lecture 2 Flashcards
what are the 3 domains in Eysenck’s PEN theory?
psychoticism
extraversion
neuroticism
what does it mean by domains are orthogonal?
they are statistically independent- one trait does not affect the other
what are the four sources of support for Eysenck’s PEN theory?
psychometric evidence
biological basis
theoretically plausible
predictive of social issues
what are the two types of extraversion?
introvert
extrovert
what are the two types of neuroticism?
neurotic
emotionally stable
what are the two types of psychoticism?
psychopath
sociable
what is the difference between psychoticism and the other domains?
exhibits a skewed, not a normal, distribution
what is the key assumption for the biological basis for personality?
personality traits reflect individual differences in brain structure and function
what are the key regions of the brain involved in personality?
reticular formation and ARAS
cortex
limbic system
what is the reticular formation and ARAS?
networks of nuclei located in the brainstem
includes ascending pathways to the cortex (ARAS) and descending pathways to the spinal cord
what is the cortex?
outermost layer of the brain
contains sensory, motor and association areas
what is the limbic system?
‘deep’ brain structures, such as the hippocampus and the amygdala
involved in emotional processing and homeostasis
what are the two arousal systems?
reticulo-cortical circuit
limbic system
which domain is the reticulo-cortical circuit related to?
extraversion
which domain is the limbic system related to?
neuroticism
how does the reticulo cortical circuit control extraversion?
controls the ortical arousal generated by incoming stimuli
ARAS acts as a gate- controls overall arousal levels
introverts display higher levels of activity in the ARAS- let too much in- seek situations with low stimulation (opposite for extroverts)
what shape can the relationship between performance and arousal be represented by?
inverted U shape
how does the limbic system control neuroticism?
controls the response to emotional stimuli
more aroused in neurotic individuals in emotion enducing situations
how does the limbic system relate to the limbic system/neuroticism?
limbic system regulate the sympathetic nervous system- part of the automatic nervous system producing involuntary responses
sympathetic nervous system is in charge of the body’s fight or flight
remains constantly active at a basic level to maintain homeostasis
high neuroticism= hypersensitivity in the sympathetic nervous system- react more strongly to potentially threatening situations
increased limbic system activation needed to regulate their response
what is the biological origin of psychoticism?
originally unspecified- possibly related to the regulation of serotonin or dopamine or sex hormones
recently- thought to be the amygdala- brain’s fear centre- psychopathy characterised by extremely low fear
what is reliability?
the measurements are consistent
what is validity?
the measurements represent true findings
who used questionnaires to investigate the PEN model?
Eysenck, Eysenck and Barrett, 1985
what is the short scale EPQ-R?
48 questions
answered with a yes/no response
12 for each domain, and an additional 12 to assess for honest responses
what do you expect the results to be for the short scale EPQ-R?
reliability across repetition
high similarity within scales/domains
low similarity between scales/domains
what was found with the results for the short-scale EPQ-R? (Eysenck et al, 1985)
within domains: good internal consistency for extraversion and neuroticism (approx 0.85), but questionable for psychoticism (approx 0.6)
between domains: orthogonal- didn’t correlate with each other
what is the alternative model to Eysenck’s PEN theory?
Gray’s Reinforcement Sensitivity Theory
what did Gray conduct research using?
animals
what did Gray agree with Eysenck about?
personality traits have a psychological basis
what is Gray’s reinforcement theory?
differences in personality differ from the extent to which people respond to rewards/punishment
what is the result if people are highly sensitive to positive reinforcement?
tend to seek rewards and positive experience
learn faster when offered pleasant stimuli
what does it mean if people are highly sensitive to negative reinforcement?
tend to avoid punishment and negative experiences
learn faster when there are aversive stimuli
what are the three independent systems Gray (1982) proposes?
behavioural activation system
behavioural inhibition system
fight-flight system
what is the behavioural activation system?
sensitive to rewards and pleasant stimuli
behaviours are approach and impulsivity
mediated by dopamine
what is the behavioural inhibition system?
sensitive to punishment and aversive stimuli
behaviours are avoidance and anxiety
mediated by noradrenaline and serotonin
septo-hippocampal pathway
what is the fight-flight system?
unconditioned response and fear
sympathetic nervous system
how does Gray’s model relate to Eysenck’s model?
30 degree rotation- can use one system to predict where a person would be with a different trait
how can we measure BAS using questionnaires?
three different subscales: reward responsiveness, drive and fun seeking
who revisited RST?
