Evolutionary explanations for behaviour
Mental Disorders
Chiao and Blizinsky (2010) proposed gene-culture co- evolution theory to explain the higher prevalence of genetic susceptibility to depression in collectivistic societies
Altruism
There is a higher frequency of short alleles of 5-HTT in people in countries with collectivistic values
In collectivistic societies people report depression more rarely.
Short alleles of 5-HTT, the serotonin transporter gene, make people more vulnerable to stressful life events
Kin selection theory (Hamilton 1964) explains altruistic behaviour observed both in animals and humans and that the evolutionary meaning of altruism is the increase of survival of one's genes rather than an individual.
It predicts that altruistic acts will be more frequent in close relatives than in distant relatives.
Influence of emotion on cognition and behavior
Attachment
Theory of mind
Evolutionary Psychology’s Theory
STUDY: Evolutionary explanation for disgust
From the survival perspective, an organism maximizes its survival fitness if there is a balance between:
staying close to the attachment figures in unfamiliar, potentially dangerous situations
venturing outside and exploring the world to develop necessary life skills.
The ability to recognize the beliefs and intentions of others
It is possible to trace the evolution of this ability if we compare performance of animals and humans in the same tyYpes of tasks (Call and Tomasello, 2008)
As society becomes increasingly complex and survival depends on cooperation to a larger degree, it becomes important to understand the beliefs of others.
Influential evolutionary psychologists, Leda Cosmides and John Tooby, provide the following list of the field’s theoretical tenets (Tooby and Cosmides 2005):
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The brain is a computer designed by natural selection to extract information from the environment.
Individual human behavior is generated by this evolved computer in response to information it extracts from the environment. Understanding behavior requires articulating the cognitive programs that generate the behavior.
The cognitive programs of the human brain are adaptations. They exist because they produced behavior in our ancestors that enabled them to survive and reproduce.
The cognitive programs of the human brain may not be adaptive now; they were adaptive in ancestral environments.
Natural selection ensures that the brain is composed of many different special purpose programs and not a domain general architecture.
Describing the evolved computational architecture of our brains “allows a systematic understanding of cultural and social phenomena” (16–18).
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Our brain is hard-wired to produce a quick automatic reaction to fear stimuli, but this reaction can also be "overriden" in exceptional circumstances.
This may be linked to principles of natural selection because in limited time and dangerous situations it adds survival value to react quickly rather than deeply assess the situation.
Curtis, Aunger and Rabie (2004) published a study suggesting that disgust evolved as a protection from risk of disease.
There were a lot of challenges and possibilities of error, risking the evolutionary explanation the researchers were looking for. The responses and results had to lie within 5 certain hypotheses
First, respondents were asked a set of demographic questions on their age, sex, country, and so on. Then they were asked to rate 20 photographs for disgust on a scale from 1 (not disgusting) to 5 (very disgusting). Of these photographs, 14 comprised 7 pairs of disease-salient versus less salient stimuli.
Results supported all 5 hypotheses
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First, disease-salient stimuli were rated as more disgusting than less salient ones. For example, the plate of organic-looking fluid was rated as 61% more disgusting than the plate of
blue fluid that looked chemnical (ratings were 1.6 versus 2.6). For the towel pictures, the organic-looking substance produced much higher ratings of disgust than the blue chemical (1.6 versus 3.9).
Second, the results were consistent across cultures.
Third, females rated the disease-salient pictures as more disgusting than men. This was true for all the disease-salient pictures used in the study.
Finally, there was one question in the survey that asked participants to choose with whom they would be less likely to share a toothbrush. The average responses were ranged in the following order: postman (least likely), the boss, the weatherman, a sibling, a best friend, the spouse or partner. This shows that disgust is felt more strongly in contact with strangers than with relatives.
Fourth, as predicted, there was an age-based decline in the sensitivity to disease-salient stimuli.