected avour,an additional rating was made based on howcondent participantswere about their evaluation of the food by label and appearance.The question was phrased ‘‘How condent are you that you haveaccurately described the avour of this food?”, rated form not atall (0) to totally (500). Once completed, the food was placed infront of the participants to allow them to consume a small portionand make a second set of evaluations, using the same procedure asin Experiments 1 and 2.

4.1.4. Data analysisThe expected and actual evaluations of the ice-creamwere con-

trasted using ANOVA, with label between-subjects factor and typeof evaluation(expected or actual) within-subjects. Gender of asses-sor was again included as a controlled factor. Where signicant ef-fects of condition were found, post-hoc contrasts were used to

conrm which differences between the three conditions were sig-nicant, with signicance adjusted for multiple-contrasts using theBonferroni adjustment.

5. Results

5.1. Expected avour evaluations

Average sensory and hedonic evaluations of the expected a-vour of the salmon ice-cream in the three conditions are summa-rised in Table 3 . These data conrm that the label applied to the

Fig. 2. Rated pleasantness (A), saltiness (B) and strength of avour (C) of smoked salmon ice-cream depending on whether this was labelled as ice-cream, frozen savourymousse or a neutral food (Control). Data are mean ± SEM.

Table 3

Expected sensory and hedonic evaluations of the salmon ice-cream in the three label

conditions in Experiment 3

Evaluation Label condition Main effect of condition 1

Ice-cream Savourymousse

Food 386

Pleasant 375 a ± 13 241 b ± 23 258 b ± 18 p < 0.001Savoury 50 a ± 8 482 c ± 5 121 b ± 19 p < 0.001Salty 31 a ± 6 323 b ± 30 69 a ± 17 p < 0.001Sweet 340 a ± 28 89 c ± 13 275 b ± 19 p < 0.001Creamy 389 a ± 13 314 b ± 18 320 b ± 16 p < 0.01Fruity 322 a ± 15 76 c ± 13 225 b ± 26 p < 0.001Bitter 87 ± 17 104 ± 17 118 ± 20 NSSour 56 ± 13 62 ± 11 47 ± 9 NSStrong 256 a ± 15 387 b ± 11 300 a ± 20 p < 0.001Condence 329 a ± 17 284 a ± 19 146 b ± 25 p < 0.001

Data are mean ± SEM, n = 20 in each group1 Value is signicance for main effect of condition from one-way ANOVA. Means

with different superscripts differ signicantly (bonferroni contrast).

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ings of avour strength and saltiness for the food when labelled as‘‘ice-cream”.The implication is that the ‘‘ice-cream” label generateda strong expectationof a sweet, fruity avour, and the surprise of astrong, salty sh-avoured food resulted in very low pleasantnessratings (many participants verbally described the food as disgust-ing). Experiment 3 explicitly measured expected and actual evalu-ations, and conrmed the interpretation of Experiments 1 and 2that the ‘‘ice-cream” label did generate an expectation of a sweet,fruity avour, which then contrasted strongly with the actualexperience of salty sh.

Although past research has shown that expectations generatedby food labels can modify liking for food avours, the majority of these studies have found assimilation of the expected and actualexperience ( Cardello, Maller, Masor, Dubose, & Edelman, 1985;Cardello, & Sawyer, 1992; Wansink et al., 2005 ). However the pres-ent study demonstrates that where the expected and actual sen-sory experience are very different (i.e., the contrast of anexpectation for sweet and fruity relative to actual salty sh), thedisconrmed expectation leads to a strong contrast effect, and con-sequent dislike and rejection of the test food, adding to the veryfew studies reporting contrast effects with food stimuli (e.g., Car-dello, & Sawyer, 1992; Zellner et al., 2001 ). Thus where the differ-ence between expectation and actual sensory quality was verylarge, the experience was highly unpleasant even for a food thatcould be perceived as pleasant on its own (the pleasantness ratingsfor the salmon ice-cream in the conditions other than ‘‘ice-cream”were close to neutral, 250 on the hedonic scale used here). Thuswhere expectations were disconrmed and the actual sensoryexperience was highly novel and surprising, the reaction was oneof extreme dislike. Although these conditions would rarely beexperienced by a consumer in real-life, the extent to which expec-tations inuenced liking in the present context demonstrate thepotential for expectations to moderate hedonic evaluation wherethere is a clear mis-match between expected and perceived sen-sory quality. It was also notable that positive expectations aboutthe novel food generated by the label ‘‘frozen savoury mousse”did not lead to assimilation of the expected avour since no differ-ences emerged between the congruent and neutral food label con-ditions in Experiment 3. A possible explanation for this might bethat the expectations generated by the congruent label were notsufciently strong to facilitate assimilation when the actual foodwas tasted, perhaps driven by the unique novelty of the foodtested. This conclusion is supported in part by the nding that con-dence ratings in the SAVOURY condition were less than in ICE-CREAM, but notably both were greater than in the CONTROL con-dition. However, the large difference in condence in ratings be-tween SAVOURY and CONTROL conditions might have beenexpected to promote assimilation in the SAVOURY condition. An-other possible explanation for the lack of assimilation in theSAVOURY condition was that the description of the study as eval-

