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Research report
Is the desire to eat familiar and unfamiliar meat products influenced by
the emotions expressed on eaters’ faces?
S. Rousseta,!, P. Schlichb, A. Chatonniera, L. Barthomeufc, S. Droit-Voletc
a
Institut National de la Recherche Agronomique, UMR 1019, Centre de Recherche en Nutrition Humaine d’Auvergne, 58 rue Montalembert,
63009 Clermont-Ferrand, France
b
Centre Européen des Sciences du Goût, 15 rue Hugues Picardet, 21000 Dijon, France
c
Laboratoire de Psychologie Sociale et Cognitive, UMR 6024 CNRS, 34 Avenue Carnot, 63000 Clermont-Ferrand, France
Received 12 October 2006; received in revised form 1 June 2007; accepted 1 June 2007
Abstract
The aim of the present study was to test if the social context represented by eaters’ faces expressing emotions can modulate the desire to
eat meat, especially for unfamiliar meat products. Forty-four young men and women were presented with two series of photographs. The
first series (non-social context) was composed of eight meat pictures, four unfamiliar and four familiar. The second series (social context)
consisted of the same pictures presented with eaters expressing three different emotions: disgust, pleasure or neutrality. For every picture,
the participants were asked to estimate the intensity of their desire to eat the meat product viewed on the picture. Results showed that
meat desire depended on interactions between product familiarity, social context and the participant’s gender. In the non-social context,
the men liked the familiar meat products more than the women, whereas their desire to eat unfamiliar meat products was similar.
Compared to the non-social context, viewing another person eating with a neutral and a happy facial expression increased the desire to
eat. Furthermore, the increase in the desire to eat meat associated with happy faces was greater for the unfamiliar than for the familiar
meat products in men, and greater for the familiar than for the unfamiliar meats in women. In the presence of disgusted faces, the desire
to eat meat remained constant for unfamiliar products in all participants whereas it only decreased for familiar products in men.
r 2007 Elsevier Ltd. All rights reserved.
Keywords: Eating; Emotion; Meat; Faces; Familiarity
Introduction
The sensory aspects of foods elicit emotional reactions of
pleasure or disgust that are often considered as major
reasons for the choice and the preference of foods
(Eertmans, Baeyens, & Van den Bergh, 2001; Meiselman
& Rivlin, 1986; Rozin, 1990). Dislike of a food thus leads
to its rejection. However, according to Rozin and Fallon
(1980), three psychologically meaningful categories explain
food rejection: distaste, danger and disgust. Distaste is
produced by the dislike of the appearance, taste or smell
and/or texture of food. Danger is associated with the
harmful consequences of ingestion. Disgust is generated on
!Corresponding author.
E-mail addresses: rousset@clermont.inra.fr (S. Rousset),
droit-volet@univ-bpclermont.fr (S. Droit-Volet).
0195-6663/$ - see front matter r 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.appet.2007.06.005
both ideational grounds and the distaste produced by
contamination or by the intake of inedible foodstuffs.
Food avoidance, a related but different topic concerns
the process of rejection of unfamiliar food. This is related
to neophobia, the reluctance to try unfamiliar foods, and
the willingness to taste familiar rather than unfamiliar
foods (Pliner & Hobden, 1992; Pliner, Latheenmaki, &
Tuorila, 1998). Among the causes of neophobia are the fear
of experiencing a bad taste and/or of being poisoned, as
well as the fear of new experiences, more closely related to
personality traits. Regardless of the case, reactions to
unfamiliar animal foods, particularly meats, would also be
mediated by the strong basic emotion of disgust (Pliner &
Pelchat, 1991). To decrease neophobia, the authors
proposed either to force exposure to an unfamiliar food
in order to confirm or not the expectation of unpalatability
(Pliner, 1982; Pliner & Hobden, 1992; Zajonc, 1968;
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Zajonc, Markus, & Wilson, 1974), to associate this food
with pleasant or familiar tastes by conditioning, or to
provide information about these foods (Martins, Pelchat,
& Pliner, 1997). To date, however, the possibility of
decreasing or increasing neophobia in the social context by
the presence of another person or other people expressing
different emotions towards the unfamiliar food products
has been rarely empirically studied.
Since Lewin (1958), study in the power of the social
context has been demonstrated on the change in eating
habits, notably concerning disliked foods such as beef
heart, sweetbread and kidneys. This author tested the
influence of two types of intervention (individual and
group) on housewives. In the individual case, only 3% of
the women as opposed to 32% in the group case actually
tried these meats. Although several factors explained these
results, Lewin emphasized the influence of the social group
and the difficulties of individuals to differentiate themselves
too much from the group. As he said, the individual is
likely to change only if the group changes (Lewin &
Grabbe, 1945).
