.0Chapter 10 Outline
❖ Heritability of Personality Traits
❖ Extraversion-Introversion
❖ Evolutionary Personality Theor and Mate Selection
Heritability of Personality Traits
❖ People are born with intelligence that combines with environmental
influences to determine adult intelligence levels
❖ Psychological disorders are affected by the genes inherited
➢ People are born with a higher susceptibility to disorders than others
Separating Environmental from Genetic Influences
❖ Twin-Study Method
➢ Procedure for separating the role of genetics from the role of
environment
➢ Take advantage of Monozygotic (MZ) dizygotic (DZ) twins
➢ Researchers give personality trait measures to members of both
kinds of twins
➢ Generates correlation tables
❖ Identical twins not only share physical features but also have similar
personalities. Researchers attribute this similarity in part to genetic
influences although the extent of genetic influences on personality
continues to be debated
Twin-Study Research Diagram
Correlations from a Twin Study
, Correlations from Twins Raised Apart and Twins Raised Together
Interpreting the Heritability Findings
❖ Key assumptions made by researchers using twin-study method
➢ Twin pairs can be accurately identified as MZ or DZ twins
➢ MZ and DZ twins have equally similar environments
■ Identical twins may be treated more alike than are DZ twins
❖ Environmental influence on personality traits may not be for MZ twins'
interpretation of the twin-study findings
❖ Discrepancies between the results of twin studies and studies using other
methods are attributed to methodological issues
❖ Nonadditive effects
➢ Genetic influence on some personality traits may not be seen unless
a unique combination of more than one gene is inherited
Extraversion–Introversion
❖ Extraversion-introversion is the most obvious of the major personality
dimensions
❖ Extraversion is probably the first characteristic teachers, job interviewers,
and potential dates recognize
❖ First, we’ll connect individual differences in extraversion-introversion
❖ Second, we’ll look at research examining
The Heritability of Extraversion
❖ Extraverts have probably heard some of these: There’s more to life than
having fun all the time
❖ Heritability of Personality Traits
❖ Extraversion-Introversion
❖ Evolutionary Personality Theor and Mate Selection
Heritability of Personality Traits
❖ People are born with intelligence that combines with environmental
influences to determine adult intelligence levels
❖ Psychological disorders are affected by the genes inherited
➢ People are born with a higher susceptibility to disorders than others
Separating Environmental from Genetic Influences
❖ Twin-Study Method
➢ Procedure for separating the role of genetics from the role of
environment
➢ Take advantage of Monozygotic (MZ) dizygotic (DZ) twins
➢ Researchers give personality trait measures to members of both
kinds of twins
➢ Generates correlation tables
❖ Identical twins not only share physical features but also have similar
personalities. Researchers attribute this similarity in part to genetic
influences although the extent of genetic influences on personality
continues to be debated
Twin-Study Research Diagram
Correlations from a Twin Study
, Correlations from Twins Raised Apart and Twins Raised Together
Interpreting the Heritability Findings
❖ Key assumptions made by researchers using twin-study method
➢ Twin pairs can be accurately identified as MZ or DZ twins
➢ MZ and DZ twins have equally similar environments
■ Identical twins may be treated more alike than are DZ twins
❖ Environmental influence on personality traits may not be for MZ twins'
interpretation of the twin-study findings
❖ Discrepancies between the results of twin studies and studies using other
methods are attributed to methodological issues
❖ Nonadditive effects
➢ Genetic influence on some personality traits may not be seen unless
a unique combination of more than one gene is inherited
Extraversion–Introversion
❖ Extraversion-introversion is the most obvious of the major personality
dimensions
❖ Extraversion is probably the first characteristic teachers, job interviewers,
and potential dates recognize
❖ First, we’ll connect individual differences in extraversion-introversion
❖ Second, we’ll look at research examining
The Heritability of Extraversion
❖ Extraverts have probably heard some of these: There’s more to life than
having fun all the time
