Week 6: Personality persepctives

Question 1

Riemann et al 1997 method and findings

Answer 1

twin study

compared 950 mz and dz twins on the big 5.

Mz correlations higher (notably double) than dz twins

Question 2

Falconer’s formula: Heritability estimate

Answer 2

h^2 = 2 (rmz - rdz)

rmz = correlation for mz twins

Question 3

Heritability estimate from studies in general

Answer 3

• Suggests personality is influenced by genetic factors
  About 20-50% varience due to genetics

Question 4

Adoption study: Loehlin et al 1985

Answer 4

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

Question 5

Adoption study: Hershberger et al 1995, mz twins

Answer 5

found that identical twins reared apart did NOT show lower correlations on extraversion & neuroticism than identical twins reared together – but did on openness

(so genetic importance for extraversion and neuroticism but not openness)

Question 6

Adoption studies: Bergeman et al 1993

Answer 6

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”

Question 7

Issues with heritability estimates

Answer 7

• genetic variation across a population (an average)
• additive assumption (i.e. if only 20-50% of personality varience is due to genes, does that mean 50-80% is environment? Not exactly)
• 3 different genetic actions, where variance is more complex (Huang & Mackay 2016)…

Question 8

There are 3 types of genetic actions and their respective genetic variance are difficult to partition (Huang & Mackay, 2016):

Answer 8

– 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 9

Biological: Eysenck’s biological model of personality

Answer 9

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

Biological: extraversion is linked to

Answer 10

• Eysenck proposes that extraversion is linked to the arousal circuit responding to incoming stimuli (known as reticulo-cortical circuit)
• According to Eysenck, while introverts have over-aroused circuits, extraverts have under-aroused circuits

Question 11

Biological: Neuroticism

Answer 11

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

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

Question 12

Support for Eysenck’s bio model: Green (1984) & Kehoe et al. (2012)

Answer 12

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, Kehoe et al. (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

Gray’s reinforcement sensitivity theory (RST)

Answer 13

Gray (1970) proposes personality based on the interaction between three basic systems in the brain:

Behavioural approach system (BAS)

Behavioural inhibition system (BIS)

Flight/flight/freeze system (FFFS)

Question 14

RST: Behavioural approach system (BAS)

Answer 14

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

Question 15

RST: Behavioural inhibition system (BIS)

Answer 15

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

Question 16

RST: Flight/flight/freeze system (FFFS)

Answer 16

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

Question 17

Relationship between Gray’s & Eysenck’s model

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 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 / anxious (punishment is more arousing than reward)
  • Likewise, extraverts are reward sensitive (hence impulsive)

Question 18

Cloninger’s psychobiological model

Answer 18

Cloninger et al. (1993) proposed a psychobiological model of personality that includes

four dimensions of temperament and

three dimensions 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

Question 19

Cloninger: Temperament

Answer 19

• The four dimensions of temperament are:
  – novelty seeking
  – harm avoidance (thought to be linked to serotonin)
  – 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

Cloninger: Character

Answer 20

• Characters are based on differences in self-concepts, which vary according to the extent to which a person identifies the self as:
  – an autonomous individual (independent)
  – an integral part of humanity
  – an integral part of the universe as a whole
  
  • These aspects correspond to the 3 dimensions of character:
    – self-directedness
    – Cooperativeness
    – self-transcendence

Question 21

Problems with psychobiological theories

Answer 21

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 

* It has been argued that these theories may have oversimplified biological processes potentially underlying personality

Question 22

Neural correlates of extraversion (findings for DeYoung et al’s fMRI)

Answer 22

found extraversion associated with neural activation in response to pleasant stimuli in dopaminergic neurons in the reward network

* 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 was also found to be 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

Question 23

Neuronal correlates of neuroticism

Answer 23

most frequently linked to neuroticism is the amygdala, which modulates attention and arouses the sympathetic nervous system in response to danger signal

* Neuroticism is also linked to the medial prefrontal cortex (mPFC) and the dorsolateral prefrontal cortex (dlPFC), both thought to downregulates 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 24

Neural correlates of agreeableness

Answer 24

• Much of the relevant neuroscience 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

Question 25

Neural correlates of openness

Answer 25

* Openness is linked to individual differences in dopamine function * According to DeYoung (2013) – extraversion is associated with encoding of stimulus value, and functional connectivity between dopaminergic neurons and the nucleus accumbens and caudate nucleus – openness is correlated with encoding of stimulus salience, and functional connectivity between dopaminergic neurons and dlPFC * In addition, Beaty et al. (2016) reported that openness is linked to the information processing in the default network * Default network is a set of brain regions that are more active during rest than various cognitive tasks, representing some kind of “underlying” neural activation * Typically deactivated/less activated in externally driven tasks * It is thought to be responsible for self-generate thoughts, internal goal-oriented tasks, thinking about the past, planning the future, etc.

