Sociobiologists, sociologists and others have engaged in a prolonged discussion about the relationship between evolutionary adaptation and cultural adaptation. Evolutionary adaptation, as described first by Darwin, involves physical adaptations that are selected by the environment. Some scientists -- like the sociobiologists -- suggest that cultural adaptation can be ultimately traced to physical capacities in humans, like language, conceptual memory and manual dexterity. The adaptations of culture, they say, are selected by the environment in much the same way as physical characteristics. Many sociologists, on the other hand, say that cultural conditioning is not purely adaptive, and that there is creativity involved in cultural evolution. This is an old controversy called "nature versus nurture."
Most scientists now agree say that our physical attributes are no longer as important as the effects of culture on the individual. For example, our means of mobility has changed far more rapidly by motorized transport in the last century than it has by any anatomical adaptation in the human body.
Most scholars and researchers now agree with Harvard biologist Richard Lewontin that the nature-nurture controversy is a false choice between presumed opposites. He points out that culture changes the physical environment, which then has a formative effect on individuals and culture, which in turn adapts and creates new changes in the environment. This is called a dialectical relationship between nature and culture, and between culture and individuals, constructed of feedback loops between these categories.
This discussion is more complicated in modern times, as social disruptions like catastrophe, economic pressure, wars and other events combine with increased human mobility to mix cultures and expose individuals to different cultural influences. The internationalization of commerce has also had a homogenizing effect on many cultures. Coca-Cola and blue jeans, for example, have become nearly universal cultural artifacts. Economic pressure, in particular, has led to increased migration around the world, and those migrations have forced more individuals to adapt to new cultures.
Individuals who are transplanted into unfamiliar cultures face a variety of challenges. Foremost among those challenges can be language. Familial relationships, friendship rituals, ideas about authority, religious beliefs, music and food are among the phenomena that vary among cultures, and these are also those markers of individual identity that make people feel "at home." Stages of adaptation to a new culture are the honeymoon, when new things seem exciting; culture shock, when feelings of being overwhelmed, isolated, anxious and homesick take over; recovery, when acceptance begins to ameliorate homesickness; and adaptation, which seldom means complete assimilation into a new culture, but a level of comfort at being bi-cultural.