Lecture 6 - Personality: Genetic, neurobiological and socio-cultural perspectives

Question 1

Riemann et al., (1997) twin study on personality traits

Answer 1

Riemann et al. (1997) compared >1,000 monozygotic and dizygotic twins on the Big Five. Correlations between them were as follows:

MZ twins:
extraversion - 0.56
neuroticism - 0.53
agreeableness - 0.42
conscientiousness - 0.54
openness- 0.54

DZ twins:
extraversion - 0.28
neuroticism - 0.13
agreeableness - 0.19
conscientiousness - 0.18
openness- 0.35

higher correlations between MZ twins

Question 2

what is Flaconer’s formula used for?

Answer 2

to calculate heritability correlations

Question 3

Falconer’s formula to calculate heritability

Answer 3

h^2 = 2(r mz - r dz)

h = heritability
r mz and r dz are the correlations

Question 4

adoption studies on personality

Answer 4

Loehlin et al. (1985) found larger correlations between children and biological parents (.16–.34) than between children and adoptive parents (.02–.12) on a number of traits

• Hershberger et al. (1995) found that identical twins reared apart did NOT show lower correlations on extraversion & neuroticism than identical twins reared together – but did on openness
• Bergeman et al. (1993) concluded that genetic influence was “substantial” for openness (40%) and conscientiousness (29%), but was weak for agreeableness (12%) and that “there was little evidence of shared rearing environment”

(more similar in personality to biological parents rather than adoptive parents)

Question 5

issues with heritability estimates

Answer 5

• Heritability is concerned about genetic variation in a population
• The additive assumption in estimating heritability versus the effects of environment is problematic
• There are 3 types of genetic actions and their respective genetic
  variance are difficult to partition (Huang & Mackay, 2016):
  – Additive genetic actions – different genes work independently
  – Dominant genetic actions – dominant genes suppress expression of
  recessive genes
  – Epistatic genetic actions – certain genes determine whether other genes
  will be expressed or suppressed

Question 6

additive genetic actions

Answer 6

– Additive genetic actions – different genes work independently

Question 7

dominant genetic actions

Answer 7

– Dominant genetic actions – dominant genes suppress expression of
recessive genes

Question 8

epistatic genetic actions

Answer 8

– Epistatic genetic actions – certain genes determine whether other genes
will be expressed or suppressed

Question 9

Eysenck’s biological model of personality (explain)

Answer 9

Eysenck (1967) suggested that the human brain has two neural mechanisms:

– excitatory mechanism – keeps the individual alert, active and aroused
– inhibitory mechanism – causes inactivity and low energy

• These two mechanisms are regulated by two independent circuits of arousal

Question 10

what does Eysenck propose extraversion is linked to?

Answer 10

linked to the arousal circuit responding to incoming stimuli (known as reticulo-cortical circuit)

• According to Eysenck, while the introverts have over-aroused circuits, the extraverts have under-aroused circuits

(incoming circuits under-aroused so they are constantly seeking for more arousal extraverts (opposite for introverts)

Question 11

what does Eysenck propose neuroticism is linked to?

Answer 11

linked to the arousal circuit responding to emotional stimuli (known as reticulo-limbic circuit)

• In stressful situations, the neurotics would be more emotionally aroused while emotionally stable individuals are less aroused

(neurotics try to avoid further arousal)

Question 12

empirical support for Eysenck’s proposals on extraversion, neuroticism and arousal

Answer 12

• Geen (1984) asked introverts and extraverts to choose noise levels of music to listen to while doing a difficult and boring task
• As predicted, extraverts chose higher levels of music than did introverts. Both groups completed the task well under the chosen conditions, but not in the reverse conditions
• For neuroticism, in a neuroimaging study, Kehoeetal. (2012) found that the link between neuroticism and arousal is more complicated than Eysenck proposed
• While neuroticism is linked to increased reactivity to emotional arousal, it is also linked to reduced reactivity to positive stimuli

Question 13

Explain Gray’s reinforcement sensitivity theory (RST) (1970)

Answer 13

• personality based on interaction between 3 basic systems in brain
• behavioural approach system (BAS)
• behavioural inhibition system (BIS)
• fight/flight/freeze system (FFFS)

Question 14

what is the behavioural approach system (BAS) in Gray’s RST?

Answer 14

comprises motivations to approach and causes the individual to be sensitive to potential rewards and to seek those rewards

outgoing to seek rewards

Question 15

what is the behavioural inhibition system (BIS) in Gray’s RST?

Answer 15

comprises motivations to avoid based on conditioned sensitivity to potential punishment or non- rewarding stimuli

stay away from conditions

Question 16

what is the fight/flight/freeze system (FFFS) in Gray’s RST?

