Textbook Notes (362,734)
Canada (158,032)
Psychology (4,729)

6 Brain, evolution, and personality.pdf

3 Pages
Unlock Document

Western University
Psychology 2550A/B
David Vollick

Brain,evolution, and personality October-04-12 12:54 AM BRAIN-PERSONALITY LINKS - Genes do not directly influence behaviour - they influence behaviour through their effects in shaping our body, particularly in our brain, and the large number of specialized chemical components that regulate their functioning - Biological bases of extraversion-introversion - According to eysenck's theory, extraverts differ from introverts because of differences in their physiological level of arousal (LOA) in the brain ○ Heproposed that these differences are influenced by the ascending reticular activation system (ARAS) of the brain --> the system believed to regulate overall arousal in the cortex - Introverts - even smallamounts of stimulation can overstimulate them physiologically --> leads to distress and withdrawal in their behaviour - Extraverts - ARAS not easily stimulated --> leads them toseek activities that will increase the level of stimulation - Study: ○ Foundthat introverts (compared to extraverts) show greater changes in their brain wave activity in response tolow frequency tones, indicating theirlower threshold for stimulation to the CNS ○ While intro/extraverts dont differ in their level of brain activity at resting levels, they do differ in response to stimulation - Their differences influence their performance under diff arousal levels todo them well - Optimal level of arousal (OLA) - defined by Hebb as the arousal level that is most appropriate for doing a given task effectively and shows that too much ortoo little arousal undermines performance - Brain asymmetry and personality differences - Brain asymmetry - People differ consistently in the degree to which the right versus the left sides of their brains are activated - that difference is called brain asymmetry - Tostudy the diffs, use electroencephalograph (EEG) - Tocalculate diffs in the brains asymmetry, researchers subtract the level of EEG brain wave activity on the left side of the brain from the right side ○ Positivemeasure = higher activity on right side ○ Negative = higher activity on right - Stable individual dfferences found in the brains asymmetry in anterior (frontal) brain regions - The behaviouralinhibition and activation systems - One of these individual differences involves two neurological systems in the brain: ○ Behavioural inhibition system (BIS) - causes people to withdraw from certain undesirable stimuli or punishments (thus, it inhibits behaviour) - ex, hamlet  Useful for avoiding danger ○ Behavioural activation system (BAS) - directs individuals toward certain desirable gals or incentives (thus activates approach behaviour)  It facilitates approach behaviours in the search for possible gratifications and positive outcomes in the pursuit of goals - Brain asymmetry and emotional reactivity - People who had higher resting levels of activity in their left frontal area of the brain gave more positive responses to happy stimuli ○ They also showed higher levels of self-reported BAS sensitivity on questionnaires - Higher resting levels of activity in the right frontal area of the brain were indicative of more negative feelings in respons e to aversive stimuli,as well as higher levels of self-reported BIS sensitivity on the self-report measures of reactivity tothreats - "takingmother away" study - those who cried and were more upset also tended to be the ones who characteristically have more brain wave activity on theright than on the left side, even when they were measured during the resting stage - Individual differences in this type of emotional reactivity seem to be a stable quality already seen in the young child - INFOCUS 6.1 AN EARLY EFFORT: PHYSIQUE AND PERSONALITY? - Endomorphic (soft and round, overdeveloped digestive viscera) --> viscerotonic (relaxed, loves to eat, sociable) - Mesomorphic (muscular, rectangular, strong) --> somatotonic (energetic, assertive, courageous) - Ectomorphic (long, fragile, large brain and sensitive nervous system) --> cerebrotonic (restrained, fearful, introvertive, artistic) - BIS, BAS, and personality traits - Greater activity in the BAS seems to be more characteristic of extraverts - Greater activity in the BIS = introversion/anxiety and torelated measures of temperament beginning early in life - BAS - associated with dominance/sensation seeking and impulsivity - BIS - with conscientiousness/behavioural inhibition - People who are dominantly left side active in their brains experience pleasant, positive emotions more easily when positive s timuliare encountered - People who are dominantly right-side active are more ready to respond with negative emotional reactions and distress when they face threatening or unpleasant events - Insum ○ Individuals who are extremely reactive in the BIS tend to be especially sensitive to potential threat, punishment, and danger  Focus more on the potential negative outcomes rather than on the possible gains and rewards when considering alternative action possibilities ○ People who are highly reactive in the BAS are likely to show the opposite pattern - more responsive to incentives and possible positive outcomes - Summary and implications - Findings on the BAS and BIS and on brain asymmetry suggest that these are specific and distinct incentive and threat systems in the brain that are responsive, respectively, to environmental signals of reward and threat, and that are related to positive and negative mood - There are clear and meaningful specific links between peoples' characteristic brain activities and their characteristic emoti onal and behavioural reaction patterns to different types of positive and negative stimulation - It is noteworthy that brain systems such as BIS and BAS are linked to personality in context-specific ways that again reflect the importance of taking account of the relationship between the expression of personality and the characteristics of the stimulus situation - The distinctive dispositional pattern of people high in BIS activity takes the form: if threats-punishments are encountered, then inhibition, high anxiety distress, negative emotions - Probing the biology of neuroticism - Anxious emotional arousal and worry may reflect two separate neural networks in the brain ○ These netwrosk are in the left VS right hemispheres and in the frontal VS posterior regions - Psychconditions that have been grouped under the term "neuroticism" may actually consist of two distinct mechanisms - Sensation seeking: a trait with a specific biological basis? - Sensation seeking - why some people go parachuting/drive fast and others prefer tv and stuff - Measured with a sensation seeking scale (SSS) --> taps into four diff aspects: ○ Thrilland adventure seeking ○ Experience seeking ○ Disinhibition ○ Boredom susceptibility - If lack of stimulation, sensation seekers get restless and upset - If placed in close confinement with another person, those low in sensation seeking become more stressed (in their own reports an
More Less

Related notes for Psychology 2550A/B

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.