Biological/Evolutionary Perspective

what aspects of the brain can be examined with technology?

anatomy: functions of parts of the brain

biochemistry: effects of neurotransmitters and hormones on brain processes

*both related to personality and behavior

what research methods are used for studying the brain

brain damage (Phineas Gage, lesions)

Brain stimulation (mostly animals, transcranial magnetic stimulation)

brain activity and imaging

• (detect WHEN brain is working, EEG, MEG)

• (detect WHAT parts of brain are working, PET, fMRI)

what difficulties are associated with imaging techniques?

all parts of the brain are always active to some degree, brain activity in response to stimuli does not mean the same psychological process occurs every time the area is active, difficult and expensive

the amygdala

links perception with thoughts and emotions

role in negative/positive emotions, assessing threats and rewards

relevant for motivation

what brain functions are associated with the frontal lobes and neocortex?

higher cognitive functions

emotion

social and emotional understanding

self-control, impulse control, regulation of feelings

what emotions are associated with the left frontal lobe?

pleasant emotions, approach (vs withdraw), inhibition of reactions to unpleasant stimuli, emotional stability, propensity to get angry

what emotions are associated with the right frontal lobe?

unpleasant emotions, withdrawal, neuroticism

somatic marker hypothesis

emotional processes guide decision making by making somatic markers (bodily signals associated with emotions)

what brain functions are associated with the anterior cingulate?

important for experiencing normal emotions, controlling emotional and behavior impulses, possible implications for positive and negative affective differences between extraversion and neuroticism

what brain systems are associated with persistence?

frontal cortex and striatum

what brain areas make up the C-system?

lateral PFC, hippocampus, medial temporal lobe, posterior parietal cortex

**plays a role in effortful and reflective thinking in oneself and other

what brain areas make up the X-system ?

vmPFC, amygdala, lateral temporal cortex

** plays a role in effortful and reflective social thought

neural context effect

more important to look at complex processes in brain than to focus on one area in the brain to understand what a complex process is

• making a decision, performing a behavior, experiencing an emotion

neurons vs hormones

neurons communicate with neurotransmitters

hormones stimulate or inhibit neural activity

Eysenck’s biological basis of personality

differences in personality (introvert vs extravert) are due to differences in activation of the cerebral cortex

ARAS (Ascending Reticular Activating System)

Low ARAS resting activity - extraversion (less sensitive, need more activation)

High ARA resting activity - introversion (more sensitive, less activation)

how do introverts and extroverts differ in drug effects according to Eysenck’s biological basis of personality?

introverts have higher cortical arousal, so need more of a depressant drug to reach level of non-alertness

extraverts seek stimulation and consume more simulating foods and beverages

neuroticism according to Eysenck’s biological basis of personality

arousal is related to the sympathetic nervous system (fight or flight in spinal cord)

neurotic: low arousal, takes little to stress them out

emotionally stable: high arousal, more difficult to stress them out

where are hormones produced?

gonads and adrenal cortex

when are epinephrine and norepinephrine released?

in response to stress; creates fight or flight response

females have tendency to respond to stress as tend and befriend

psychoticism according to Eysenck’s biological basis of personality

related to testosterone levels

associated with aggression and criminality (most criminals male, 10x higher concentration in male)

role in control and inhibition of aggression and sexuality

levels decrease in men after marriage and rise after divorce

how does testosterone affect personality?

essential developmental hormone that is believed to change the brain which can cause behavioral differences → more aggression

what is the role of dopamine as a neurotransmitter?

involved in responding to rewards and attractive objects/people

related to sociability, general activity level, and fundamental personality dimension of plasticity

associated with extraversion, openness, and possible bipolar disorder and impulsivity

there are individual differences in developments of neurons that produce and are responsive to dopamine

what is the role of serotonin as a neurotransmitter ?

plays a role in inhibition of behavioral impulses

what is Prozac and what side effects does it have?

a selective serotonin reuptake inhibitor (SSRI)

physical effect: increases serotonin levels

psychological effect: changes in personality for people without a diagnosed disorder, makes negative emotions less severe without affecting positive emotions

What theories are included in Gray’s biological explanation of personality (1987)?

BAS (Behavioral activation system)

BIS (Behavioral inhibition system)

BAS

individual differences in sensitivity to reward

activation causes release of dopamine

strong BAS → high impulsivity, extreme novelty seekers

linked to positive emotionality

BIS

individual differences in sensitivity to novelty and punishment

BIS activation→ lower levels of serotonin

strong BIS→ fearful, insecure, cautious

linked to negative emotionality

reinforcement sensitivity theory (Gray)

1. BAS: reward system

   1. approach behavior and anticipatory pleasure

   2. cerebral cortex. thalamus, striatum

2. BIS: punishment system

   1. avoidance behavior

   2. brain stem, neocortical projections to the frontal lobe

3. Fight-flight-freeze system: threat system

   1. sympathetic nervous system

behavioral genetics

examine how genes influence broad patterns of behavior

address how personality traits are shared among biological relative

why are twin studies important for biological personality?

allows for examination of environmental influence and genetic influence

what is the heritability coefficient?

[r(mz) - r(dz)] x2

Theory of inheritance of acquired characteristics

direct inheritance of characteristic developed over parent’s lifetime

ex: giraffes responded to taller trees by stretching their necks to be able to eat

all acquired characteristics are inherited to the next generation

Jean Baptiste Lamarck

Natural Selection

variation seen in a species is due to genetic differences; certain genes are more adaptive in certain environments; genes that ensure survival are passed down

Charles Darwin

how does variation occur in natural selection?

mutations in genes

adaptive fitness

greater adaptive fitness leads to higher chance of survival and reproduction which passes the favorable traits onto the next generation

Do personality traits contribute to adaptive fitness?

extraversion → CNS that motivates us to pursue rewards → adaptive fitness

extraverts are also more impulsive and might not survive as long as introverts which is why there are both

balancing selection

both ends of the continuum offer adaptive fitness in different ways or under different conditions

frequency- dependent selection

individuals compete for a resource using

1. hawks compete aggressively

2. doves give in as soon as they encounter aggression

neither is evolutionary stable; need both

what is a main question for sociobiologists?

how might have behavior patterns become built into our genetic codes?

sociobiology and altruism

altruism: tendency to act for the welfare of others to the point of sacrificing one’s own well-being for another

helping/saving relatives helps aspects of your genetic makeup be passed on (kin selection)

environment of evolutionary adaptiveness (EEA)

the environment to which a species is adapted

animals that lived in different environments or survived in different ways faced different reproductive problems (not all the same)

biological reductionism

a theoretical approach that aims to explain all social or cultural phenomena in biological terms and denies any causal autonomy
ex: differences in sexes and their abilities or tendencies

what are some problems with evolutionary psychology?

highly speculative, complete assessment directly from genes will not occur soon, personality is very complex and individual