Disorders

Psychology 3916

Introduction

• You probably didn’t think you could use evolutionary theory to explain disorders

• Well you’re wrong!• It does not make these things any less

problematic than they are if we can understand the evolutionary underpinnings

• This work is in its infancy

Possible evolutionary explanations

• Some diorders may be defenses

• Side effects of fitness enhancing genes

• Frequency dependent selection

• Absence or malfunctioning of a module

• EEA and now

• Extremes of plygenetic traits

PTSD

• Should be more common in man made situations

• It is

• Ahh but there was always warfare

• But not with the type of weapons we have today

Depression

• Not just feeling down

• Length and severity are key

• Feelings of worthlessness

• Lack of motivation

Is it adaptive?

• Nesse’s idea

• Telling us we are going the wrong way so to speak

• Don’t expend resources, energy on stuff that won’t work

• You can see the adaptiveness here

• But you have to bounce back

Depression threshold

• Idea that when you ‘lose’ you feel bad

• You slow down then

• Maybe some people have way to low a depression threshold?

• Perhaps some have one that is too high too, not been really looked at

Is this a good explanation?

• Well depressed people may actually be a tad more accurate than non depressed!

• SAD

• Female vs. male differences in depression

Why is depression so common?

• EEA vs. today disconnect

• Number of relatives close by

• Jobs

• Power is not visible

• We compare ourselves to athletes, movie stars etc

Maybe depression is negotiation!

• Get help from kin, even though now they are not around

• Explains postpartum depression nicely

• New idea

suicide

• Hmm

• Not group selection

• Kin selection

• Suicide notes reflect this, that people feel they are a burden etc

Anxiety disorders

• Phobias for example• Phobias seem to be learned• However, nobody is afraid of houses or

cars• They are afraid of sharks and snakes• People are afraid of flying, not of

airplanes overhead, even if they have been through bombing

sociopaths

• Eww

• Might actually be a reproductive strategy, but only successful if rare

• Little shame or guilt

• Playing on reciprocal altruism

• Maybe give them an ‘outlet’

Autism Specrtum Disorders

• Characterized by a lack of social interaction, or poor interaction

• Repetitive beahviour

• Fixation on some characteristic or thing

• Many retarded, but not all (indeed the percentage seems to be going down in a way)

What is the evolutionary argument here?

• Theory of mind module

• ‘hyper male’ brain

• Kids of scientists are more likely to be autistic

• Boys are much more likely to be autistic than girls

Schizophrenia

• Does creativity go with Schizophrenia?

• Maybe not

• However, they have more creative relatives!

• Might be some relationship there

Conclusions

• This is early days but promising

• May lead to treatments

• Does not make it ‘all in the head’ or ‘normal’ or frankly better (morally) to be normal