Physiological approaches to personality Flashcards
What is heritability?
The proportion of observed variation in a trait among individuals in a population that can be attributed to genetic differences.
What is environmentality?
The proportion of observed individual differences in a trait due to environmental influences.
What are the main behavioral genetic research methods?
Selective breeding, family studies, twin studies, and adoption studies.
What are shared environmental influences?
Environmental factors siblings share (e.g., same parents, home, schools).
What are nonshared environmental influences?
Unique experiences siblings do not share (e.g., different friends, hobbies).
Which has more influence on personality—shared or nonshared environment?
Nonshared environmental influences tend to be more significant for personality traits.
What is a genotype–environment interaction?
Different genotypes respond differently to the same environment (e.g., introverts vs. extraverts in noisy settings).
What are the three types of genotype–environment correlations?
Passive, reactive (evocative), and active.
What is the DRD4 gene associated with?
Novelty seeking, risk-taking, and sensation seeking.
What does molecular genetics study?
It identifies specific genes (or alleles) associated with personality traits.
What is heart rate variability (HRV)?
A measure of the variation in time between heartbeats; linked to stress and emotional regulation.
What is electrodermal activity (EDA)?
Skin conductance used to measure sympathetic nervous system activation (e.g., in neuroticism).
What personality trait is most associated with nonspecific electrodermal activity?
Neuroticism.
What is cardiac reactivity and what personality trait is it associated with?
Increases in blood pressure/heart rate under stress; linked to Type A personality.
What brain area is commonly affected in personality change from injury?
Prefrontal cortex.
What did the case of Phineas Gage show?
Damage to the frontal lobe can drastically alter personality, especially emotional control and social behavior.
What is the 2D:4D digit ratio, and what does it indicate?
Ratio of index to ring finger length; lower ratios linked to higher prenatal testosterone and traits like sensation seeking.
Which neurotransmitter is linked to extraversion and reward sensitivity?
Dopamine.
What personality traits are linked with stronger brain connectivity in the Human Connectome Project?
Openness (default mode network) and conscientiousness (executive control networks).
What did fMRI studies find about neuroticism?
Increased frontal brain activation when viewing negative images or anticipating aversive events.
Extraversion–Introversion (Eysenck)
Differences in baseline arousal regulated by the ARAS.
Introverts have higher cortical arousal → seek low-stimulation; extraverts have lower arousal → seek stimulation.
Optimal Arousal Theory (Hebb)
People seek a level of arousal that is ‘just right’ for task performance.
Under- or over-arousal leads to poor performance.
Arousability (Revised Eysenck Theory)
Extraverts and introverts differ in arousal response, not resting levels.
Introverts react more strongly to moderate stimulation.
Lemon Juice Test
Measures physiological arousability.
Introverts produce more saliva in response to lemon juice than extraverts.
