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Evolutionary explanations of eating behaviour (24 marks)

Outline and Evaluate Evolutionary Explanations of Eating Behaviour (24 marks)

The evolutionary explanation uses the Environment of Evolutionary Adaptation (EEA) as a model to explain eating behaviours and food preferences today. In this environment, psychologists believe humans have a preference for fatty organs such as brains or the liver. Milton claims that this was adaptive because the fatty food contained lots of nutrients and protein for growth which allowed our brains to grow and develop sophisticated cognitive functions and this cannot be done on a diet of only fruit and vegetables.

There is research support for the theory of why we have a preference for fatty food. Gibson and Wardle presented children with a variety of fruits and found that the vast majority chose bananas and potatoes which are dense in calories. This therefore demonstrates that we are hard-wired to pick out the foods with the most calories in order to enhance survival. This theory has real world applicability as it explains why we prefer to eat food such as pizza and burgers instead of vegetables and fruit. This theory is also supported by Stanford who found chimpanzees who had been near starvation chose the fattiest parts on the kill such as the brain in order to regain the calories they had lost. Therefore, this provides valid evidence to support the theory that humans have a preference for fatty food as it aids survival.

However, there are cultural differences that affect our preferences for certain food. For instance, in China they eat a lot of rice and noodles, but this could be down to the availability of the food. Therefore, we can say that evolved factors are still important today, but these are modified by our experiences with different foods; with culture partially determining the degree of such experiences. As a result of this, nowadays evolutionary preference is not universal.

The evolutionary approach also uses the EEA to explain taste aversion in humans. Rats are difficult to poison because they have evolved to be ‘Bait Shy’ which means they only taste a small bit of food and if it makes them ill they avoid it. The same is seen in humans who naturally avoid smelly or sour food which is beneficial because it means the body is protected from unhealthy or poisonous food. This is supported by Garcia et al. They found that rats who were given a distinct flavour before suffering radiation poisoning avoided the food after becoming ill. This is adaptive because it means the rats that eat a small amount of poison don’t get ill, therefore survive. This is an evolutionary advantage because those who don’t have ‘Bait Shyness’ are most likely to die from eating bad foods. This supports the evolutionary explanation and explains why humans have evolved not to like certain foods that are sour. However, the results from this study may not be able to be generalised due to the type of sample used. Humans and rats are two different types of species therefore can we really apply the results of this study to the complex behaviour of humans? Therefore, the validity of this study can be questioned making it not a suitable explanation for the reason why humans decide to avoid certain food.

Despite this, Sandell and Breslin’s study supports the evolutionary theory of taste aversion in humans. They asked 33 participants (pps.) to rate foods in order of bitterness. Some vegetables contained Glucosinolates which in high doses can be poisonous and taste 60% more bitter than other flavours. The participants stated the food containing Glucosinolates tasted the most bitter. This shows humans have naturally evolved to pick out bitter tastes and then avoid the food to aid survival. Thus, this study supports the evolutionary explanation of why we avoid certain foods.

All in all, the evolutionary theory is reductionist. It reduces complex reasons for our food tastes down to evolutionary hardwiring. Such an ultimate approach may be useful in terms of implications- for helping those with obesity and poor eating habits for example. However, more proximate explanations may be more useful in explaining why we are attracted to McDonald’s type of fatty foods. Proximate explanations such as advertising techniques and branding used to sell such foods cannot be ignored and would be let off lightly if we put the obesity epidemic down to evolutionary factors alone.

This approach is also determinist as it suggests we have no free will and have to eat fatty and sweet foods. In fact many people are vegetarians and decide to eat healthy. It therefore ignores cognitive factors and how we make decisions that all influences our preferences for certain food.


17/24 Grade A AQA A

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