Read the following statements and choose the correct option: Assertion (A):…

In an Assertion-Reason item, the Assertion (A) and the Reason (R) are first judged true or false independently, and only then checked for whether (R) states the actual causal mechanism behind (A). In child development, the principle of individual differences holds that no two children develop at exactly the same pace; the standard explanatory framework for this variation is the interaction between heredity (genetic endowment) and environment/experience, often called nature-nurture interactionism.

Assertion (A) states that considerable variation exists in developmental rates among children -- this is a well-documented observation in child development. Reason (R) states that these differences arise from the complex interaction of genetic and experiential factors -- this is precisely the interactionist explanation developmental psychology offers for the variation described in (A). Because (R) supplies the actual mechanism producing the variation asserted in (A), both statements are true, and (R) is the correct explanation of (A).

This can be checked against each of the other combinations offered:

• "(A) is true, but (R) is false" does not hold, because the heredity-environment interaction account is itself an established explanation in child development, not an inaccurate claim.

• "Both (A) and (R) are true, but (R) is not the correct explanation of (A)" does not hold, because (R) is not a merely coincidental true fact standing beside (A); it directly states the mechanism that produces the variation described in (A).

• "Both (A) and (R) are false" does not hold, because both the observation of developmental variation among children and the heredity-environment interaction account are well established in developmental psychology.