Presentation on theme: "The Biological Tradition Examples from lecture on history: The 4 humors (Melancholic, Sanguine) Phrenology Body Types."— Presentation transcript:
The Biological Tradition Examples from lecture on history: The 4 humors (Melancholic, Sanguine) Phrenology Body Types
The Biological Tradition Phineas Gage (1823-1860)
Temperament Individual differences in general mood or quality of emotional response that are moderately stable, inherited, and biologically based
Inhibited versus Uninhibited Children (Kagan, 1994) Inhibited –Reacts to unfamiliar people and situations with avoidance, distress, restraint –Takes longer time to relax in new situations –Has more fears and phobias –Is timid and cautious Uninhibited –Reacts to unfamiliar situations with spontaneity and joy –Takes shorter time to relax in new situations –Has fewer fears and phobias –Is not restrained in new situations
Kagan, Arcus, & Snidman (1993) At 4-months, –Videotaped behavior during familiar and novel stimuli (voices, mobiles, balloons) –Rated infants on reactivity (body movement, crying) At 14-months, 21-months, 4.5 years, 8 years –Videotaped behavior and monitored physiology
High vs. Low Reactive Infants (Kagan et al., 1993) High reactive –Show greater fearful behavior, heart rate acceleration, increased blood pressure –Smiled and talked less with unfamiliar adult –Were shy with unfamiliar peer –Varied within group Low reactive –Showed lesser fearful behavior, heart rate acceleration, increased blood pressure –Smiled and talked more with unfamiliar adult –Were less shy with unfamiliar peer –Varied within group
HEMISPHERE ACTIVATION Left Hemisphere Approach-related emotion Arousal -> happiness, resilience in the face of stress Underarousal -> vulnerable to sadness and depression Right Hemisphere Withdrawal-related emotion Arousal -> fear, disgust, anxiety Underarousal -> relaxation
HEMISPHERE ACTIVATION Davidson’s Evidence from EEG Reliable from one month to another (r =.66) More right-sided activation and more intense negative and less intense positive trait mood More right-sided activation and more intense negative affect in response to film clips meant to elicit fear and disgust Infants who cried when separated from their mothers had higher right-sided activation Inhibited toddlers had low left-sided activation People with greater left-sided activation had more natural killer cell activity
Behavioral Genetics Different ways of estimating genetic influence: Experimental animal studies Twin studies Adoption studies
Heritability Twin studies: Compare identical twins reared together with those reared apart Assume the similarity between “Together” twins due to shared genes and environment Assume the similarity between “Apart” twins due only to genes THEN: “Similarity of together” - “Similarity of Apart” = environment, and 1- environment = genes
Heritability Another form of twin study: Compare monozygotic (MZ) together twins with dyzygotic (DZ) together twins Assume similarity of MZ due to genes and environment Assume similarity of DZ due to 1/2 genes and environment
HERITABILITY Environment Genes Environment Example: Cloned people reared in very different situations Example: Identical twins, different pairs have very similar backgrounds Genes Environment Why is “gene” only circle impossible?? Example: Identical twins, different pairs have fairly different backgrounds 30% 60% 0%
HERITABILITY IS NOT The chance that an individual will have a certain characteristic How much influence genes or environment have on an individual person The absolute influence of a gene outside the particular environment in which the estimate was made
Heritability is: an estimate of the percentage of the variance in a particular characteristic in a particular study that resulted from genetic variation in that study.
HERITABILITY Some results from the major twin studies: Intelligence – H = 30% - 70% (some specific cognitive abilities are more heritable than others) Activity level, emotional reactivity, sociability-shyness – H = 20% - 50% Neuroticism, extraversion, impulsivity, monotony avoidance – H = 23% - 45% Depression – H = 13% for male relatives and 30% for female relatives Vocational interests – H =0.43 Religiosity – H =0.49 Traditionalism – H =0.53 Attitudes toward drinking alcohol – H = 51% Radicalism and toughmindedness – H > 50% Aggressive, antisocial, criminal behavior – H about 50%
Schizophrenia and Heritability Twin studies: 0% concordance in identical twins and 6% concordance in fraternal twins Adoption Studies: 1%3% 9%17% Not SS S Adopted Family Biological Family
THE “NATURE-NURTURE” DEBATE A devil, a born devil, on whose nature Nurture can never stick; on whom my pains Humanely taken, all, all lost, quite lost -The Tempest
NATURE AND NURTURE INTERACTIONS A Central Theme in Personality and Social Psychology The dynamic interaction between the person and the situation. People come into the world with some predispositions. They act in accordance with these predispositions and get reactions and feedback from the environment. These reactions and feedback, in turn, inform, drive, and even determine their behavior in the future. The cycle continues.
NATURE AND NURTURE INTERACTIONS Diathesis-Stress Model Examples Schizophrenia (genetic diathesis) Phobias (environmental diathesis) Alcoholism (possible genetic/environmental) Depression (possible genetic/environmental) Stress Level Time Critical Point Patient Becomes Ill
NATURE AND NURTURE INTERACTIONS Continuity of Behavior: Two Hypotheses (Caspi, Bem, & Elder, 1987) The data on children who tantrum: Men: downward occupational mobility, erratic work lives, more likely to divorce Women: married men with lower occupational status, more likely to divorce, ill-tempered mothers
NATURE AND NURTURE INTERACTIONS Continuity of Behavior: Two Hypotheses Cumulative continuity –We make certain choices, deliberate or not deliberate, that determine what direction our life goes Interactional continuity –Early temperament forms an interactional style that evokes reciprocal, maintaining responses from others. The person acts, the environment reacts, and the person reacts back.
MAIN POINTS Personality comes from a complex dynamic interaction of nature and nurture Nature contributes to personality through genetics, as well as basic processes such as brain activation, temperment, neuroanatomy, and biochemistry. Nurture contributes to personality through influences such as parental relationship, sibling competition, environmental stimulation, and culture. Nature and nurture interact from the fetus throughout the life span. Diathesis, cumulative continuity, and interactional continuity are some of the mechanisms through which these interactions occur.