Gray and McNaughton (2000)
how was the behavioural activation system modified?
largely unchanged
sensitive to conditioned and unconditioned responses to reward
how was the fight-flight system modified?
now the fight-flight-freeze system
avoidance and escape system in threatening situations
sensitive to conditioned and unconditioned stimuli
fear association
how was the behavioural inhibition system modified?
resolves the conflict between the FFFS and the BAS
what are the key assumptions of both models?
personality traits reflect individual differences in brain structure and function
what questions do we want to answer when evaluating both models?
do the traits described by the models have a biological basis?
are the biological bases accurately described by the models?
what are the four ways we can assess whether the models have a biological basis?
temporal stability
similarity across species
cross cultural evidence
hereditary/genetic contributions: behavioural genetics
what was found about temporal stability for the PEN model?
Costa and McCrae (1994)
meta analysis
extraversion stable within participants, correlation of 0.64, no substantial cross sectional age differences
neuroticism stable within participants, correlation of 0.64, substantial cross sectional age differences in women
didn’t investigate psychoticism, but less stability reported for this trait
what was found about temporal stability for the RST model?
Carver and White (1994)- test-retest reliability of the BAS-BIS questionnaires after 8 weeks were between 0.59-0.69
only an acceptable correlation and only 8 weeks later= issue
what was found about similarity across species for the PEN model?
Gosling and John (1999)
reviewed 19 studies which examined the presence of extraversion and neuroticism in 12 animal species
many, but not all, displayed extravert and neurotic behaviour
what was found about similarity across species for the RST model?
Gray (1970) extrapolated findings to humans
showed that rats have separate systems controlling their behaviour in reaction to rewarding/punishing stimuli
how can we improve studying animals?
inter-rater reliability
test-retest reliability
what is inter rater reliability for animals?
do raters agree when classifying animal’s personalities
what is test-retest reliability for studying animals?
do the animals show the same personalities at different points in time
what was found about cross cultural evidence for the PEN model?
Barrett et al (1998)
EPQ-R in 34 countries- domains were grouped similarly across cultures
Caruso et al (2001)
internal consistency of the four domains from datasets in different countries
internal consistency good for extraversion and neuroticism, but questionable for psychoticism
what was found about cross cultural evidence for RST?
similar values of internal consistency have been found across different countries
how can we assess hereditary or genetic contributions?
compare traits in biologically and non biologically related family members
what are identical twins?
monozygotic
100% shared DNA
100% shared environment
what are non identical twins?
dizygotic
50% shared DNA
100% shared environment
what was found about PEN for behavioural genetics?
Plomin et al (1994)
heritability accounts for 51% for extraversion and 46% for neuroticism
what was found about RST for behavioural genetics?
Takashaki et al (2007)
during childhood and adolescence, stable genetic influences on BAS and BIS
what are characteristic gene studies?
associations between genetic variation within genes of interest, and specific traits
ed to BAS scores
what is the issue with candidate gene studies?
many of the findings were not replicated
most genes are polygenic- influenced by multiple genes
what are genome wide association studies?
looking at millions of SNPs across the entire genome
what are SNPs?
single nucleotide polymorphisms
most common type of genetic variation amongst people
represent a difference in a single DNA building block (nucleotide)
what is the issue with genome wide association studies?
method requires many comparisons
need to avoid a Type I error
this sets a very high threshold for significant results, so significant results are obtained from very large thresholds
what are examples of structural brain measures?
cortical thickness
volume/surface area
gyrification
what is cortical thickness?
the grey matter between the pial and white surface
what is gyrification?
folding of the cortex
who investigated the link between cortical thickness and extraversion/neuroticism?
Wright et al, 2006
what did Wright et al find out about cortical thickness?
measured cortical thickness to look at the neuroanatomical correlates of extraversion and neuroticism
extraversion negatively correlated with cortical thickness in prefrontal regions (even when age and gender controlled)
neuroticism negatively correlated with cortical thickness in the orbitofrontal cortex (not significant after controlling for gender)
what do functional brain measures do?
measure and analyse the functional properties of the brain
who used fMRI to look at BAS scores and brain activation?
Barros-Loscertales et al (2010)
how did Barros-Loscertales et al investigate BAS scores and brain activation?
used fMRI
used a letter discrimination task- letters put onto a background image which is neutral, appetitive or aversive, asked if the letter is a vowel or not
sensitivity to reward scale- measures individual differences to positive stimuli
what were the hypotheses for Barros-Loscertales?
appetitive pictures activated BAS related regions
regions known to modulate the action of the BAS correlate positively with SR scores
aversive pictures activate the BIS-FFFS structures
regions known to modulate the action of the BIS-FFFS correlate negatively with SR scores
what were the results for Barros-Loscertales?
appetitive picture condition activated regions within the limbic system related to the BAS
in some regions, activation positively correlated with SR scores
aversive picture condition activated regions within the limbic system related to BIS
activation in these regions did not correlate with SR scores
regions in the frontal lobes were activated during both the erotic and aversive picture conditions
