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, not the situation

Eysenck’s Biological Model of Personality and Arousal

developed PEN model for personality dimensions. 

personality traits hierarchal → basic traits give rise to array of superficial traits.

genetically determined differences e.g. higher physiological arousal → conditioned by environmental stimuli more easily.

Ascending Reticular Activating System (ARAS)

balances excitatory and inhibitory mechanisms of individual differences. involves thalamus (nerve impulses), hypothalamus (metabolic, autonomic processes), cortex (neural processing).

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

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

Eysenck’s Biological Basis

• extraversion linked to lower baseline cortical arousal via ARAS (introverts higher baseline)

• neuroticism reflects limbic system sensitivity

• psychoticism associated w/ dopaminergic function + testosterone levels

• genetic heritability studies - ~40-60% variance in PEN traits bio. based

Eysenck - Supporting Evidence

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

Johnson et al. (1999) - PET - introvert frontal lobes more active than extroverts. Li et al. (2019) - EEG and fMRI higher cortical activation.

Lo et al. (2021) - twin studies affirm heritability for Ext and Neu.

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

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

personality based on tri-system interaction:-

• behavioural approach system (BAS) → approach behaviour to stimuli

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

• behavioural inhibition system (BIS) → avoidance behaviour to stimuli/threats

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

• fight/flight/freeze system (FFFS) → activated for immediate threats

  • amygdala + periaqueductal gray regulate immediate fear responses

BAS/BIS System

BIS = prefrontal ventral stream. activated by neg. stimuli. response aversive/avoidant. more responsive to punishment cues (Gable et al., 2000).

BAS = prefrontal dorsal system. responds to incentives. potential reward encourages approach. associated with impulsivity and hope (Gable et al., 2000).

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’/’Criticism or scolding hurts me quite a bit’

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 DImensions (genetically determined traits):

• novelty-seeking (40 items)

• harm avoidance (35 items)

• reward dependence (24 items)

• persistence (8 items)

3 Character Dimensions (learning-affected traits):

• self-directedness (44 items)

• cooperativeness (42 items)

• self-transcendence (33 items)

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, impulsiveness vs reflection

Harm avoidance = anticipatory worry vs optimism, fear of uncertainty vs confidence

Reward dependence = sentimentality vs insensitivity, attachment vs detachment

Persistence = single scale

Self-directedness = responsibility vs blaming, resourcefulness vs apathy

Cooperativeness = social acceptance vs intolerance, empathy vs social disinterest

Self-transcendence = self-forgetful vs self-conscious, spiritual acceptance vs materialism

Cloninger - Biological Nature

Miettunen et al. (2020) - neuroimaging show associations between neurotransmitters and temperament scales:

• novelty seeking → dopamine

• harm avoidance → serotonin

• reward dependence → noradrenaline

evidence temperament traits biologically rooted.

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.

Naylor et al. (2017) - high harm avoidance (pessimistic, need reassurance)/low self-directedness (low motivation, lack of adaptive coping) distinguishing feature of chronic pain sufferers.