EXTENDED ABSTRACT
How much a person eats has always been explained by an individual’s
hunger and satiety level (Vartanian et al., 2008). In the
1960s, scholars first discovered non-physiological factors would better
predict the amount of food a person will consume (Schachter et
al., 1968; Stunkard & Koch, 1964). Existing literature shows that
consumers’ food consumption behaviours are influenced by a number
of distinctive contextual cues. These can be divided into personal
contextual cues, consumption contextual cues, and food contextual
cues. Individuals often seek norms of appropriateness from these
contextual cues in eating events (Herman & Polivy, 2005). This research
manipulates social settings and portion size, which are identified
as important consumption contextual cues and food contextual
cues respectively. Other contextual cues are kept constant by using
an experimental method.
Consumer preferences and marketing efforts are largely characterised
by the advantages of larger portion size offerings (Dubois
et al., 2012). Portion size is widely recognised as having a profound
impact on the amount consumed (Zlatevska et al., 2014). In contrast,
it is less clear as to what effect eating with others has on the amount
consumed. Studies have reported people consumed both more and
less as a result of eating in a group (Herman et al., 2003). Most food
is offered in different portion sizes and consumed in a social setting.
Whether or not the effect of portion size will be influenced by social
setting remain unanswered.
This research aims to better understand how portion size and
social effects jointly affect the amount an individual is likely to consume.
The research questions include: Will there be an interaction
between portion size effect and social effect? Will personal characteristics
moderate the effect of portion size and social influence?
What is the effect of social influence when known context effects are
controlled? These research gaps in the existing literature are important
as both portion size and social effects are recognised as some of
the most important contextual cues in the literature. These contextual
cues were reported to have profound impact on an individual’s
consumption amount. The understanding of the combined effect, its
moderator, and directionality of these contextual cues is an important
advancement in the current knowledge. Social effect was reported to
be stronger for people with low self-esteem (McFerran et al., 2010).
Hermans and colleagues (2009; 2012) show mixed results regarding
correlations between restrained eating and amount consumed. Therefore,
personal contextual cues are measured to examine moderation
effect.
In the face of the possible bi-directionality of social influence on
the amount consumed by an individual, an experimental study design
was used to keep various other contextual cues constant. A cover
story was used in this research; participants signed up for a study
that explores consumers’ choices of holiday destination. Participants
were seated at a round table in a classroom, and were given some
group activities related to the cover story to induce rapport. Eating
was incidental to participating in this study. Participants signed up
for the experiment on a voluntary basis and were awarded course
credit. An experimental design with two (portion size: small, large)
by two (social setting: alone eating, social eating) between subject
design was used.
This research consisted of two studies using different types of
food. The food used in Study 1 was Arnott’s Nice cookies and the
food used in Study 2 was MARS M&M’s chocolates. The cookies
and chocolates in both studies were served in sealed, clear plastic
containers that were opened for the participants by the experimenter.
Each container was weighed before and after the experiment. In
Study 1 (cookies), results show that individuals’ consumption is affected
by the social setting (alone eating vs social eating), but not
portion size. In addition, social effect is moderated by portion size
effect. Restrained eating (but not self-esteem) moderated the effects
of social setting on the amount consumed by an individual. In Study
2 (chocolates), results show that individuals’ consumption is affected
by both the social setting (alone eating vs social eating) and portion
size. Self-esteem and restrained eating both moderated the effect of
portion size and social setting on consumption.
In Study 1 (cookies), portion size effect was moderated by social
effect. Given that portion size has been shown to have a profound
and robust impact on the amount consumed (Zlatevska et al,
2014), portion size effect was moderated by the effect of social setting,
which also has a great impact on consumption amount. This
finding is consistent with fixed-unit effect reported in Davis et al.’s
(2014) findings. They found that individuals consumed fixed units
of food regardless of the unit’s size when individuals are eating in a
group. However, in Study 2 (chocolates), both portion size and social
setting had an impact on the amount consumed by an individual. The
effects of portion size and social setting were independent and additive.
The relationship between portion size and social setting differs
in Study 1 and Study 2. This is explained by the difference in social
visibility for different food type used in each study. The cookies that
were used in Study 1 have higher social visibility compared to the
small sugar coated chocolates used in Study 2. Therefore, the amount
of cookies consumed by an individual is dependent on the social setting
but not portion size. On the other hand, the impact of social effect
and portion size effect in Study 2 are independent of each other.
The finding of the difference in the relationship between portion
size and social effects for Study 1 and Study 2 will help social marketers
promote healthy eating lifestyles. This can be achieved by encouraging
people to have their meals in a social setting; highlight the
importance of portion size effect when eating small unit sized junk
food in a social setting. We now know that social setting and portion
sizes interact only when the consumption behaviour of participants
is visible to others. When it is not visible, the two contextual cues
reduce to their main effects only.
History
Location
Hong Kong, China
Start date
2015-06-19
End date
2015-06-21
Publication classification
EN Other conference paper
Editor/Contributor(s)
Wan EW, Zhang M
Title of proceedings
Proceedings of the Asia Pacific Association for Consumer Research Conference 2015