Describe and evaluate the evolutionary explanation for food preferences (16 marks)
Evolutionary psychologists refer to the ‘ultimate explanation’ where current human eating
behaviours are explained by its adaptive purposes in our ancestral past, such as for energy
and strength, despite current food behaviours sometimes appearing as dysfunctional or
maladaptive. Preference for sweetness may have evolved as a result of sweet foods often
being high energy which is important for survival and the fight or flight response. Steiner
(1977) observed this by placing sugar on the tongues of young babies, who showed positive
facial expressions, despite not having been previously exposed to such foods. The fructose –
fast acting sugar – provides a quick energy release and is found in ripe fruit. Providing
evidence for an innate preference. Salt on the other hand is important for cell function.
Harris et al (1990) found that babies who had only been breastfed before, preferred saltier
cereal to plain cereal. They had no previous opportunity to learn a preference and no
previous exposure as breastmilk is not salty, again suggestion a genetic predisposition.
Neophobia and taste aversion are adaptive food preferences shaped by evolution.
Neophobia is the innate fear of new foods, emerging around ages 2–6, which protects
children from eating potentially harmful substances in the environment. It may be observed
as children avoid colourful foods, as this would normally be plants or animals warning us off
and indicating that they are poisonous. Particularly when children begin to pick foods out for
themselves and explore their environment without a parent, this is important as untried
food could be dangerous to health. Therefore neophobia is adaptive because we are less
likely to consume substances that could cause illness or death, according to Birch (1999).
Taste aversion is another evolved mechanism—if a food causes illness, even hours later, we
quickly develop a lasting aversion to it. Seligman (1971) explained this through biological
preparedness: humans are innately predisposed to fear things that posed a threat to
ancestors, such as poisonous foods. Steiner (1977) observed negative facial expressions of
babies responding to bitter tastes. This occurred before any learning of taste or preference
had occurred, strongly suggesting an innate mechanism at work. Usually, bitter tastes
indicate poison or food that could make us ill, identified by receptors on the tongue. It would
have been adaptive for our ancestors to detect this quickly and avoid these.
There is research support for the evolutionary explanation when referring to food
preferences. Torres et al (2008) found that during high period of stress, humans have a
tendency to prefer high fat foods, which would provide energy, and fuel the fight or flight
response. Increasing the chances of survival. This course of action in response to stress, fits
well with the ‘ultimate explanation’. Whereby food behaviours are predetermined by how it
would benefit our ancestors survival chances. It can’t however account for some people’s
preference for bitter foods such as soy sauce and grapefruit juice which may have been
found to have anti-carcinogenic properties. Instead an evolutionary psychologist would say
that we should avoid bitter food as its linked with poison. Therefore supporting the idea that
modern day food preferences result from past adaptive benefits for our ancestors.
The evolutionary explanation can also explain rising levels of obesity. Desor et al (1975) and
Steiner (1977) investigated babies’ food preferences according to facial expressions and
sucking behaviour. It was found that newborn babies have an innate preference for sweet
tasting food, rejecting bitter tasting foods. This innate preference for sweet foods may lead