Final answer:
Nonshared environmental variance refers to the unique experiences within a shared environment that affects children raised in the same home differently. Studies on identical twins raised apart and theories like the Range of Reaction highlight the impact of distinct environmental factors on individual development, resulting in variance within families and communities.
Step-by-step explanation:
The best definition of nonshared environmental variance is A) The aspects of the environment that children raised in the same home experience differently. This concept refers to the unique factors in the environment that affect individuals differently, even among those raised in the same family. It acknowledges that siblings can have different experiences and responses to their shared environment due to various factors, including personal interactions, different life events, and distinct relationships outside the home.
Studies of twins, especially identical twins raised apart, are valuable for disentangling the effects of genetics and environment on human development. Identical twins share the same genetics, providing a consistent basis for comparison. Differences that arise are therefore attributed to the nonshared environment since shared genetics are constant.
The Range of Reaction theory further illustrates the importance of nonshared environmental influences. Individuals may possess genetic predispositions, but the extent to which these predispositions are expressed depends on their particular environmental experiences. As such, even when children share some environmental aspects, they still undergo unique experiences that shape their development, thereby contributing to nonshared environmental variance within communities and families.