The effect of social influence in the domain of eating is
now well known (for a review see Herman, Roth, and
Polivy (2003)). Notably, modelling studies suggested that
the presence of others may facilitate or inhibit intake,
depending on how much the model(s) eat(s). For example,
Rosenthal and McSweeney (1979) showed that when a
model ate either 40 or 10 crackers, participants ate more
when paired with a high-consumption confederate than
when paired with a low consumption confederate. The
presence of others influences not only the amount of food
eaten, but also the choice of the consumed food, as
shown by Birch (1980). In her experiment, a ‘target’
child preferred vegetables A to B, while all of the other
children at the same table preferred vegetables B. During
four successive meals, the two vegetables were offered.
When the target child serves himself first, he generally
chooses vegetable A (in 80% of the cases). On the
other hand, when he serves himself last, he tends to imitate
the others and chooses vegetable B in 67% of the cases.
Birch did not draw any conclusions from the respective
effects of simple exposure to the vegetables, the emotional
context of the meal or the mimicking of behaviour. As
regards the impact of modelling on willingness to eat novel
foods, Harper and Sanders (1975) showed that more
children were willing to taste a novel food if the adult
model tasted it first than if it was only offered. Moreover,
when adult participants were exposed to eater models who
ostensibly chose novel foods among familiar and unfamiliar foods, participants were more often inclined to choose
novel foods than when they viewed models choose familiar
foods (Hobden & Pliner, 1995). In their works, Birch
(1980), and Harper and Sanders (1975) did not control the
influence of emotions expressed by the children’s or adults’
faces on the target child’s willingness to taste the vegetables
or the novel food. Conversely, Hobden and Pliner (1995)
obtained their results while showing models who expressed
neutral faces during the choice and tasting of food
products.
In non-specific nutrition-related domains of research, it
is well known that the perception of emotions expressed by
faces plays an important role on our own emotions
(Adolphs, Damasio, Tranel, Cooper, & Damasio, 2000;
Decety & Chaminade, 2003; Gallese, 2003). Indeed,
‘emotional contagion’ results from conscious appraisal,
but also from more automatic mechanisms inaccessible to
awareness, such as the automatic imitation of facial
expressions in others (Hatfield, Cacioppo, & Rapson,
1994). The recent embodiment theories of cognition hold
that the encoding of incoming emotional information
involves an internal simulation of the perceived entities
(e.g., imitation of the facial expression) with all of its
physiological implications such as matching of emotional
state (see Barsalou, Nidenthal, Barbey, & Ruppert, 2003;
Niedenthal, Barsalou, Winkielman, Krauth-Gruber, & Ric,
2005, for a review). For example, in an fMRI study,
Phillips et al. (1998) showed that the perception of facial
expression of disgust produced activation of the anterior
insula, directly involved in the physiological reaction of
disgust. In the same way, Adolphs, Tranel, and Damasio
(2003) reported on patients with damage affecting the
insula who clearly showed selective impairment in recognising facial expressions of disgust and in their sensitivity
to disgust. Since the discovery of the mirror-neuron system
(Gallese, 2005), there is now evidence that observing or just
imagining a person in a particular emotional state
automatically arouses this state with all of the somatic
and associated sensory-motor responses (Craig, 2002;
Rizzolati, Fadiga, Fogassi, & Gallese, 2002; Singer et al.
2004).
In short, the different studies described above suggest the
important power of social context on the amount of food
eaten and on the evaluation of liking or disliking food
products, especially in the case of rejection of unfamiliar
food and, more particularly, unfamiliar meat. The aim of
the present study was thus to investigate the possibility of
changing the participants’ desire to eat a food product by
the presence of other people expressing and arousing
different specified emotions. More precisely, we tested how
emotional facial expressions (pleasure, neutrality and
disgust) affect the participants’ desire to eat four familiar
and four unfamiliar meat products. We expected that
eaters’ faces expressing pleasure would increase the desire
to eat meat, compared to those expressing neutrality and
disgust, and inversely for the faces expressing disgust.
