10/04/2023 Evolutionary Explanations 1

Evolutionary Explanations of Food Preferences

Do we have an innate preference for certain foods?

How were these preferences adaptive in the EEA?

How do these preferences function now?

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Background

• The environment of Evolutionary Adaption (EEA) is the environment in which a species first evolved

• Humans emerged 2 million years ago on the African Savannah

• Natural selection favoured traits which allowed survival in that environment

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Evolutionary Explanations of Food Preferences

• Any current behaviours that appear to be maladaptive (dysfunctional) can often be explained as being functional in the past

• Our modern preference for calorific food can be traced back to our ancestors where it was adaptive

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• Early humans were frugivores and relied on sweet fruits for their survival

• Harris (1987) – babies like sweet tastes

How are innate food preferences adaptive: Sweet

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How are innate food preferences adaptive: Salty

• In the hot African Savannah salty food would have been needed to replace salts lost through sweating

• Denton (1982) – animal research has shown innate preference for salty food

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How are innate food preferences adaptive: Umami

• Receding forests meant people had to start eating meat

• Inclusion of meat acted as a catalyst for brain growth

• Milton (2008) humans would never have evolved to become active, intelligent creatures without meat in their diet

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How are innate food preferences adaptive: Sour

• Discouraged people from eating foods that had gone off

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How are innate food preferences adaptive: Bitter

• Discouraged people from eating potentially poisonous food

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How are innate food preferences adaptive: Fatty

• Needed in EEA as high levels of energy needed to survive

• Burnham and Phelan (2000) preference for fatty foods come from times of food scarcity when this type of food is full of energy giving calories

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How are innate food preferences adaptive: Spicy

• Sherman and Hash (2001) – meat dishes contain far more spices than vegetable ones

• Spices have antimicrobial properties

• Could explain preferences for spices in hot countries

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Food Neophobia

• Animals tend to avoid food they have not come across before

• Frost (2006) As a food becomes more familiar we show a greater liking of it

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Taste Aversion Learning

• Developed as a means of survival

• If we eat food that makes us sick it would be an advantage to avoid that food in the future

• Garcia et al (1955) rats made ill through radiation after eating saccharin developed an aversion to it

• Explains why food poisoning leads to inability to eat that food for a long time (association)

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Innate food preferences in the modern world

• Our food focus is no longer about eating enough to avoid malnutrition as it was in the past

• Our preference for sweet food can now lead to a highly calorific diet (chocolate, sugar)

• Our preference for salty food can now lead to a highly fatty diet (crisps, chips)

• • •

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Evaluation

• Good explanation of food preferences– i.e. good explanation of why we like foods

which have very little goodness

• Focus on ultimate rather than proximate causes– i.e. evolutionary approach considers

ultimate causes rather than looking at maladaptiveness (overeating)

– Genome Lag

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Evaluation

• Research– Difficult to falsify– However, we can study related species who face

similar adaptive problems to our ancestors– Fossils show the evolution of meat eating

• Suggests evolution has stopped though Wills (1999) say this is not the case

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IDA

• Reductionist

• Determinist

• Cultural Differences– Infant preferences of sweet food is universal– However, after infancy there is a broad range of likes

and dislikes– Evolved factors are modified by experiences made

available by our culture

• Supports Nature-Nurture debate