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Eating: Evolution and eating introduction A2


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Eating: Evolution and eating introduction A2

  1. 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? 08/10/2013 Evolutionary Explanations 1
  2. 2. 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 08/10/2013 Evolutionary Explanations 2
  3. 3. 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 08/10/2013 Evolutionary Explanations 3
  4. 4. • 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 08/10/2013 Evolutionary Explanations 4
  5. 5. 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 08/10/2013 Evolutionary Explanations 5
  6. 6. 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 08/10/2013 Evolutionary Explanations 6
  7. 7. How are innate food preferences adaptive: Sour • Discouraged people from eating foods that had gone off 08/10/2013 Evolutionary Explanations 7
  8. 8. How are innate food preferences adaptive: Bitter • Discouraged people from eating potentially poisonous food 08/10/2013 Evolutionary Explanations 8
  9. 9. 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 08/10/2013 Evolutionary Explanations 9
  10. 10. 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 08/10/2013 Evolutionary Explanations 10
  11. 11. 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 08/10/2013 Evolutionary Explanations 11
  12. 12. 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) 08/10/2013 Evolutionary Explanations 12
  13. 13. 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) • • • 08/10/2013 Evolutionary Explanations 13
  14. 14. 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 08/10/2013 Evolutionary Explanations 14
  15. 15. 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 08/10/2013 Evolutionary Explanations 15
  16. 16. 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 08/10/2013 Evolutionary Explanations 16