Considering the rejection of novel food, we hypothesized
that the participants should have less desire to eat
unfamiliar than familiar products. Furthermore it might
be possible that the change in desire to eat would be greater
for unfamiliar than for familiar meat products because
participants did not have any previous sensory experience
with these new foods that would influence the importance
of emotional context in the changes in neophobia. Finally
due to an in-group advantage (Durrett & Levin, 2005), i.e.,
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the tendency to imitate more members of our own group,
we also assumed that the gender of the eaters might
influence the responses of the participants.
Method
Participants
In December 2004, a convenience sample was recruited
in Clermont-Ferrand (France) through advertising in the
local newspapers, TV and displays in stores (supermarkets). Among the subjects who phoned, 95% agreed to
participate in the experiment. Eighty-eight young people,
44 men and 44 women, were recruited outside of our
laboratory, with a mean age of 24.5 (SD 2.9). The mean
body mass index (BMI) for men and women was 22.5 (SD
2.9) and 20.1 (SD 2.4), respectively. Participants were not
receiving medical treatment for any progressive illness.
They received a payment of h20 as compensation.
Materials and their validation
Pictures
The stimulus set consisted of eight pictures of meat
products and 18 of the emotional facial expressions of
models (three men and three women expressing pleasure,
neutrality and disgust). All the pictures were taken with a
digital camera (Canon Power Shot G3, 4.0 Mega pixels,
objective lens 7.2–28.8 mm 1:2.0–3.0) with a high-angle
shot in order to show large objects in detail. These
photographs were selected from a larger set of photographs
on the basis of two pre-tests, one for the meat products and
the other for the emotional expressions of the models. For
each pre-test, additional participants were recruited as
explained below.
Pre-test of pictures of meat products
Two categories of meat products were tested: unfamiliar
versus familiar meat products. Four unfamiliar beef
products were prepared by a technical centre (Association
de Développement de l’Institut de la Viande): ‘dry ham’,
3
‘cooked sausage with vegetables’, ‘cooked sausage with 5%
fat’, and another ‘cooked sausage with 15% fat’. Four
familiar pork products were purchased in a supermarket.
They were bacon, dry sausage, cooked sausage and
pistachio galantine. These food products were displayed
on a simple white plate placed on a table covered with a
beige tablecloth (Fig. 1). These eight photographs had been
previously assessed by 24 participants with a mean age of
26 (SD ¼ 4, 13 women and 11 men). Each participant rated
each photograph on perceived familiarity and classified
meat products into one of the three meat types (fresh meat,
processed pork and offal). Familiarity was assessed on a
seven-point scale (from 0, ‘‘not familiar at all’’, to 6,
‘‘extremely familiar’’). The ANOVA (effect of products
nested according to the category: unfamiliar vs. familiar
products on the ratings of familiarity) shows that the
familiarity scores of the four familiar meat products were
higher than those of unfamiliar meat products: 4.3 vs. 2.1,
p ¼ 0.03. Moreover, the familiar and unfamiliar meat
products were classified by 93% and 75% of participants as
processed meat, respectively.
Pre-test of pictures of facial expressions
Ten models, five men (mean age: 24) and five women
(mean age: 25) with a standard body mass index between
19 and 25 were recruited for the photographs. Sixty
photographs of these ten subjects showing three different
emotional expressions—neutrality, disgust and pleasure—
were taken twice under standard conditions (Fig. 2). These
photographs were then evaluated by 21 additional participants (ten men and 11 women, mean age: 25 (SD ¼ 3).
Photographs were presented in random order to the
participants. They rated each face on the basis of nine
emotional expressions: anger, disgust, fear, sadness, guilt,
surprise, interest, satisfaction and pleasure (Ekman,
Levenson, & Friesen, 1983). The term ‘without emotion’
was also added to the nine emotional expressions to
illustrate neutrality. For each emotion, the participants
responded on a seven-point scale (0, ‘‘the face does not
express this emotion’’, to 6, ‘‘the face strongly expresses
this emotion’’).
Fig. 1. Examples of familiar and unfamiliar meat products.
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Fig. 2. Examples of faces expressing pleasure, neutrality and disgust used for the validation of expression.