Answer 16

a mechanism that responds to threat by a tendency to fight, take flight or freeze

knowledge of NS

Question 17

relationship between Gray’s and Eysenck’s models

Answer 17

• Gray (1990) proposed that sensitivity to reward and punishment are two independent dimensions, and
• that Eysenck’s E and N dimensions should be rotated about 30° to form more causally efficient axes of ‘punishment sensitivity’ (anxiety) and ‘reward sensitivity’ (impulsivity)
• This theory explains why introverts are more aroused: they are punishment sensitive (punishment is more arousing than reward)
• Likewise, neurotics are punishment sensitive (hence aroused), at the same time reward sensitive (hence impulsive)

Question 18

Cloninger’s psychobiological model (1993)

Answer 18

• 4 dimensions of temperament and 3 dimension of character
• The temperament dimensions are independently heritable, manifest early in life, and involve individual differences in associative learning in response to novelty, danger or punishment, and reward;
• whereas the character dimensions mature in adulthood and influence personal and social effectiveness by insight learning about self-concepts

(picks up on Gray’s punishment and reward ideas. differentiated between temperament and character)

Question 19

4 temperaments in Cloninger’s psychobiological model of personality

Answer 19

novelty seeking
harm avoidance
reward dependence
persistence

Thought to be organised as independent brain systems, and linked to neurotransmitters that are responsible for the activation and inhibition of our behaviour and responses to rewards and punishments

Question 20

what are characters based on in Cloninger’s psychobiological model?

Answer 20

differences in self-concepts which vary according to the extent to which a person identifies the self as:
- an autonomous individual
- an integral part of humanity
- an integral part of the universe as a whole

Question 21

what are the 3 character dimensions in Cloninger’s psychobiological model?

Answer 21

self-directedness
cooperativeness
self-transcendence

Question 22

problems with psychobiological theories

Answer 22

• inadequate empirical support, with only some parts of the theories supported by research evidence
• For instance, the relation between neuroticism and arousal was much less well supported than that between extraversion and arousal
• Stewart et al. (2004) found that items measuring Cloninger’s traits more closely resemble FFM and Eysenck’s model than the original 7- factor model
• these theories may have oversimplified biological processes in their theory

Question 23

what have fMRI studies found about extraversion in terms of neural correlates?

Answer 23

• found extraversion associated with neural activation in response to pleasant stimuli in dopaminergic neurons and other brain regions in the reward network (right above brainstem)
• Effects of manipulating dopamine pharmacologically are moderated by extraversion, such that extraverts responded with more positive affect in response to stimuli previously paired with dopamine drug experience
• Extraversion positively related to volume of medial OFC (mOFC; a cortical region involved in monitoring the reward value of stimuli), as well as glucose metabolism in mOFC while at rest (to do with reward processing)

Question 24

neural correlates of neuroticism

Answer 24

• most frequently linked to neuroticism is the amygdala, which modulates attention and arouses the sympathetic nervous system in response to danger signal
• also linked to the medial prefrontal cortex (mPFC) and the dorsolateral prefrontal cortex (dlPFC), both thought to down-regulates negative emotions
• All of the systems implicated in neuroticism are modulated by serotonin, and pharmacologically modulating serotonin level was found to result in decline in neuroticism. However, the actual relationship between serotonin and neuroticism seems complex

Question 25

neural correlates of openness

Answer 25

• linked to individual differences in dopamine function
• Research has found that – whereas extraversion is associated with encoding of stimulus value, and functional connectivity between dopaminergic neurons and the nucleus accumbens and caudate nucleus – openness correlated with encoding of stimulus salience, and functional connectivity between dopaminergic neurons and dlPFC
• openness is linked to the default network, is a set of brain regions that are more active during rest and is thought to be responsible for self-generate thoughts (thinking and reflecting on oneself)

Question 26

neural correlates of conscientiousness

Answer 26

• Structural MRI studies have found positive associations of conscientiousness with the volume of regions in dlPFC
• It can be attributed to the fact that dlPFC is one of the regions of the goal priority network, which is thought to play a role in determining the priority of goals and reorienting attention away from distractors and toward goal-relevant stimuli
• And conscientiousness was positively associated with functional connectivity in this goal priority network
• Conscientiousness may be linked to serotonin, but extant evidence is inconclusive

Question 27

neural correlates of agreeableness

Answer 27

• research comes from the study of empathy, which involves mentalizing (understanding others’ perspectives) and mirroring (feeling others’ emotions)
• Mentalizing was found to primarily involve the default network, whereas mirroring for emotion primarily involves the insula and regions of midcingulate cortex.
• In an fMRI study, agreeable participants showed increased neural activities in the reward circuits knowing that a charity received a payment compared with that they received payment themselves
• Agreeableness is related negatively to testosterone, & positively with serotonin (higher levels of testosterone linked with lower levels of agreeableness but higher serotonin)

Question 28

criticisms of neural correlates of personality

Answer 28

• a lot of individual pieces of evidence
• no integrative view on personality as hardwired in the brain

Question 29

Turkheimer (2000) 3 laws of behaviour genetics

Answer 29

1. All human behavioral traits are heritable
2. The effect of being raised in the same family is smaller than the effect of
   genes
3. A substantial portion of the variation in human behavioural traits is not
   accounted for by the effects of genes or families

Question 30

heritability accounts for how much of the variance in personality traits?

