AQA psychology

1. Tuesday, November 18, 2014
Evolutionary Explanations of
Food Preference
Starter:
In pairs: One of you is the taster and will be
blindfolded. The other will ensure the food
ends up in your mouth.
You need to:
Rate the food 1-10 (1 dislike- 10 like)
Try and identify the food
Of the foods you like explain why you
like them. What do they contain?
Candice Russell 2013

2. Sweet – identify foods rich in carbs to
provide us with energy
Sour – associated with food that has
gone off and therefore, should be
avoided
Salt – critical for functioning of the cells
and therefore need to identify
Bitter – associated with poisonous
plants, should be avoided
Umami – a recent discovery which is
highly savoury – a meaty taste

3. Humans split from the great apes about 6 million
years ago. Modern apes live on nuts, fruit and
plants. Therefore likely our early ancestors were
vegetarian.
However, we rapidly became omnivores due to the
receding forests about 2 million years ago and this
is evident in modern hunter gatherer societies.
Our digestive system is different from monkeys and
apes as theirs is specialised for the digestion of
plant material.

4. EEA: Environment of
evolutionary adaptation
EEA is the environment from where a species
first evolved.
As hunter gatherers we required high calorie
foods to ensure we could stay alive and live
to hunt another day. Our food supplies varied,
sometimes there would be feast other times
famine.
So by developing a preference for calorific
foods, ensures that we may have enough
energy stored in our bodies to survive if times
got tough.

5. Preference for Meat
Early hunter gatherers liked organ meat
These are high in protein
Milton (2008) claims this protein rich diet
contributed to the growth of the brain in
humans, and lead to our higher
intelligence.
Therefore, this all suggests that the
preference for savoury foods (umami) can
be traced back to our environment of
evolutionary adaptation (EEA)

6. Evaluation of meat and high calorie
preference.
Over to you: Summarise the preference
for high calorific food and meat, in 50 -75
Gibson and Wardle (2001)
words and no more.
Cordain et. Al. (2006)
Use the following terms: Environment
of evolutionary adaptation, natural
selection, survival, protein, amino aids,
Abrams (1987)
Read through page 90
and summarise the
research supporting
the preference for
calories .
Stanford (1999) Evidence from other primates
intelligence, brain development,
preference.
Are all food preferences a product of evolution?

7. Plenary: I have learnt that
One member of the class starts and says
one thing they have learnt, the next
member of the class repeats the previous
persons comment and then adds their
own, the third person says the previous
two members comments and then adds
their own………
Tough being the last person……
Try to add some research if you can!

8. Tuesday, November 18, 2014
Lesson 2: Taste Aversion
Why are these little cuties pulling
faces?
Why survival benefit does disliking sour
tastes confer?
What survival benefit does disliking
bitter tastes confer?
Candice Russell 2013

9. Why don’t we like bitter and
sour?
These receptor help us identify food that
has gone off
Leads to the facial expression of ‘disgust’
This is seen in human infants and other
primates
Suggests innate
This feeling leads to avoidance

10. Evidence supporting
evolution of bitter taste
aversion
Sandell and Breslin (2006) screened 35 adults for the
hTAS2R38 bitter taste receptor gene. The participants were
given a diet that contained vegetables with Glucosinolates.
Glucosinilates, are found in broccoli and Brussels sprouts and
when taken at really high doses can be toxic. Glucosinolate
also gives these vegetables their bitter taste.
Participants with the sensitive form of the gene found the
vegetable 60% more bitter then the insensitive form of the
gene.
Read Biological preparedness and explain how this aversion
lead to a survival advantage. (prepare to feedback)

11. Bait Shyness : Association
Bait Shyness: Rats given poison were not
being killed as they only took a small
amount, got ill and then associated the
illness with the bait.
Garcia (1955) gave saccharin to rats just
before exposing them to radiation. They
found after exposure the rats developed an
aversion to saccharin.

12. Aversion and chemotherapy
Read through the real world application
box on page 90.
Explain what neophobia is and how the
research by Bernstein and Webster
supports aversion as an adaptive
response.

13. Adaptive Advantage of Taste
Aversion
Taste and odour can be linked to taste
aversion.
The association can occur up to 24 hours
after the consumption of food. If you ever got food
poisoning from a restaurant, would you go back?
Why would this be advantageous to our
ancestors?

14. Medicine effect
If we associate a food with recovering from
an illness we may have preference for that
food.
Garcia et. Al (1955) Rats who were given
a distinctive flavour when given thiamine
injections developed a preference for that
Flavour.

15. Cultural Differences
Some food preferences such as sweet and
salty are universal.
What differences can you suggest?
Do these innate food preferences support
evolutionary theory?

16. Some Brief Evaluation
 Ignores the role of society, parenting and experience and
therefore a reductionist explanation
 Could explain the high rates of obesity, we are
programmed to like these foods. Still eating lots of
calories, even though we are now sedentary unlike our
hunter gatherer ancestors.
 We do show similarities to other species
 Fossil evidence (teeth, digestive system) provide
evidence of the shift to meat eating and hunter gatherer
societies
• Can explain unusual food preferences including morning
sickness
 explain taste aversion following illness and
chemotherapy
Nature rather than nurture

17. Over to you:
Write an IDA paragraph that has informed
commentary and evidence on taste aversion.
‘Evolutionary explanations of food preferences
are on the nature side of the nature nurture
debate. They argue that…………..’
Evidence for this comes from……this supports
the argument as…..
However evolutionary explanations to eating are
reductionist because other factors such
as……………. You will read these out in class

18. Lesson 3:
You have 15 minutes to complete a detailed plan
to group your ideas to together for the essay
‘Discuss evolutionary explanations for food
preference’
Show your plan to me, and I will give you
suggestions.
You will then need to complete your essay in the
remainder of lesson time.