3
M2D1W2D1
M4D1M2D2
W5D1
M4D2
M3D1W3D2
W2D2
M3D2W3D1
W4D2
W1D2M1D2
W1D1
M1D1
2
DIM2 28.76 %
1
disgust
W5D2
W4D1
M5D1
0
-1
W4P2
W3P1
W1P1 W2P2
M3P1
M3P2
W5P1M1P1W2P1
M5P1M4P1
M2P1W3P2M1P2
pleasure M2P2M4P2
W4P1
anger
surprise
fear
guilty
sad
W1P2 satisfaction
M5P2
interest
W5P2
M5D2
M3N1
W1N2
-2
M2N2
M2N1
W5N2 W4N2
M3N2 W3N1
M4N2
M1N2
neutrality
M1N1 W4N1
W3N2 M4N1
W5N1 W1N1
W2N2
W2N1
M5N1
M5N2
-3
-4
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
DIM1 65.10%
Covariance Biplot-PCs and Loadings*4
Fig. 3. Location of the ten preliminary eater models with the three facial expressions in the emotional space (principal plot of PCA). The first two
characters indicate the gender (M: man and W: for woman) and the model code (no. 1, 2, 3, 4 or 5). The third character, D, N and P, indicates that the
model expresses disgust, neutrality or pleasure. The last number shows the photograph replicate.
A principal component analysis (PCA) computed on the
covariance matrix was carried out with the mean intensities
of emotional words for each photograph. The first two axes
of the PCA accounted for 94% of total inertia, i.e., the
information generated by all of the data (Fig. 3). The right
part of the first horizontal axis was explained by ‘‘satisfaction’’, ‘‘pleasure’’ and ‘‘interest’’, which were opposed to
‘‘fear’’, ‘‘sadness’’ and ‘‘guilt’’ (the left part of the first
axis). The second vertical axis opposed ‘‘disgust’’ and
‘‘anger’’ at the top, to ‘‘neutrality’’ at the bottom.
‘‘Surprise’’ was poorly represented on the plot. In that
emotional space, three distinct groups of faces appeared.
The faces expressing pleasure were located on the right,
those expressing neutrality at the bottom, and those
showing disgust in the top left corner. This result clearly
showed that the participants easily identified the three
types of emotions mimicked by the models. Certain
emotional face pictures (W1P2, M5P2, W5P2, W1N2,
M5D2, M3N1, W5D2, W4D1, M5D1, W1D1 and M1D1)
located between the groups were less clearly identified. The
results of the analyses of variance (eater’s face nested
according to gender) for each emotion confirmed that there
were significant differences in pleasure and disgust scores
given to the 20 faces expressing pleasure and disgust, F(18,
400) ¼ 5.1, po0.0001 and F(18, 400) ¼ 20.4, po0.0001 for
pleasure and disgust, respectively. However, there was little
difference in the 20 neutral scores distinguishing neutral
faces, F(18, 400) ¼ 1.5, p ¼ 0.09. The gender of the
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photographed eater did not have a significant effect on the
evaluation of disgust, F(1, 18) ¼ 0.02, p ¼ 0.89, pleasure
F(1, 18) ¼ 0.97, p ¼ 0.34 or neutral expression, F(1,
18) ¼ 0.13, p ¼ 0.72.
Table 1 shows the scores of the faces that best expressed
disgust, neutrality and pleasure, and that did not differ
between themselves in each emotional category. We therefore eliminated M5 because of its lower score of expressiveness of disgust (2.1), W4 because its disgust score was
slightly lower than those of the other subjects (4.3), and M3
and W5 because their pleasure scores (3.9 and 4.5) were
lower than those of the others.
After the six eaters were selected on the basis of their
validated emotional expressions (Fig. 2), photographs of
their body seated at a table in front of a plate containing
one of the eight meat contents were taken and subsequently
attached to their heads using Photoshop (Fig. 4).
Table 1
Intensity of emotions perceived from the six eaters that best expressed
disgust, neutrality and pleasure
Emotional expressions
Pleasure
Neutrality
Disgust
Mean
SD
Mean
SD
Mean
SD
Selected eater
Mena
M1
M2
M4
5.1
4.1
4.3
1.6
1.7
1.6
3.7
3.0
3.6
1.7
1.9
2.0
4.7
5.4
5.2
1.1
1.0
1.0
Womena
W1
W2
W3
4.9
5.3
5.3
1.5
1.3
1.0
3.8
3.8
3.7
2.1
2.2
2.1
5.1
5.3
4.9
1.4
0.8
1.1
a
The first two characters indicate the sex (M for men and W for women)
and the code (no. 1, 2, 3 or 4) of the selected eater.
