<p> Eysenck – Biological Basis of Personality</p><p>- fundamental personality characteristics are largely inherited - the central nervous system is the seat of personality functioning</p><p>- all behavior is learned</p><p>- studied possible relations between behavior and certain brain parts </p><p>Ascending Reticular Activating System (ARAS)</p><p>- a network of fibers extending from the spinal cord to the thalamus - stimulates the cortex - mediates states of arousal - involved in learning, conditioning, wakefulness and attention</p><p>- also has inhibiting effects: diminish cortical excitation - people differ in their basal levels of ARAS arousal - the same stimulus will be experienced as stronger or weaker, depending on one's basal level of ARAS arousal</p><p>Introversion – Extraversion</p><p>Introversion – higher level of ARAS arousal (lower ARAS thresholds) - easily become overstimulated - tend to be quiet, introspective, reserved - excitement decreases performance - distrust impulsive decisions - sensitivity to pain - "stimulus-shy"</p><p>Extraversion – lower level of ARAS arousal (higher ARAS thresholds)</p><p>1 - outgoing, has many friends - likes parties - craves excitement - impulsive - performance enhanced by excitement - tolerance for pain - "stimulus-hungry"</p><p>Limbic System (Visceral Brain) - related to emotional arousal - acts through the autonomic nervous system - activation of glands, muscles, heart rate, respiration, perspiration, etc. - people differ in activation thresholds</p><p>Neuroticism - lower threshold for activation of limbic system - greater responsivity of autonomic nervous system - overreact to even mild stimulation - emotionally labile - complain of worry and anxiety</p><p>It is possible to be intellectually aroused without emotional activation. It is impossible to be emotionally activated without simultaneous cortical arousal.</p><p>Neurotics may experience emotional arousal to stimuli that would be only cortically arousing to a normal individual. </p><p>How are Personality Characteristics Acquired?</p><p>- personality develops from genetic and environmental interactions</p><p>2 - dimensions of personality are inherited - behaviors are conditioned and/or learned - ease of conditioning depends on personality</p><p>- neurotic behavior is learned - involves a conditioned fear reaction - a neutral stimulus is paired with a physically or psychologically painful event - for someone genetically predisposed, only one such experience may be necessary - stimulus generalization occurs</p><p>- extroverts are not sensitive to stimulation - do not condition easily</p><p>"Biological causes act in such a way as to predispose an individual in certain ways to stimulation; this stimulation may or may not occur, depending on circumstances which are entirely under environmental control (Eysenck, 1967, p. 222).</p><p>Evaluation of Eysenck:</p><p>- Eysenck's model was designed to be tested in laboratory - support for the personality dimension findings - no direct empirical data for hypothesized links with brain functioning</p><p>Sample questions from the Eysenck Personality Questionnaire</p><p>1. Do you usually take the initiative in making new friends?</p><p>2. Does your mood often go up and down?</p><p>3 3. Are you mostly quiet when you are with other people?</p><p>4. Are your feelings easily hurt?</p><p>5. Can you easily get some life into a rather dull party?</p><p>6. Are you a worrier?</p><p>4</p>