PSYC 4520 1st Edition Lecture 16Outline of Last Lecture I. Hans Eysenck’s Theory of PersonalityA. Who was Hans Eysenck?B. The structure of personalityC. Physiological differences: Stimulation sensitivity and behavioral activation/ inhibition systemsD. A biological basis for personalityII. Heritability of Personality TraitsA. Nature vs. nurtureB. Separating environmental from genetic influencesC. Twin-study methodD. Adoption-study methodE. Problems with genetic researchOutline of Current Lecture I. Extraversion-IntroversionA. The heritability of extraversionB. Extraversion and preferred arousal levelC. Extraversion and happinessII. Assessment: Brain Electrical Activity and Cerebral AsymmetryThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.A. Indicators of brain activityB. Measuring brain activityC. Cerebral asymmetryD. Individual differences in cerebral asymmetryIII. TemperamentA. What is temperament?B. Temperament and personality C. Inhibited and uninhibited childrenIV. Application: Children’s Temperaments and SchoolA. The association between a child’s temperament and school lifeB. Temperament and academic performanceC. The “goodness of fit” modelV. Evolutionary Personality PsychologyA. How natural selection worksB. Evolutionary personality psychologyC. Natural selection and psychological mechanismsCurrent LectureI. Extraversion-IntroversionA. The heritability of extraversioni. Researchers measured extraversion-introversion in 12,898 adult twin pairs in Sweden and 7,144 adult twin pairs in Finland (the samples are large and the participants are composed of nearly every available twin in the designated population). When the correlations for these DZ and MZ twins were compared, considerable evidence for a genetic component forextraversion-introversion was found. MZ twins were also more alike than DZ twins, indicating a genetic influence. ii. Researchers also compared MZ and DZ twins reared together along with 95 pairs of MZ twins and 220 pairs of DZ twins reared apart. Again, there was a strong correlation between the scores of MZ twins reared in separate environments. iii. Extraversion has one of the strongest genetic components of any personality variable. B. Extraversion and preferred arousal leveli. Imagine that there are 2 areas to study in the library: one is quiet and isolated, while the other is open to the rest of the library. Which area a person chooses depends on whether he or she is an extrovert/introvert. Researchers found that those in the open area were more extroverted, while those in the isolated area were more introverted.ii. In another study, extroverts and introverts worked on a word-memory task while listening to noise through earphones. Introverts set their earphones at much lower levels than extroverts did. In a twist, some introverts were forced to listen to loud noise and some extroverts to soft noise. Introverts performed worse when exposed to higher levels of stimulation, and extroverts performed worse when exposed to lower levels of stimulation.C. Extraversion and happinessi. Extroverts are generally happier than introverts for three main reasons.ii. The first reason is that extroverts socialize more: they have more friends whom they interact with more often, and social contact is closely tied to feelings of well-being.iii. The second reason is that extroverts are more sensitive to rewards or mayenjoy the pursuit of rewards more. They are much happier when receiving positive feedback than introverts are.iv. The third reason is that extroverts seek tasks that they think will make them happy. They find rewards in situations that introverts do not see.v. One problem for extroverts is that they are also more impulsive. They act without really thinking, and this can cause problems.II. Assessment: Brain Electrical Activity and Cerebral AsymmetryA. Indicators of brain activityi. When people engage in reflective thought, most look off to one side; some consistently glance to the right, others to the left. This difference may tell us about our tendency to experience happiness or sadness: the direction in which people look when thinking may be an indicator of brainactivity patterns associated with emotion.ii. All psychologists, from Freud to Allport, have at one point used physiological measures (e.g. heart rate) in their experiments.B. Measuring brain activityi. We use an electroencephalograph (EEG) to measure electrical activity in the brain. This is relatively easy and does not harm the individual. The EEG also lets researchers record brain activity in very quick intervals. ii. EEG data is described in terms of cycles/second, or waves. The alpha wave is particularly important; the lower the alpha wave activity, the more activation in that part of the brain.C. Cerebral asymmetryi. Research on alpha wave levels in the front regions of the cerebral hemisphere is useful in understanding individual differences in emotion. Researchers find that the anterior region of a person’s right cerebral hemisphere shows a different activity level than the anterior region of that person’s left cerebral hemisphere. This difference in right and left hemisphere activity is called cerebral asymmetry.ii. Different patterns of cerebral asymmetry are associated with differences in emotional experience. Higher activation in the left hemisphere is associated with positive moods, while higher activation in the right hemisphere is associated with negative moods.D. Individual differences in cerebral asymmetryi. Most people typically have higher activation in one hemisphere than in the other, but which hemisphere displays the higher activity level differs for everyone. Differences in cerebral asymmetry are stable over time.ii. In one study, participants were identified as having either higher left hemisphere or higher right hemisphere activity. They then watched films designed to elicit certain emotions (e.g. happiness/fear). People with a higher level of left hemisphere activity responded more to the positive mood films, while those with higher right hemisphere activity levels were more responsive to negative mood films. iii. Psychologists describe these differences in terms of approach and withdrawal tendencies. Left hemisphere activity is related to movement toward the source of the emotion, and right hemisphere activity is relatedto movement away. So, higher