Module 63 REVIEW

• 63-1 What evidence points to a genetic influence on intelligence, and what is heritability?

• Studies of twins, family members, and adoptees indicate a significant hereditary contribution to intelligence scores.
• Intelligence seems to be polygenetic, and researchers are searching for genes that exert an influence.
• Heritability is the proportion of variation among individuals that can be attributed to genes.

• 63-2 What does evidence reveal about environmental influences on intelligence?

• Studies of twins, family members, and adopted children provide evidence of environmental influences.
• Test scores of identical twins raised apart are slightly less similar (though still very highly correlated) than the scores of identical twins raised together.
• Studies of children raised in extremely impoverished environments with minimal social interaction indicate that life experiences can significantly influence intelligence test performance.
• No evidence supports the idea that normal, healthy children can be molded into geniuses by growing up in an exceptionally enriched environment.

Multiple-Choice Questions

1. Heritability relates to the
   1. percentage of a person’s intelligence that is due to environmental influences.
   2. percentage of a person’s intelligence that is due to genetics.
   3. correlation of intelligence test scores among family members.
   4. extent to which variability among individuals’ intelligence scores can be attributed to genetic variation.
   5. genetic stability of intelligence over time.
2. There is a greater correlation between the IQ scores of identical twins raised together than for fraternal twins raised together. What conclusion can be drawn from this data?
   1. There is no significant hereditary contribution to intelligence.
   2. There is no significant environmental contribution to intelligence.
   3. There is no significant genetic or environmental effect on intelligence.
   4. There is a genetic effect on intelligence.
   5. There is an environmental effect on intelligence.
3. Which of the following is true of the mental similarities between adoptive children and their adoptive parents over time?
   1. Adoptive children become much more similar to their adoptive parents over time.
   2. Adoptive children become slightly more similar to their adoptive parents over time.
   3. There is hardly any similarity when the adoptive children are young or when they are older.
   4. Adoptive children become slightly less similar to their adoptive parents over time.
   5. Adoptive children become much less similar to their adoptive parents over time.
4. According to Carol Dweck, students are often hampered by a “fixed mindset.” This means they believe:
   1. intelligence is biologically set and unchangeable.
   2. it is never good to change your mind once it is made up.
   3. intelligence is changeable.
   4. they have already done everything they can to improve.
   5. problems can only be solved in a particular way.

Practice FRQs

1. Explain whether each of the following comparisons demonstrates the influence of genetics or of environment on intelligence.
   • The correlation of intelligence test scores for identical twins raised together is about +.85. For identical twins raised apart, the correlation is about +.72.
   • The correlation of intelligence test scores for identical twins raised together is about +.85. For fraternal twins raised together, it is about +.60.

Answer

1 point: The first comparison demonstrates the influence of environment. The people being studied were genetically identical twins in both cases, so the higher correlation for identical twins raised together must be due to environment. Page 647

1 point: The second comparison demonstrates the influence of genetics. In both cases, the twins being studied were raised in the same environment, so the higher correlation for identical twins must be due to the fact that there is more genetic similarity between identical twins than between fraternal twins. Page 647

2. Explain two environmental interventions that can help children develop better cognitive skills.

(2 points)