Studies of IQ correlations between twins and other relatives show that the average correlation for
A) identical and fraternal twins decreases into adulthood.
B) fraternal twins living together is stronger than the average correlation for identical twins living apart.
C) twin and nontwin siblings living together is stronger than the average correlation for those living apart.
D) fraternal twins living apart is stronger than the average correlation for nontwin siblings living together.

Question

Quizplus · Accepted Answer

Studies have shown that the average IQ correlation between twin and nontwin siblings is higher when they are raised together compared to when they are raised apart. This suggests that environmental factors play a significant role in shaping IQ, as siblings raised in the same environment are likely to have similar experiences and opportunities that contribute to their cognitive development. The average correlation for identical twins living apart and fraternal twins living together is actually stronger than the average correlation for fraternal twins living apart, indicating that genetic factors also play a role in IQ. However, the strongest correlation is still found between siblings raised together.

Studies of IQ Correlations Between Twins and Other Relatives Show