What are biological models of personality?
Biological models explain stable personality traits by underlying biological systems such as brain structure and function, neurotransmitters, hormones, and genetic factors.
They assume personality has a biological basis that can be measured objectively.
Which approaches exist in biological personality research?
Top-down approaches start from traits and search for biological correlates (e.g., Big Five).
Bottom-up approaches start from brain systems and examine resulting behavioral tendencies (e.g., Gray’s RST).
What was Hippocrates’ temperament theory?
Hippocrates proposed four temperament types based on bodily humors: phlegmatic, sanguine, choleric, and melancholic.
There is no empirical or biological evidence supporting the idea that body humors determine personality traits.
What is phrenology?
Phrenology claimed that specific personality traits are localized in brain areas and reflected by skull shape.
Because skull shape does not reflect brain function and relationships between body type and personality are weak.
What was Hans Eysenck’s main contribution?
He developed a biologically grounded trait model using factor analysis
and criticized circular explanations in personality theory.
What are Eysenck’s three supertraits?
Extraversion–Introversion, Neuroticism, and Psychoticism.
What does Extraversion–Introversion reflect biologically?
Individual differences in baseline cortical arousal in response to environmental stimulation
Introverts are more easily cortically aroused, experience stimulation as aversive, and therefore avoid highly stimulating situations.
Extraverts have lower baseline cortical arousal and seek strong social or sensory stimulation to reach optimal arousal.
EEG, heart rate, sweat gland activity, noise and pain sensitivity correlate with extraversion, although fMRI findings are inconclusive.
What biological systems underlie Neuroticism?
The limbic system and autonomic nervous system (ANS), especially stress reactivity.
High Neuroticism: Fast, intense reactions to stress and slow recovery of autonomic arousal after threat.
What biological factors are linked to Psychoticism?
Higher testosterone levels and possible involvement of dopamine, especially related to aggression and antisocial behavior.
What is sensation seeking?
A personality trait describing the tendency to seek novel, complex, intense sensory experiences, even when involving risk.
They engage more often in risky behaviors (e.g., extreme sports, substance use) but may also choose high-risk professions.
How is dopamine related to sensation seeking?
What is the role of serotonin in sensation seeking?
High sensation seekers need stronger dopamine release to experience reward, leading them to seek intense stimulation.
Lower serotonin levels are associated with impulsivity, disinhibition, and aggression.
Which brain structures differ in sensation seekers?
Reduced prefrontal cortex control, increased reward sensitivity in the striatum and nucleus accumbens, and reduced amygdala reactivity.
What is the Alternative Five (Zuckerman)?
A personality model including
Sociability,
Activity,
Sensation Seeking,
Aggression–Hostility,
and Neuroticism.
What are DeYoung’s two meta-traits?
Plasticity and Stability.
What does Plasticity represent?
Adaptability,
exploration, and engagement with novelty;
shared variance of Extraversion and Openness;
linked to dopamine.
What does Stability represent?
Emotional regulation,
impulse control, and consistency;
shared variance of Conscientiousness, Agreeableness, and low Neuroticism;
linked to serotonin.
How are Big Five traits related to brain volume?
Extraversion → medial OFC (orbite frontal)
Conscientiousness → LPFC; (lateral prefrontal cortex)
Agreeableness → STS; (superior temporal Sulcus)
Neuroticism → reduced DMPFC (Dorso médial prefrontal cortex) and hippocampus.
What is the General Factor of Personality (GFP)?
A higher-order factor accounting for shared variance across all personality traits.
How much variance does GFP explain?
Approximately 30–50% of variance in personality measures.
What is a major criticism of the GFP?
It may reflect social desirability or response bias rather than a true biological trait.
What is the core idea of Reinforcement Sensitivity Theory?
Personality differences arise from individual sensitivity to reward, punishment, and conflict-processing systems.
different systems (gray)
What is the Behavioral Approach System (BAS)?
A system responding to appetitive stimuli,
driving approach behavior,
impulsivity, and positive affect;
linked to dopamine and basal ganglia.
What is the Fight–Flight–Freeze System (FFFS)?
A system responding to aversive stimuli with fear and panic reactions via fight, flight, or freeze responses.
What is the Behavioral Inhibition System (BIS)?
A system resolving conflicts between BAS and FFFS, regulating attention and arousal; associated with anxiety.
How are personality traits linked to emotions?
Neuroticism → negative emotions;
Extraversion → positive emotions;
Agreeableness → empathy and trust;
Openness → curiosity;
Conscientiousness → emotion regulation.
What is the role of dopamine in emotion and personality?
High dopamine is linked to positive emotion, energy, impulsivity, and reward sensitivity;
low dopamine to low energy and anxiety.
What is the role of serotonin in emotion and personality?
High serotonin is linked to mood stability and self-control;
low serotonin to depression, aggression, and impulsivity.
What is the role of cortisol?
Cortisol is involved in stress and threat responses.
What is testosterone associated with?
Dominance, competitiveness, aggression, and sexually dimorphic characteristics.
What is hemispheric dominance in emotion?
Individual differences in left versus right hemispheric activity related to emotional processing.
What is frontal asymmetry?
What is associated with left vs. right frontal asymmetry?
EEG-based comparison of left and right frontal cortex activity at rest to measure emotional tendencies.
Left → positive emotion and approach; Right → negative emotion and avoidance.
How does anger challenge the valence model?
Although anger is negative in valence, it is linked to left frontal asymmetry due to its approach motivation.
What is plasticity in biological personality models?
The idea that biological systems and personality traits change as a result of environmental influences.
-> Winning increases testosterone; leadership increases serotonin; juggling or taxi training changes brain anatomy.
What are strengths of biological personality models?
They allow causal testing, use objective measures, and provide insight into emotional and motivational processes.
What are limitations of biological personality models?
Reductionism, weak mapping between biology and traits, and limited research on higher-order cognition.
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