Evolutionary and biological perspectives on personlaity Flashcards
What is the evolutionary theory of personality?
- Personality is useful for social dilemma
- Personality evolved as a spectrum as it is better for survival (more efficient species)
What did Nettle (2005, 2006) propose?
- Personality traits have ancestral costs and benefits e.g
Extraversion benefits - mating success, extraversion costs - exposure to high risk
What are the three contributions to any personality trait?
- Genetics
- Shared environment
- Non-shared environment
What is the evidence for personality genetics?
- Twin studies (MZ & DZ)
- Adoption studies
- 40-55% of variance explained by genetics
What evidence is there for genetic vs environmental differences in personality?
Studies of separated MZ twins show personality measures are about as similar as MZ twins raised together. No environmental influences as no shared environment?
What are the criticisms of studies suggesting genetic influences of personality?
Shared environment not considered:-
- MZ twins share same environment in the womb (stress, smoking, toxins..)
- MZ and DZ twins have post-natal shared environment
What did the Dutch Hunger Winter study show?
- Longitudinal study
- Showed that the children of the daughters of those who suffered during the hunger winter were far more likely to suffer from obesity and diabetes.
- Thought to be from genetic change in metabolism of fetus
What did McGue et al (1993 propose about changes in age?
- Environmental influences decrease with age
- Genetic influences increase with age
What neurotransmitters are thought to be connected to personality?
- Dopamine
- Serotonin
These studies can not be replicated and are not conclusive (polygenic - lots of genes are responsible)
What was Eysencks personality model?
2 diemnsions, Extraversion and neuroticism. Levels depended which catergory you were in:-
- Phlegmmatic
- Melancholic
- Sanguine
- Choleric
Spectrum modified by cortical arousal Ascending Reticular Activating System (ARAS)
Explain Eysenck’s Neuroticism and extraversion dimensions
Neuroticism
- Calm to nervous
- Genetically based
- Sympathetic nervous system (fight or flight)
Extraversion
- Shy, quiet to outgoing and loud
- balance between inhibition and excitation
What was the support for Eysenck’s model?
- Introverts choose lower levels of noise (naturally more aroused)
- Extraverts take more pauses during repetitive tasks (under aroused)
- Introverts require more depression drugs
What was Gray’s (1981) reformulation of Eysenck’s model?
- Behavioural Approach System (BAS)
- Behavioural Inhibition System (BIS)
- Added Impulsivity and anxiety as dimensions of personality
- High N & E = Impulsivity
- High N & low E = Anxiety
Explain BAS in Gray’s (1981) reinforcement sensitivity theory
- Underlying system for impulsivity
- Signals reward
- Triggers approach behaviour
- Associated with positive emotions
- Involves medial forebrain and lateral hypothalamus
Explain BIS in Gray’s (1981) reinforcement sensitivity theory
- Underlying system for anxiety
- Signals punishment
- Triggers inhibition and withdrawal from threat
- Associated with negative emotions
- Involves interaction of structures in septo-hypocampal system. Monoaminergic afferents from the brain stem and neocortical projection on frontal lobe
What support is there for Gray’s Reinforcement Sensitivity Theory?
- Revelle et al (1980)
- Introverts and extraverts effected differently by caffeine
- Showed time of day and impulsivity can reverse these effects
- Shows complexity of interaction between personality traits and situations
What did Haas et al (2008) find when looking for the neural correlates of personality?
- Higher N scores associated with MPFC when shown negative facial expression
- Not found for fearful of happy faces
- Evidence for relationship between N and negativity
What did Servaas et al (2013) find with regard to Haas’ work?
- Conducted a meta-analysis to identify brain regions associated with Neuroticism
- Found reproducible findings between negative and neutral images but not in PFC
