A good place to explore the interaction of biology and culture and potential mismatches is the human life course. If we consider how a human develops from an embryo into an adult and examine the forces that operate on that process, we will have a better perspective of how both biology and culture influence our lives and how our evolutionary history creates opportunities and sets limitations.
Of course, cultural factors interact with genetically based biological characteristics to widely varying degrees; these variable interactions influence how characteristics are expressed in individuals. Some genetically based characteristics will be exhibited no matter what the cultural context of a person’s life happens to be. If a woman inherits two alleles for albinism, for example, she will be deficient in the production of the pigment melanin, resulting in light-colored skin, hair, and eyes. This phenotype will emerge regardless of the woman’s cultural environment. Likewise, the sex-linked trait for hemophilia will be exhibited by all males who inherit it no matter where they live.
Other characteristics—such as intelligence, body shape, and growth— reflect the interaction of environment and genes. We know, for example, that each of us is born with a genetic makeup that influences the maximum stature we can achieve in adulthood. But to reach that maximum stature, we must be properly nourished during growth (including during fetal development), and we must avoid many childhood diseases and other stresses that inhibit growth. What factors determine whether we are well fed and receive good medical care? In the United States, socioeconomic status is probably the primary factor that determines nutrition and health. Socioeconomic status is thus an example of a cultural factor that affects growth. But in another culture, diet and health status might be influenced by whether the individual is male or female. In some cultures, males receive the best care in infancy and childhood and are thus often larger and healthier as adults than are females (Fig. 16-2). If there’s a cultural value on slimness in women, young girls may try to restrict their food intake in ways that affect their growth; but if the culture values plumpness, the effect on diet in adolescence will likely be different. These are all examples of how cultural values affect growth and development.