Nature & Nurture Dr. Carolyn R. Fallahi

Nature-Nurture  Which is more important?  The Diathesis stress model  We figure out the relative amount of nature (genetics, biology, chemistry) & nurture (environment).  What about psychiatric disorders?  Which is more important?  The Diathesis stress model  We figure out the relative amount of nature (genetics, biology, chemistry) & nurture (environment).  What about psychiatric disorders?

Study Techniques  Twin Research  Identical versus fraternal twins (monozygotic versus dizygotic)  Shared environmental experiences  Common experiences, e.g. parent’s personality, intelligence, SES status, neighborhood live in, parenting techniques  Nonshared environmental experiences  Child’s own experiences within and outside the family that are not shared with siblings  Twin Research  Identical versus fraternal twins (monozygotic versus dizygotic)  Shared environmental experiences  Common experiences, e.g. parent’s personality, intelligence, SES status, neighborhood live in, parenting techniques  Nonshared environmental experiences  Child’s own experiences within and outside the family that are not shared with siblings

Epigenetic View  The interaction of heredity and environment.  Heredity directs the kind of environmental experiences a person has.  There is ongoing bidirectional interchange.  For example, the development of hearing and eyesight.  The interaction of heredity and environment.  Heredity directs the kind of environmental experiences a person has.  There is ongoing bidirectional interchange.  For example, the development of hearing and eyesight.

The study of Feral Children  Wild children who have been separated from society.  The Case of Genie.  Other cases.  Wild children who have been separated from society.  The Case of Genie.  Other cases.

Behavioral Genetic Studies  Intelligence: overall heritability of IQ scores is about.50 or 50% of the variance is explained.  Identical twins raised together:.86  Raised apart:.72  Fraternal twins:.60 &.52  Biological siblings:.47 &.24  Biological parent & child:.42 &.22  Adopted parent & adopted child:.19  Intelligence: overall heritability of IQ scores is about.50 or 50% of the variance is explained.  Identical twins raised together:.86  Raised apart:.72  Fraternal twins:.60 &.52  Biological siblings:.47 &.24  Biological parent & child:.42 &.22  Adopted parent & adopted child:.19

Temperament & Personality  Temperament: a set of tendencies to respond in predictable ways.  Buss & Plomin (1984) found.50 to.60 average correlations between temperatment scores of identical twins. The correlations for fraternal twins are about 0.  Temperament: a set of tendencies to respond in predictable ways.  Buss & Plomin (1984) found.50 to.60 average correlations between temperatment scores of identical twins. The correlations for fraternal twins are about 0.

Psychological Disorders  Schizophrenia: disturbances in logical thinking, emotional expression, social behavior.  Originally: thought due to a cold and inconsistent mother.  Now: concordance rates for identical twins: 48%; fraternal twins 17%.  1% of the general population has Schizophrenia.  Schizophrenia: disturbances in logical thinking, emotional expression, social behavior.  Originally: thought due to a cold and inconsistent mother.  Now: concordance rates for identical twins: 48%; fraternal twins 17%.  1% of the general population has Schizophrenia.