In this section we have looked at various aspects of genetic inuences on behaviour. These are the key points.

● Dierent traits are inuenced by genetic inheritance to dierent degrees.

● The traditional way to estimate this inuence is through studies based on genetic similarity (twin, family and adoption studies).

● Using the example of intelligence, we have seen that these studies demonstrate additive inuence of genetics and environment. On the one hand, adoption into more enriched environments results in an increase in average IQ scores. On the other hand, IQ of adopted children correlates more strongly with that of their biological parents. This suggests that biological inuences add to environmental inuences.

● Another nding is that genetic heritability increases with age. Similarity between related individuals increases as they grow older. This suggests niche-picking: biological factors can inuence environmental factors.

● Environmental factors can inuence biological factors through the process of regulation of gene expression. Genes can be switched on and o in response to environmental inuences.

● We have therefore seen that there is a complex dynamic interaction between genetic and environmental factors, which makes the nature-nurture debate in its original form outdated.

Review the section and nd the supporting arguments and evidence for each of these key points.