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 * Associations seem to be associated with serotonin levels, but evidence inconclusive so far. * Rueter et al (2018) found conscientiousness was positively associated with functional connectivity in this goal priority network * Measured resting state fMRI (default network) * Activation in dlPFC, insula, and ACC significantly associated with conscientiousness and their functional connectivity in other areas of the goal priority network * Important for determining the priority of goals as one aspect of concientousness

Question 27

Evaluation of neural correlates of personality

Answer 27

* Increasing number of research findings on neural correlates / instantiations of personality in the brain However, * A lot of individual pieces of evidence * No integrative view on personality as hardwired in the brain

Question 28

3 laws of behavioural genetics: Turkheimer 2000

Answer 28

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 “The nature nurture debate is over. The bottom line is that everything is ‐ heritable.” (Turkheimer, 2000, p. 160)

Question 29

Nature via nurture

Answer 29

heritability accounts for between 20%-50% of variance in personality traits * Shared environment (e.g. being raised in the same family environment) accounts for at best a small portion of variance * It follows that much of the variance is unexplained by genes nor shared environment, and is hence attributed to non-shared environment * This includes the individuals’ peers and aspects of parenting not shared with siblings * Because individuals select and shape their environments, effects on developmental outcomes are easier to detect for genes than for environment

Question 30

Nature via nurture * Barlow (2020)

Answer 30

argued that genes affect the way we perceive and react to the social world

Question 31

Nature via nurture Kendler 1997

Answer 31

wins were asked about their social support; genes accounted for 43–75% of variance in reported social support, while shared environment showed small effects.

Question 32

niche building

Answer 32

genes partly “cause” environment through self selection: ‐ Individuals can choose to create and transform environments according to their preferences or needs

Question 33

Group socialisation (Harris, 1995)

Answer 33

non-shared environment * 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 belonging 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 34

Group processes that influence personality

Answer 34

Context-specific socialisation group socialisation transmission of culture between-groups contrasts within-group differentiation

Question 35

context-specific socialisation

Answer 35

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

Question 36

group socialisation

Answer 36

we are socialised by the social groups we identify with

Question 37

transmission of culture

Answer 37

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

Question 38

between-group contrasts

Answer 38

we behave in ways depart from the group we reject

Question 39

within-group differentiation

Answer 39

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

Question 40

culture: Hofstede's cultural dimensions

Answer 40

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 – the degree to which a person is integrated into groups – power distance – acceptance of economic and social inequality – uncertainty avoidance – the discomfort experienced in ambiguous or unstructured situations – masculinity-femininity – assertiveness (masculinity) versus nurture (femininity)

Question 41

Hofstede et al. (2010) added 2 additional dimensions later

Answer 41

– Long vs. short term orientation – focusing on the future vs. the present and past for one's efforts – Indulgence-restraint – gratification vs. control of basic human desires related to enjoying life * It is important to emphasize that these dimensions describe cultures and not individuals. Also, the original survey was on work attitude, so these dimension are often referred to as “organizational culture”.

Question 42

Culture dimensions and personality Triandis (2001)

Answer 42

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 43

Culture dimensions and self-construals

Answer 43

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 emphasise relationship harmony * Relationship harmony can be seen as the functional equivalence of selfesteem in contributing to subjective well-being (Kwan et al., 1997)

Question 44

individualist culture wellbeing

Answer 44

independent self-construal self esteem = wellbeing

Question 45

collectivist culture well-being

Answer 45

interdependent self-construal relationship harmony = wellbeing

Question 46

Jiang & Sui (2022): self-construals and cognitive processing

Answer 46

found to predict different ways of cognitive processing experimentally priming the interdependent self-construal led to a reduced self-bias effect (i.e., faster and more accurate processing of self-relevant stimuli) (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)

Question 47

summary

Answer 47

* Genes play an important role in – yet do not fully explain – personality * Personality has specific neural correlates (in terms of brain activations) * Environment can impact personality by turning on/off genes, while personality, under the influence of genes, determines an individual’s choice of and reactions to environment * Culture affects how the mind works, and hence personality and/or its manifestation