Transcript Personality

The Evolution of
Personality
Victoria Thomas
Psyc 3906
Evolution of the Big Five
Personality are individual differences that
influence their cognitions, motivations, and
behaviors in various situations
 Differences are Variations
 Evolution is gene variability
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Variation Exists Because…
There is a normal variation around an
optimum
 The optimum value changes over time
 Frequency dependent selection will play a
role
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Why Does Variation Exist
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The ultimate source of variation is mutation
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When a trait is influenced by a single gene the trait
does not vary greatly since mutations arise relatively
infrequently
When a number of genes are involved in building a
trait the selection does not remove them
simultaneously
Therefore a trait that is affected by many genes will
have a significant amount of genetic variation
Optimum Fitness Levels
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We talked about this in class
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Hawks and Doves
Guppies and Prawns
There must be costs and benefits to each of
these traits
The benefits must increase reproductive
success when it exists in moderation
The costs must also increase reproductive
success when it exists in moderation
Big Five Personality Traits
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The Big Five Personality Traits are
classified into five categories
Extraversion
 Neuroticism
 Openness
 Conscientiousness
 Agreeableness
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Extraversion
This dimension is related to positive
emotion, exploratory activity and reward.
 Its proximate basis is thought to involve
variation in dopamine-mediated reward
circuits in the brain
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Extraversion
Benefits
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Positively related to
number of sexual
partners (reproductive
success)
More extramarital affairs
Higher sensation seeking
behaviour
Initiate more social
behaviour
More physically active
Undertake more
exploration of their
environment
Costs
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Higher rates of accident
and illness hospitalization
Suffer more from
traumatic injury
More related to criminal
and antisocial behaviour
Higher rates of risk in
general
Expose their children
more to step-parenting
(which is a risk factor for
the children)
Neuroticism
This trait is associated with various activity
levels and negative emotions
 Negative side effects are strong predictors
of psychiatric disorders and impaired
physical health
 It is a key predictor of relationship failure
and social isolation
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Neuroticism
Benefits
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Costs
Positively correlated with
competitiveness
Academic success is
positively correlated since
they are more resilient
Intelligence is positively
correlated with
neuroticism
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Intelligence has been
mentioned as a personality
trait however it is not part
of the Big Five
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High levels of anxiety,
depression and
schizophrenia
Low neuroticism has a
fitness disadvantage
because they lack
motivational striving and
hazard avoidance
Higher levels of risk
taking and therefore
higher risk of death
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Mount Everest Climbers
had high levels of
neuroticism
Openness
The Openness trait refers to openness to
new experiences
 People who have high levels of openness
believe more in paranormal activities and
phenomena
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Openness
Benefits
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Openness is
positively correlated
to creativity
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Females find creativity
in a mate important
Better at thinking in
abstract form
Costs
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Increased level of
schizophrenia
Associated with
depression and
psychotic delusions
Conscientiousness
This trait involves a high level of order and
self-control in pursuit of goals
 Immediate gratification is often delayed
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Conscientiousness
Benefits
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Better plan ahead and
has a positive life
expectancy
High levels of risky
behaviour avoidance
Healthy behaviours
Costs
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High levels of
delinquency and
antisocial behaviour
High levels of selfcontrol lead to missed
opportunities
Obsessive behaviours
have been linked to
high level of
conscientiousness
Agreeableness
Related to high levels of empathy and trust
 Low levels of agreeableness are related to
antisocial personality disorders
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Agreeableness
Benefits
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Live more
harmonious lives
Avoid violence and
interpersonal hostility
Low levels of
agreeableness
increase fitness when
they are few in
numbers
Costs
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Excessive trusting
can lead to decreased
fitness (reproduction
levels)
They invest much of
their energy into
others and not
themselves
In Summation
Fitness levels (reproductive success) are associated
with both the costs and benefits of the Big
Five Personality Factors
Both sides (costs and benefits) of every trait
(Extraversion, Neuroticism, Openness, Conscientiousness,
Agreeableness) are
beneficial when that trait is
rare in the population in question.
The End