Exam 6: Genetic and Environmental Influences on Personality

Loehlin (1997)examined the effects of some aspects of the unique environment on personality,by investigating whether or not different experiences of two twins would tend to be associated with differences in personality.Which of the following accurately summarizes the results of Loehlin's study?

Which of the following results would indicate a high degree of similarity between mothers and daughters for a given trait (i.e. ,a high correlation between mother and daughter for this trait)?

Which of the following statements about similarity between relatives in personality can be considered accurate?

Recall the large-scale study of personality in identical and fraternal twins conducted in Germany .Which of the following best summarizes the results of that research with regard to additive genetic,non-additive genetic,and common environment influences on personality trait levels? (Consider the results based on self-reports or observer reports considered separately. )

Suppose that a researcher measures a trait in many pairs of identical twins and many pairs of fraternal twins.If the researcher finds that the correlation for identical twins on this trait was .60 and that the correlation for fraternal twins was .30,what would this tell us about the heritability of the trait? (Assume that all twins of the same pair were raised together.For the purpose of this question,accept all assumptions about the use of this twin design. )

In the question above,what would be the estimated effect of the common environment?

Suppose that a researcher wanted to estimate the similarity of personality trait for siblings raised together.Which of the following methods would allow the researcher to avoid the problem of "contrast effects" and "assimilation effects"?

Suppose that two sisters are raised by very strict parents.As a result of the parents' strictness,one of those sisters grows up to be very self-disciplined (i.e. ,more self-disciplined than she would have been if raised by other parents).Also as a result of the parents' strictness,the other sister grows up to be very undisciplined (i.e. ,more undisciplined than she would have been if raised by other parents).This situation is an example of which of the following?

Some researchers have suggested that adopting households might show less variability in many characteristics (e.g. ,parental warmth,parental strictness,parental education,etc. )than do households in general.If these characteristics really are less variable in adopting households,then what would this mean for estimates of common environment influences on traits?

Which of the following biological relatives is the proportion of shared genes not equal to 50% (or approximately 50%)? (Consider only the genes that are not shared by all persons. )

Suppose that the characteristic of height is found to be 75% heritable in a given population.What does this mean?

Suppose that a young boy has a genetic predisposition to be interested in music.While he is growing up,his parents notice these interests and encourage them by giving him musical instruments and enrolling him in music lessons.The boy then develops an even stronger interest in music than he would have had if he had not been exposed to this very musical environment.This situation is an example of which of the following?

Suppose that researchers estimate the unique environment influence on a trait by finding the proportion of variance that remains after genetic and common environment influences have been calculated.This estimate of unique environment influence could include which of the following sources? 1)Imperfections in the measurement of the trait 2)Random chance during development 3)Various specific features of the environment that differ within families

According to Sulloway's (1995)theory of birth order and personality,which of the following sets of characteristics would be expected to show higher levels,on average,among persons raised as later-born children than among persons raised as first-born children?

Consider the following examples of possible womb environment effects on psychological traits.In which of these cases can these effects be considered as influences of the common or shared environment? (Consider siblings who are not twins. ) 1)Some mothers consume a lot of protein during all of their pregnancies,and other mothers consume much less protein during all of their pregnancies 2)Some mothers experience more stress during their first pregnancy than during later pregnancies 3)Some mothers are exposed to fewer toxins during their first pregnancy than during later pregnancies.

Recall that Scarr and Carter-Saltzman (1979)examined the similarity of personality and other characteristics (a)for identical twins whose parents mistakenly believed them to be fraternal twins,and (b)for fraternal twins whose parents mistakenly believed them to be identical twins.What results did they obtain?

Which of the following would indicate the effect of the common (between-family)environment on a given trait?