5
Procedure
Subjects other than those used in the pre-tests participated in one session at the laboratory, each between 11:00
am and 2:00 pm or between 6:00 pm and 8:00 pm. They
were only instructed that they had to watch meat pictures
and to assess their desire to eat the products shown on the
picture. Each participant was presented with two series of
pictures on a computer, the order of the series being
counterbalanced across subjects. The first series was
composed of the eight meat products (four familiar and
four unfamiliar). The second series included 48 pictures,
i.e., two eaters (one man and one women chosen from
among the six selected eaters and not always the same,
depending on the participants) for the three emotional
expressions (disgust, neutrality and pleasure), and this for
the eight meat products. Within each series, pictures were
presented in random order. For each picture, the participants assessed the intensity of their eating desire on a
vertical and non-structured scale (from the bottom, ‘‘I have
no desire to eat’’, to the top ‘‘I have a great desire to eat’’).
Scores varied between 0 and 10. Both the pictures and the
eating desire scale were presented on the same screen. After
the participant scored his/her evaluation, the next screen
appeared.
Statistical analyses
We used three models of analysis of variance (repeated
measurements GLM procedure of SAS), considering the
successive evaluations of meat pictures by a given subject
as repeated measurements. The first one was performed on
the data of the first series of pictures (meat products in a
non-social context). It was a 2*2 ANOVA run on the
eating desire scale value (from 0 to 10) with participant’s
gender as a between-subject factor, familiarity (familiar vs.
unfamiliar) as a within-subject factor, and with their
interaction. The four different meat products were
Fig. 4. Examples of a male model with expressions of pleasure, neutrality and disgust towards bacon.
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considered as replicates within each familiarity level. The
following three analyses (2*2*2 ANOVAs) were carried out
on the data with the same two factors (participant’s gender,
familiarity), and an additional within-subject factor, i.e.,
the two-picture series: meat presented in the non-social and
a one-out-of-three social context (neutral, pleasure or
disgust expressions). This was done in order to test the
effect of facial expressions in each emotional condition. In
this analysis, the scores given to the pictures showing male
and female eater models were averaged. In order to better
understand interactions, we used other ANOVA models.
For example, we performed an ANOVA with context and
familiarity as within-subject factors and gender as a
between-subjects factor, for each type of product (familiar
vs. unfamiliar). Moreover, for each gender and level of
familiarity, we carried out a repeated measures one-way
ANOVA to determine the effect of context. The last fourway ANOVA (3*2*2*2) aimed to compare the three
emotional facial expressions and assessed the impact of
eater model and participant’s gender on meat eating desire,
as well as product familiarity and their interactions.
Results
Influence of participant’s gender and product familiarity on
the desire to eat meat in a non-social context
The repeated measures analysis of variance showed two
main effects: product familiarity, F(1, 86) ¼ 91.2, po0.
0001, indicating that the familiar products elicited more
desire to eat than the unfamiliar products (the first two
bars in Fig. 5a and b). However, there was also a main
effect of the participant’s gender, F(1, 86) ¼ 3.8, po0.05,
as well as a significant familiarity " gender interaction, F(1,
86) ¼ 4.0, po0.05. This interaction indicated that the
gender difference in the desire to eat meat products was
greater for the familiar meat products, F(1, 86) ¼ 6.0,
po0.01, than for the unfamiliar products, F(1, 86) ¼ 0.9,
po0.4 (Fig. 5a and b). Thus, men wanted to eat meat
products more than women, but only in the case of familiar
foods.
Comparison of the non-social and social context on the desire
to eat meat
Non-social vs. social contexts: neutral faces
Repeated measures analysis of variance showed two
marginally significant effects of the participant’s gender
and of the context without significant interaction between
these two factors, F(1, 86) ¼ 3.6, po0.06, F(1, 86) ¼ 3.3,
po0.07 and F(1, 86) ¼ 0.15, po0.7, respectively. Moreover, the context " familiarity and the context " participant’s gender " familiarity interactions were significant,
F(1, 86) ¼ 5.6, po0.01, F(1, 86) ¼ 16.3, po0.0001, respectively. To analyse this significant three-way interaction, we
ran two-way ANOVAs with context and participant’s
gender as factors for each product type taken separately.
For the familiar products, we observed a significant context
x gender interaction, F(1, 86) ¼ 4.7, po0.05. This interaction was due to the gender effect obtained in the non-social
context, F(1, 86) ¼ 6.0, po0.01, but not in the neutral
social context, F(1, 86) ¼ 1.8, po0.2 (the first four bars in
Fig. 5a). Taking each gender separately and considering
familiar products, the desire of men to eat in the presence
of a neutral face did not significantly differ from the desire
to eat in the non-social context, F(1, 43) ¼ 2.4, po0.2 (the
first and third bars in Fig. 5a). The same result was
observed in women, F(1, 43) ¼ 2.5, po0.2 (the second and
fourth bars in Fig. 5a).
