Chapter 7 – The Neuroscience of Personality Behavior and Physiology- Previously it was thought that our physiology (biological functioning) could not be affected by behavioro New research studying meditation (mindfulness) suggests our behavior can change our physiology o Davidson et al. randomly assigned people to meditation group or control group  Results showed those in the meditation group demonstrated less anxiety  Also showed greater brain activation on the left prefrontal cortex both at rest and when responding to positive and negative events (left is thought to be more involved in establishing positive emotions vs. right more involved in negative emotions)- Depressed people have trouble setting goals to achieve reward and trouble believing goals are possible Also showed better immune system functioning The Nervous System - Sympathetic – fight or flight, allows us to mobilize – turns off what we don’t need, turn on things we do need- Parasympathetic – allows body to come back down after arousal – turns everything on Brain Structure and Activity - Brain structure can be looked at via CT (x-rays) or MRI (radio frequency waves)o These tests only capture static pictures of the brain – see what the brain looks like, can’t see how the brain is actually functioning- Brain activity can be looked at via EEG (electrodes placed on the scalp to measure electrical activity in the brain), can also use evoked potential (EP), where we measure activity in response to a specific stimuluso Also the PET scan (slightly radioactive glucose injected into the brain) – active regions of the brain use up more glucose - fMRI – brain activity is monitored over time by tracing blood oxygen levels in the brain (gives different color scans of the brain) – cellular level o Images can be taken while a person is engaged in some cognitive activity of viewing stimuli o Problems with fMRI in personality research – thoughts react within milliseconds vs. 2 seconds for blood flow, also expensive so small sample sizes, time of day, nervousness, and nonindependence error (selection bias) - Transcranial magnetic stimulation (TMS) – brief electrical current passes through a coil placed on the heado The magnetic field disrupts neuronal activity, sometimes impairing, sometimes enhancing  Has been used to treat depression, fibromyalgia Not sure how useful would be personality research  No the same as electroshock therapy, can’t feel it Biochemical Activity - Neurotransmitters – chemicals released by neurons to inhibit or excited the next neuron into action o Norepinephrine (noradrenaline) and epinephrine (adrenaline) – considered stress hormones as well o Dopamine – related to feelings of pleasure, helps regulate movement, learning, attention and rewardso Serotonin – involved with mood regulation, arousal, control of sleeping and eating, and pain regulation o MAO – monoamine oxidase, an enzyme that can regulate availability ofcertain neurotransmitters Neurological Theories of Personality - Although a large portion of our personality is inherited, there are still physiological differences that exist - So far, we have been unable to find consistent physiological differences that clearly relate to differences in personality characteristics- Generally, researchers have looked at temperament as a guide Temperament - Stable across life span - Expresses through general energy level- Present from early childhood- Determined by genetics - Changeable with maturation and experience - Similar in other species - Four basic aspects:o Activity  Vigorous motion (vs. passivity)o Emotionality  Easily aroused (vs. calm and stable)o Sociability  Approaches and enjoys others (vs. aloof)o Impulsivity  Aggressive and cold (vs. conscientious and friendly)- Zuckerman – 3 primary temperaments o Extraversion – positive emotion, reward sensitivity, social rewards, sociability, approach o Neuroticism – negative emotion, anxiety, punishment sensitivity, withdrawalo Impulsivity – psychoticism, lack of constraint, sensation/novelty seeking, lack of conscientiousness and agreeableness Eysenck’s Pen Model- Believed that differences in personality are genetic and biological o Evidence to support his view included: Cross-cultural universality in traits – this consistency suggests a strong biological component  There is tremendous consistency in traits over time, despite changing environments- Reponses and habits may change, traits do not  PEN all show moderate heritability Neurology of Extraversion Eysenck- Thought the main difference between introverts and extroverts was arousal (either arousal level or arousability) – to positive emotions/stimulio Introverts were thought to have an overaroused baseline, so are more likely to act more restrained and inhibited, seeking conditions that will not aggravate the overstimulation o Extraverts let in too little stimulation  Thus, they both seek to find their optimal level of arousal o Ascending reticular activating system (ARAS) – a pathway that transmits signals from the limbic system and hypothalamus to the cortex, processes the cerebral aspects of arousal and emotion  No difference in arousal level between extraverts and introverts, though signal difference in how they respond to moderate stimulation (so, arousability or sensory reactivity) Neurology of Extraversion - People’s noise preferences and performance outcomes depend on their optimal level of arousal as determined by their personality o Introverts and extroverts engaged in cognitive reasoning task (learning a rule) o Exposed to white noise – 3 conditions  1. Choice – select volume “right for you” 2. Assigned same – volume matched  3. Assigned different – volume was opposite - introverts showed greater arousal in 3; performance went down in that condition - Eysenck thought that N had to do with stability or instability of the sympathetic nervous system (extrasensitive emotional or drive system) o Extraversion is marked by positive arousal (excitement, energy) vs. negative arousal (fear and anxiety)o People high in N show increase in heart rate in response to intense stimuli, and greater startle response to fearful pics, so more sensitive to negative emotions, not just arousing situations Reinforcement Sensitivity Theory- RST – proposed by Jeffrey Gray – personality is the variation in the functioning of the brain o