Answer 30

between 20-50%

Question 31

how much variance does shared environment account for

Answer 31

at best a small portion

Question 32

much of the variance in heritability is attributed to what and why?

Answer 32

non-shared environment as much variance is unexplained by genes and shared environment

Question 33

idea of nature via nurture

Answer 33

• Barlow (2020) argued that genes affect the way we perceive and react to the social world
• In Kendler (1997), twins were asked about their social support; genes accounted for 43–75% of variance in reported social support, while shared environment showed small effects.
• In fact, genes partly “cause”environment through self-selection: Individuals can choose to create and transform environments according to their preferences or needs, known as niche building

(genes determine how we create our environment. identical twins created a more similar environment than non-identical twins)

Question 34

group socialisation theory (Harris, 1995) effect on personality

Answer 34

• With social categorisation, i.e., individuals have a tendency to place other individuals into social groups, being important
• An individual’s social identity is based on and derived from the groups one feels belong to and one’s perception of similarities and differences in relation to different social groups
• This theory attempts to explain what makes people similar as well as what makes people unique in personality

Question 35

group processes influencing personality

Answer 35

context-specific socialisation
group socialisation
transmission of culture
between-group contrasts
within-group differentiation

Question 36

context-specific socialisation

Answer 36

we learn from many sources and the learning is highly context-specific

Question 37

group socialisation

Answer 37

we are socialised by the social groups we identify with

Question 38

transmission of culture

Answer 38

culture is transmitted group-to-group, not merely parent to child

Question 39

between-group contrasts

Answer 39

we behave in ways depart from the group we reject

Question 40

within-group differentiation

Answer 40

while we imitate peer models, we also differentiate ourselves from our peers within-group

Question 41

hofstede’s cultural dimension (1980)

Answer 41

• Hofstede (1980) collected survey data on attitudes of employees of IBM, involving close to 117,000 cases from 71 countries
• Four relatively independent dimensions were identified:
  – individualism-collectivism
  – power distance
  – uncertainty avoidance
  – masculinity-femininity

Question 42

individualism-colelctivism dimension

Answer 42

degree to which a person is integrated into groups

(extent to which people feel independent)

Question 43

power distance dimension

Answer 43

acceptance of economic and social inequality

(power distribution)

Question 44

uncertainty avoidance dimension

Answer 44

the discomfort experienced in ambiguous or unstructured situations

Question 45

masculinity-femininity dimension

Answer 45

assertiveness (masculinity) vs nurture (femininity)

Question 46

what 2 further dimensions did Hofstede (2010) add?

Answer 46

long vs short term orientation
indulgence-restraint

Question 47

long vs short term dimension

Answer 47

focusing on the future vs the present and past for one’s efforts

Question 48

indulgence-restraint dimension

Answer 48

gratification vs control of basic human desires related to enjoying life

Question 49

what does organisational culture refer to?

Answer 49

the long vs short term orientation and the indulgence - restraint dimensions

Question 50

culture dimensions and personality

Answer 50

In a review, Triandis (2001) summarized that, comparatively, people in collectivist cultures are more likely to
– describe themselves as group members instead of as individuals
– emphasize collective goals
– pay more attention to external than internal determinants of social
behavior, and – be self-effacing

Question 51

link between culture dimensions and self-construals

Answer 51

• The links between cultures and psychosocial outcomes can be explained by independent versus interdependent self-construals (Markus & Kitayama, 1991)
• In particular, people in individualist cultures tend to construct a self as independent of others and emphasise self-esteem
• In contrasts, people in collectivist cultures tend to construct a self that is inter-connected to their social groups and emphasis relationship harmony
• Relationship harmony can be seen as the functional equivalence of self-esteem in contributing to subjective well-being (Kwan et al., 1997)

Question 52

relationship harmony diagram

Answer 52

individualist culture –> independent self-construal –> self esteem –> subjective wellbeing

collectivist culture –> interdependent self-construal –> relationship harmony –> subjective wellbeing

Question 53

study finding:

Independent versus interdependent self-construal has been found to predict different ways of cognitive processing

Answer 53

For instance, Jiang & Sui (2022) found that experimentally priming the interdependent self-construal led to a reduced self-bias effect (i.e., faster and more accurate processing of self-relevant stimuli)

• In another study (Zhang et al., 2017), priming independent self- construal caused Chinese participants to self-evaluate more favourably when faced with threatening feedback (without the same priming threatening feedback resulted in less favourable self-evaluation among Chinese participants than non-threatening feedback)