For the unfamiliar products, only the social context
effect was significant, F(1, 86) ¼ 8.5, po0.001. Regardless
of the participants’ gender, the desire to eat unfamiliar
meats was higher when presented in the neutral social
context than in the non-social context (the first four bars in
Fig. 5b).
Non-social versus social contexts: faces expressing pleasure
The main effects of social context and product familiarity were highly significant, and that of participant’s
gender just significant: F(1, 86) ¼ 14.4, po0.001, F(1,
86) ¼ 14.4, po0.001 and F(1, 86) ¼ 4.0, po0.05, respectively. However, the context " familiarity interaction, as
well as the context " familiarity " participant’s gender
interaction were also significant: F(1, 86) ¼ 3.95, po0.05,
F(1, 86) ¼ 14.9, po0.001. When the products were
familiar, men liked them more than women, as seen above
in the non-social condition, F(1, 86) ¼ 6.0, po0.01, but
this gender difference disappeared when presented in a
pleasant social context, F(1, 86) ¼ 2.4, po0.2 (the first two
bars and the fifth and sixth bars in Fig. 5a). For men, the
context did not influence the desire score, F(1, 43) ¼ 0.15,
po0.7 (the first and fifth bars in Fig. 5a), whereas for
women, the pleasant faces increased the scores compared
to the non-social context, F(1, 43) ¼ 7.46, po0.01 (the
second and sixth bars in Fig. 5a). Conversely, when the
products were unfamiliar, there was no significant gender
difference in the non-social context, F(1, 86) ¼ 1.8, po0.2
(the first two bars in Fig. 5b). However, the gender
difference appeared when meats were presented in a
pleasant social context, F(1, 86) ¼ 4.0, po0.05 (the fifth
and sixth bars in Fig. 5b). Moreover, the changes in desire
to eat unfamiliar meat products in the presence of other
people expressing pleasure compared to the non-social
context was greater in men than in women: F(1, 43) ¼ 15.8,
po0.001 and F(1, 43) ¼ 4.5, po0.05, respectively.
Non-social versus social contexts: faces expressing disgust
The main effects of participant’s gender, social context
and their interaction were not significant: F(1, 86) ¼ 2.8,
po0.1, F(1, 86) ¼ 0.1, po0.8 and F(1, 86) ¼ 0.9, po0.4,
respectively. However, the context " familiarity and context " familiarity " participant’s gender interactions were
highly significant: F(1, 86) ¼ 9.3, po0.01 and F(1,
86) ¼ 12.3, po0.001. For familiar products, we observed
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Men
7
Women
6
Desire score
5
4
3
2
1
0
Non social
Neutrality
Pleasure
Disgust
Context
7
6
Men
Women
Desire score
5
4
3
2
1
0
Non social
Neutrality
Pleasure
Disgust
Context
Fig. 5. Effect of the neutral, pleasant and disgust social contexts compared to the non-social context on the desire to eat (a) familiar meats and (b)
unfamiliar meats in male and female participants. (Mean7Confidence Interval: 95%). – – – Line showing men’s desire to eat in non social context. – – –
Line showing women’s desire to eat in non social context.
a significant gender " context interaction. As for neutrality
and pleasure, there was a significant difference between
men and women in the non-social context, with women
having less desire to eat meat in this latter condition, but
not when meats were presented in a disgust social context,
F(1, 86) ¼ 1.2, po0.3 (the seventh and eighth bars in
Fig. 5a). This was due to the decreased desire of men to eat
familiar meat in the presence of disgusted faces, compared
to the non-social context, F(1, 43) ¼ 9.8, po0.01, whereas
the women maintained their lower desire to eat meat, F(1,
43) ¼ 0.17, po0.7. In contrast, no effect of gender, context
or their interaction was significant in the case of the
unfamiliar products. Thus, for the unfamiliar products, the
desire to eat meat remained low both in and not in the
presence of faces expressing disgust.
