Biological Theories of Personality

Lecture 7

Implicit Personality Theory

a person’s notions about which personality characteristics co-occur in people.

Fundamental Attribution Error

overestimate personality we observe in others. assumption that behaviour is a result of personality alone.

Eysenck’s Biological Model of Personality and Arousal

PEN model - personality dimensions. 

traits hierarchal → basic traits give rise to array of superficial traits (specific + habitual responses).

genetic and environmental differences influence personality formation. genetically determined differences e.g. higher physiological arousal → conditioned by environmental stimuli more easily.

Ascending Reticular Activating System (ARAS)

balance excitatory/inhibitory mechanisms of individual differences. involves thalamus, hypothalamus, cortex.

reticulo-cortical circuit = arousal to incoming stimuli (high = introvert)

reticulo-limbic circuit = arousal to emotional stimuli (high = neurotic)

Eysenck’s Biological Basis

genetic heritability studies = ~40-60% variance in PEN traits that are bio. based.
extraversion = lower ARAS baseline arousal.
introversion = higher ARAS baseline arousal.

Eysenck - Supporting Evidence

Corr et al. (1995) - high caffeine dose. introverts poorer performance on vigilance tasks (overstimulated). extroverts opposite.

Johnson et al. (1999) - PET - introvert frontal lobes more active than extroverts.

Prince et al. (2019) - N + E relate to first-onset anxiety, depressive disorders, agoraphobia.

Lo et al. (2021) - twin studies affirm heritability for E and N.

Gray’s Reinforcement Sensitivity Theory (1970; 1981; 1987)

• BAS → approach stimuli

  • dopaminergic pathways (ventral tegmental area → nucleus accumbens) drive reward-seeking

• BIS → avoid stimuli/threats

  • serotonergic + noradrenergic circuits in septo-hippocampal system mediate anxiety

• FFFS → immediate threats

  • amygdala + periaqueductal gray regulate immediate fear responses

BAS/BIS System (Gable et al., 2000)

BAS = prefrontal dorsal system. responds to incentives. potential reward encourages approach. associated with impulsivity.

BIS = prefrontal ventral stream. responds to neg. stimuli. response aversive/avoidant. more responsive to punishment cues.

Measurement of BIS/BAS - Scale (Carver & White, 1994)

5-point Likert Scale.

BAS Drive - ‘I go out of my way to get things I want’

BAS Fun Seeking - ‘I’m always willing to try something new if I think it will be fun’

BAS Reward Responsiveness - ‘When I’m doing well at something I love to keep at it’

BIS - ‘I feel pretty worried or upset when I think/know somebody is angry at me’

Gray’s RST - Supporting Evidence

Beck et al. (2019) - fMRI links BAS activity to ventral striatum activation in reward anticipation.

Perkins et al. (2020) - BIS activity links with amygdala + anterior cingulate activation during threat.

Corr & Cooper (2021) - meta-analysis confirms distinct neural correlates of BAS/BIS across tasks.

Cloninger’s Biological Model

4 Temperament Traits (genetically determined):

• novelty-seeking

• harm avoidance

• reward dependence

• persistence

3 Character Traits (learning-affected):

• self-directedness

• cooperativeness

• self-transcendence

Cloninger’s Model - Temperament and Character Inventory-Revised (TCI-R)

• 240 items (14 fillers)

• uses 5-point Likert scale

Item examples:

Novelty-seeking = excitability vs rigidity

Harm avoidance = anticipatory worry vs optimism

Reward dependence = attachment vs detachment

Persistence = single scale

Self-directedness = responsibility vs blaming

Cooperativeness = social acceptance vs intolerance

Self-transcendence = self-forgetful vs self-conscious

Cloninger - Biological Nature - Miettunen et al. (2020)

neuroimaging shows associations between neurotransmitters and temperament scales:

• novelty seeking → dopamine

• harm avoidance → serotonin

• reward dependence → noradrenaline

Cloninger - Supporting Evidence

Takeuchi et al. (2022) - genetic research supports TCI trait heritability + neurotransmitter system variation.

Moreira et al. (2020) - integrated configs of biopsychosocial systems for conditioning, intentionality and differences in personality underlie student engagement.