Maternal diets prior to pregnancy, during pregnancy, and when breast feeding
can affect the taste preferences of neonates (Trout and Wetzel-Effinger 2012 ),
infants, and young children (Mennella 2014 ). Nutritional biomarkers from amniotic
fluid, breast milk, and formula can be used to assess prenatal and neonatal exposure
to specific dietary metabolites, nutrients, andflavors (Cooke and Fildes 2011 ; Trout
and Wetzel-Effinger 2012 ). Facial expressions and acceptance or rejection behav-
iors signal preferences in infants (Mennella 2014 ; Steiner 1979 ). Cross-culturally,
mothers use complementary foods to introduce and condition newflavor prefer-
ences in infants (Macbeth and Lowry 1997 ; Schwartz et al. 2013 ). Mennella ( 2014 )
presents a comprehensive review of this area including a number of studies
focusing on the early introduction of fruits and vegetables with a goal of estab-
lishing preferences for these foods as a strategy to counter preferences for processed
sweet and salty foods (Mennella and Trabulsi 2012 ).
Intentional/instructional and unintentional, visible and invisible information about
food preferences and individual, ethnic, social class, age, and gender-appropriate
eating styles are communicated by parents, siblings, teachers, peers, print, and elec-
tronic media (Dufour et al. 2012 ; Kittler and Sucher 2008 ; Pliner and Chaiken 1990 ).
Just as small differences in the physical environment (e.g., music tempo, lighting level,
food odors) can have profound effects on consumption patterns and amount eaten
(Wansink 2010 ), so can small changes in the social environment. For example, people
consumed more food in a restaurant when they were eating with other people: about
35% more with one person, 75% more with 4 people, and 95% more with 7 or more
people (Bell and Pliner 2003 ; Wansink2004b, 2010 ). Experimental evidence indicates
that people unconsciously monitor and mimic eating pacesetters (Wansink 2010 ).
Social network analysis has delineated the long-term roles of spouses, siblings, friends,
and neighbors on eating patterns and body weight (Christakis and Fowler 2007 ;
Pachucki et al. 2011 ). Using the large, longitudinal Framingham Heart Study database,
Christakis and Fowler ( 2007 ) found that a person’s chances of becoming obese
increased by 57% if he or she had a friend who became obese, 40% if one’ssibling
became obese and 37% if one’s spouse became obese.
A possible neurological substrate influencing both short-term mimicking of eating
behaviors and the role of social networks and social cognition in body size and weight
are the Von Economo neurons (VENs) (Allman et al. 2011 ; Stimpson et al. 2011 ).
These distinctive neurons are present in the anterior cingulate (ACC) and
fronto-insular (FI) cortex, both areas related to goal-directed behaviors, such as eating.
They are unique to species with both large brains and complex social systems, pos-
sibly representing convergent evolution as an adaptation to rapid transmission of
socially relevant information. For example, VENs are activated by a number of
emotions: embarrassment, resentment, and empathy (Allman et al. 2011 ). Recent
evidence indicates that protein expression in the VENs regulates gut and immune
function, linking visceral feelings and appetite control to self-awareness and social
reciprocity, i.e.,‘having a gut feeling about someone or some situation’(Stimpson
et al. 2011 ). Biomarkers include morphological features of size, location, and density
of VENs and neurophysiological function as monitored using functional magnetic
resonance imaging (fMRI) or positron emission tomography (PET).
208 L.S. Lieberman