Evolutionary Explanations Flashcards
How many main food groups are there?
5
Name the 5 main food groups
1) Sweet
2) Sour
3) Salt
4) Bitter
5) Umami
What are sweet foods?
Foods rich in carbs to provide us with energy
What are sour foods?
Associated with food that has gone off and therefore should be avoided
What are salty foods?
Critical for functioning of cells and therefore need to identify
What are bitter foods?
Associated with poisonous plants so should be avoided
What are umami foods?
Highly savoury, meaty taste
What are the 2 main evolutionary explanations of food preference?
1) Environment of Evolutionary Adaptation (EEA)
2) Taste aversion
Outline the Environment of Evolutionary Adaptation (EEA)
Refers to the environment in which a species first evolved - human beings first emerged as a separate species 2 million years ago on African savannah, and natural selection favoured adaptations geared toward survival in that particular environment - for most of our evolutionary history, we have probably lived in hunter-gatherer societies
Outline human beings’ early diets
Diets included the animals and plants that were part of their natural environment - preferences for fatty food would have been adaptive for early humans as conditions of EEA meant energy resources were vital to stay alive - although modern humans more concerned about nutritious value of food, instead what we eat is often rich in calories but not particularly nutritious - in the EEA, calories were not as plentiful as they are today, so it makes sense humans have evolved a distinct preference for foods that are particularly rich in calories
Outline meat preference
Humans began to include meat in their diets to compensate for a decline in the quality of plant foods - fossil evidence suggests daily diet was derived primarily from animal-based foods, in particular animal organs that are extremely rich sources of energy - a meat diet, full of densely packed nutrients, provided the catalyst for the growth of the brain - meat supplied early humans with all essential amino acids, minerals and nutrients they required, allowing them to supplement their diet with marginal, low-quality plant-based foods that have few nutrients but lots of calories, like rice and wheat
Outline Milton (08)
Without animals, unlikely early humans could have secured enough nutrition from a vegetarian diet to evolve into active and intelligent creates they became
How was the idea of taste aversion created?
First discovered by farmers trying to rid themselves of rats and they found it was difficult to kill rats by using poisoned bait because rats would only take a small amount of any new food and if they became ill, would rapidly learn to avoid it
What is the main study for taste aversion?
Garcia (55)
Outline Garcia (55)
Rats who had been made ill trough radiation shortly after eating saccharin developed an aversion to it and very quickly associated their illness with the saccharin
What are the adaptive advantages of taste aversion?
It would have helped our ancestors because if lucky enough to survive eating poisoned food, they would not make the same mistake again - once learned, such aversion are hard to shift, an adaptive quality designed to keep our ancestors alive
What is the second part of taste aversion?
The Medicine effect
Outline the medicine effect
There is also evidence that animals can learn a preference that makes them healthier, with any food eaten just before recovery from illness being preferred in the future
What is the main study supporting the medicine effect?
Garcia (55)
Outline Garcia (55) for the medicine effect
Found when distinctive flavour is presented to thiamine-efficient rat and then followed by an injection of thiamine, the animal will acquire a preference for that flavour
What is the study that investigated the kinds of choices children make abot their diet?
Davis (28)
Outline Davis (28)
When this study happened, it was at a time when feeding policies typically imposed a highly restricted feeding regime - children who were living in paediatric unit in USA for several months were offered range of 10-12 healthy foods prepared without sugar, salt or seasoning and were free to eat what they liked - they observed and recorded which foods they chose - findings indicated that children were able to select diet that was consistent with growth and health, and no feeding problem were observed - formed basis of a ‘wisdom of the body’ theory
Name 4 evaluative points about Davis (28)
1) Naturalistic yet controlled environments so reflect daily lives
2) Findings have been used to support different sides of same argument
3) Results have been published in a prestigious peer-reviewed medical journal and cited by researchers
4) Suggests food preferences changes over time and were modified by experience
How have the findings from Davis (28) been used to support different sides of same argument?
They highlight wisdom of body and existence of biological drives - can also be used to demonstrate importance of environment, since types of foods offered were restricted and healthy