uation of a novel food generated an expectation of novelty, whichalerted reduced the surprise when salmon ice-cream was tasted inthe CONTROL condition without giving any condence of whatsensory quality they would experience. This possibility could beassessed in future studies.

The present data also conrm and extend previous ndings onthe role of expectation on sensory evaluation, particularly in rela-tion to evidence for a contrast effect when expectations about sen-sory quality were disconrmed, a phenomena which has beenrarely reported for the effects of expectations generated by infor-mation prior to tasting for food stimuli, where assimilation is againthe normal response to disconrmed expectations. Thus where asweet fruity avour was expected but a salty sh avour experi-enced (the ICE-CREAM condition), the unexpected qualities tended

to be rated as stronger sensory experiences than in conditionswhere either the expectation was for a similar product (the

SAVOURY condition), or where information gave no expectation(the uninformative CONTROL food label). These data are important,as they provide a rare example of contrast effects in sensory eval-uation generated by expectations about avour in a food context.Although interpreted at the time as evidence of hedonic change,data in the study by Carlsmith and Aronson (1963) also show con-trast effects, with sweet solutions rated as less sweet when bitter-ness was predicted and vice versa. Contrast effects are more readilyseen in perceptual studies where evaluation of a context stimulusof higher or lower intensity alters evaluation of subsequent targetstimuli (e.g., Conner, Land, & Booth, 1987; Riskey, Parducci, & Beau-champ, 1979 ; see Schifferstein, 2001 for review), but no such con-text stimuli preceded evaluation of the test stimulus in the presentstudy, suggesting that adaptation or range-frequency effects ( Par-ducci, 1965 ) cannot explain the current ndings of exaggeratedsensory experience. Thus the present data suggest that disconr-mation about sensory expectation can lead to increased intensityof the unexpected sensory quality, suggesting some top-down con-trol inuence on sensory experience in this context.

The current studies also suggest that beliefs about the nature ofafood generated by the preceding food label were more powerfulthan were the visual cues alone. Thus the differences in sensoryand hedonic evaluation of the salmon ice-cream between the threetest conditions all involved the same visual cues, yet responses tovisual cues alone (the CONTROL condition where the food labelwas uninformative in Experiments 2 and 3) and visual cues withan accurate food label (the SAVOURY condition) were the same.Only where the food label was congruent with the visual cues butmisleading about the actual sensory quality (the ICE-CREAMcondi-tion) did differences in sensory and hedonic evaluation emerge.

A limitation of the rst two experiments in the current studywas that no actual evaluation of the expected pleasantness or a-vour quality of the food was made before the food was consumed.Although explicit data regarding anticipated avour would havesome value here, we were concerned that asking participants toevaluate their expectations prior to tasting may have led to themdetect the aroma of sh, and so compromised the lack of congruitybetween the label and sensory qualities. Experiment 3, however,did measure expected and actual ratings and the similarity in sen-sory evaluations for the actual avour of the ice-cream in Experi-ments 2 and 3 suggest that completion of expected ratings didnot impact adversely on subsequent hedonic and sensory evalua-tions. The inclusion of expected and actual ratings in Experiment3 did demonstrate the extent of the difference between expectedand actual pleasantness.

In summary, these three experiments provide striking evidencethat expectations play a major role in generating hedonic re-sponses to food stimuli, such that the same food was rated asacceptable when the avour was expected but close to disgustingwhen the expected and actual avour were very different. These

data thus add to a small set of studies showing hedonic and sen-sory contrast effects in avour perception.

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