Comparison of the three emotional facial expressions on
desire to eat meat in the social context
The main effects of emotional facial expressions
(neutrality, pleasure and disgust) and of product familiarity
were highly significant on the desire to eat, F(2,
172) ¼ 13.3, po0.001 and F(1, 86) ¼ 78.5, po0.0001, but
the participant’s gender and eater’s gender had no major
effect. No two-way, three-way or four-way interactions
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8
S. Rousset et al. / Appetite ] (]]]]) ]]]–]]]
were significant except the familiarity " eater’s gender
interaction, F(1, 86) ¼ 5.6, po0.05. Thus, in the social
context, regardless of the facial emotion perceived, the
familiar meat products were preferred to unfamiliar meat
products (means 4.8 vs. 3.1). As expected, the two-by-two
face comparison showed that the disgusted faces produced
lower eating desire scores than those expressing pleasure
(means 3.7 vs. 4.2), F(1, 86) ¼ 14.6, po0.001 or neutrality
(means 3.7 vs. 3.9), F(1, 86) ¼ 11.1, po0.001. In contrast,
the faces expressing pleasure increased the level of eating
desire, compared to neutral facial expressions (means 4.2
vs. 3.9), F(1, 86) ¼ 11.8, po0.001. Moreover, the significant familiarity " eater’s gender interaction indicated that
regardless of the participants’ gender, unfamiliar meat
products received a higher eating desire score when a male
eater was shown (means 3.2 vs. 3.0), F(1, 86) ¼ 8.77,
p ¼ 0.004, whereas no difference between male and female
eaters was observed for the familiar products (means 4.8 vs.
4.8), F(1, 86) ¼ 0.03, p ¼ 0.86.
Discussion
In the non-social context, the present study showed that
the desire to eat meat was greater in men than in women in
the specific case of familiar meat products. This lower
desire in women might result from either disgust towards
sensory characteristics of meat or be related to health,
weight and/or ethical concerns (Audebert, Deiss, &
Rousset, 2006; Kubberød, Ueland, Roodbotten, Westad,
& Risvik, 2002; Lea & Worsley, 2002; Rousset, Deiss,
Juillard, Schlich, & Droit-Volet, 2005). Indeed, some
women reported disliking meat for its red colour, presence
of blood and the flesh that reminded them of dead animals
(Kubberød, Dingstad, Ueland, & Risvik, 2006; Lupton,
1996; Mooney & Walbourn, 2001). However, our study
revealed that when the meat products were unfamiliar, the
desire to eat meat also decreased in men who generally
liked meat, to the point that there was no longer any
observable difference between women and men in their
eating desire. This result was consistent with those showing
that lower liking is often observable for unfamiliar foods
and particularly unfamiliar meat products (Pliner &
Hobden, 1992; Pliner & Pelchat, 1991; Pliner et al., 1998).
It is of particular interest that our study suggested that
the perception of another person’s face modified the desire
to eat meat in both men and women. The present study
revealed that the observation of an unknown eater, even if
expressing a neutral emotion, increased the desire to eat
meat, and this to a greater extent for unfamiliar meat
products. Watching another person eating was thus
sufficient to increase the desire to eat. This result is
consistent with the modelling studies in which the model’s
behaviour (who ate more or less) influenced the amount of
food eaten by the participant who imitated the model’s
behaviour, independent of whether or not the participant
was on a diet or hungry (Goldman, Herman, & Polivy,
1991; Rosenthal & McSweeney, 1979). Although our study
deals with the desire to eat and not with the amount of
food eaten, it provided results consistent those of studies
showing the widely observed inclination of individuals to
eat in the same way as others did. According to Leary,
Tchividijian, and Kratxberger (1994), social intake norms
may be a strong determinant of eater’s behaviour, probably
stronger than physiological signals (hunger, satiety).
However, as stated by Herman et al. (2003), the modelling
effects remain a mystery.
The main contribution of our study was to demonstrate
that not only the presence of the eater models but the
emotion that they expressed affected the participants’
desire to eat. Indeed, the participants wanted to eat the
meat products more when they viewed the models with
expressions of pleasure than with neutral expressions.
Conversely, they had less desire to eat meat products when
the models showed expressions of disgust rather than
neutral ones. Thus, the pleasure faces could have suggested
to the participants that the food tasted good, and the
disgusted faces could have suggested that the food tasted
bad. Consciousness of such information should increase or
decrease individuals’ willingness to taste foods. However,
as explained in the introduction, a more automatic and less
conscious process could also be involved. According to
embodiment theory, the observation of emotions expressed
by other people’s faces induced the physiological reactions
associated with this emotion in the individuals (Barsalou et
al., 2003; Niedenthal et al., 2005). As suggested by
Dimberg (1982, 1990), the perception of positive and
negative facial expressions induces spontaneous mimicry
that in turn produces the corresponding emotional state
and influences the emotional attitude towards the context.
Thus, via an imitation process, the facial expressions of
others play an important role on our own emotions
(Adolphs et al., 2000; Décety & Chaminade, 2003; Gallese,
2003). Further investigations using electromyography
methods are now required in order to test whether eater
models’ facial expressions induce facial reactions in the
participants. Such a study might prove that the emotion
perceived in other people modulates the emotion elicited by
the food products themselves.
Our study also suggested that the influence of facial
expression on the desire to eat depended on the type of
food products and on the participant’s gender. In the case
of familiar meat products, compared to the eating desire
assessed in the non-social context, our results revealed that
positive emotion increased the desire to eat in the subjects
expressing a low eating desire (i.e., women), and the
negative emotion decreased this desire in the subjects
expressing a high eating desire (i.e., men). However, the
desire level in the presence of pleasant faces did not change
when the subjects (i.e., men) already liked the products. In
the same way, the desire level in the presence of disgusted
faces did not change when the subjects (i.e., women)
disliked them.
Regarding the desire of eating unfamiliar products in the
non-social context, the scores were similarly low in men
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S. Rousset et al. / Appetite ] (]]]]) ]]]–]]]
and women (lower than 3 out of 10). In the social context
of faces expressing pleasure, the scores given by men and
women were improved. However, men increased their
scores more than women. Thus, in a non-familiar situation
of unfamiliar food, men were more influenced by positive
facial information than women were. This raises the
question of the stronger inclination of men to follow the
group than women in the case of unfamiliar food products.
On the one hand, Klesges, Bartsch, Norwood, Kautzman,
and Haugrud (1984) found that social facilitation of eating
(increase in eating in the presence of others) is generally
stronger in men than in women. Moreover, one study by
Hobden and Pliner (1995) showed that when participants
had to choose between a novel and a familiar food product,
men chose novel foods more often than women, which is
consistent with our data. The behaviour of men towards
unfamiliar food may also be associated with their lower
risk perception in general. Men are less afraid, assess most
risks lower and worry about them less than women (Fagerli
& Wandel, 1999; Williams & Hammitt, 2001). Another
plausible reason might be that men may be more prone to
test unfamiliar meat because they like meat in general. In
contrast, women were more influenced by positive emotions for familiar rather than non-familiar meat products.
Because they did not like meat a lot, they might have had
little desire to try unfamiliar meat.
Surprisingly enough, the present study also suggested
that the social influence on the desire to eat meat products
varied as a function of the gender of the model observed.
Indeed, regardless of the participant’s gender, unfamiliar
meat products were judged as more desirable when the
other person eating these products was a man instead of a
woman. Few studies of social learning in humans have
considered the roles played by the gender of the individual
(Choleris & Kavaliers, 1999). As regards human eating
behaviour, Mory, Chaiken, and Pliner (1987) showed that
participants ate less when the eating companion was of the
opposite sex. Moreover, Pliner and Chaiken (1990) showed
that women ate less when the eating companion was a man
and when he was most desirable. Their behaviour may be
attributed to an attempt to convey an impression of
femininity. However, no study has yet focused on the
gender effect on desire/consumption of an unfamiliar food.
In the case of animals, Kawamura (1959) studied the
transmission of unfamiliar behaviours in Japanese monkeys, which suggested the existence of social constraints on
the channelling of socially mediated learning. When a
unfamiliar behaviour was invented by an adult male and
subsequently acquired by the dominant male, its transmission through the group was faster.
In conclusion, our study showed the influence of social
context on desire to eat meat products. Moreover, this
influence differed according to the familiarity of the
concerned food, the desire to eat meat products in a nonsocial context and the participant’s gender. Men were more
easily influenced than women by the social context of
pleasure in the case of unfamiliar meats, for which the
9
desire score was low in a non-social context. In contrast,
the social influence was stronger for women on their desire
to eat familiar rather than unfamiliar meats. Thus, it might
be easier to improve their desire to eat meat by using social
influence rather than by creating unfamiliar meat products.
Future research should seek to determine the effect of
facial expressions on the desire to eat a wider range of
foods such as palatable versus less palatable food products.
Further experiments should be done to compare the impact
of emotion and social context not only on the desire to eat,
but also on food liking in relation to consumption.
Acknowledgments
We are grateful to Benjamin Charpy for his valuable
photographic work, to E. Juillard for her technical
assistance, and to Stephanie Meritet and Alexandra
Tabouji-Beji (graduate students in ‘Statistics and data
treatment’) for the statistical analyses. This work was
supported by two grants, one from the Regional Council of
Burgundy and INRA DADP, and the second from the
Agence Nationale de la Recherche (ANR Blan06-2-145908
FaceExpress).
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