Our ancestors wandered far and wide, seeking something new, and these migrations had consequences for our genetic pools. I have seen several reports of an archeological find in China (https://www.nytimes.com/2018/07/11/science/hominins-tools-china.html. Check out the cliff the archeologists had to scale for this research) of tools estimated to be around 2 million years old. This means that one of our ancestral lines left Africa much earlier than previously thought and traveled 8,000 miles east. These are categorized as hominins, precursors to genus Homo, but still bipedal with a brain beginning to enlarge. Paleoanthropologists have found fossils in China of Homo erectus that are 1.6 million years old. Fossils of hominins in Africa date back to over 6 million years ago.
Repeated migrations over the aeons carried different genes to different populations. Consider the gene for lighter skin colors that spread in northern populations or the genes enabling lactose digestion that appeared in Europe that spread in a variegated manner. My favorite is a gene first identified in the Denisovans from central Russa that some migration carried to Himalayan populations; this gene helps form the special type of hemoglobin that enables better adaptation to life at high altitudes (see post 7/4/14). I have wondered if some of the peoples that escaped to live in the high Andes also had such a gene. I say ‘escaped’ because of a find of a small site from ancient times in the Andes where life would not have been easy because game and edible plants were sparse. (See post 10/27/14) Why live there? The best hypothesis would seem to be escape from another tribe whose aggression was unbounded. Anyway, our ancestors clearly wandered the land over many generations seeking opportunities and avoiding negative exigencies.
I have been reading some research by Shinobu Kitayama and colleagues that is quite interesting about the cultural differences between Asian and American peoples. These seem to be fairly well established by multiple lines of research with different samples and different methodologies. In brief people from Asian cultures see themselves and the world as more interdependent (Americans see it as more independent), focus more on context than on a lone figure, define the self in relation to social relatedness rather than individual achievement, seek to accommodate rather than to be an agent of social change, de-emphasize individual achievements by focusing on their own faults and attributing success to social connections, think holistically rather than linearly, etc. Looking at this list you can see that Americans are quite different culturally, thinking linearly, highlighting personal achievement, valuing competition and social friction a bit more, etc. Just to speculate a bit more based on some lectures on Eastern intellectual traditions by Grant Hardy, the Western endorsement of desert monotheism and the Eastern endorsement of ancestor worship along with values of social order and justice that are accompanied by a flexible notion of deity would seem to reflect our different cultural ways of thinking evident 2-3000 years ago. Dr. Hardy says Christian efforts to convert China failed when the Pope and the Dominicans condemned ancestor worship as idolatry. That turned out to be an unacceptable violation of cultural mores and did not fit with the Asian understanding of what a deity is, so they rejected missionary efforts (and then the British gunboats showed up).
Kitayama and colleagues have begun to study how acculturation leads to changes in the brain, so that different cultures lead to different brain organization, thus the cognitive differences noted above. These differences arise from genetics to developmental epigenetics and acculturation experiences early on life. This makes perfect sense. The question arises for me of how migrations have contributed to these differences and how once the differences were initiated the differences became self-sustaining. Many peoples have revered their ancestors; the Chinese have maintained that even in the face of Christian zealousness. Certainly part of the answer here is the lack of intermarriage and the protection of the gene pool through isolation.
Consider one final example cited by Kitayama. Some significant percentage of Americans has a gene allele that promotes increased impulsivity and risk taking; this may contribute to a higher incidence of ADHD (as well as substance abuse, etc.?). This allele is virtually unknown in the Chinese population. Should there be more intermarriage, that might change. Why do we have that allele, or how did our migration pattern contribute to its presence? That brings to mind an old joke told at psychology conferences years ago. A prominent ADHD researcher, in the effort to make fun of the image of Californians, speculated thusly: The Europeans who populated North America were rebellious, impulsive risk takers—who else would sail across the Atlantic in small ships on a perilous voyage? And then from that population the even bigger risk-takers, impulsive people migrated west, so that Californians represented a genetic ‘distillation’, as it were, of impulsivity. Ha-ha.
Jaak Panksepp in Affective Neurosciencedocuments quite clearly how our mammalian heritage includes a proclivity for exploring in our neural systems for seeking and anticipating. Like a good many traits we have accentuated I think humans have a rarefied impulse to go beyond; this involves some risk but the species that spread across the globe and then went to the moon can manage a good deal of risk. Humans do wander and seek. We intermarry and that contributes to the flow between gene pools. We don’t intermarry and otherwise conserve our cultural heritage. Asians are indeed different than Westerners. As a member of the latter group, I think we could learn a thing or two from the former, e.g., mindfulness, the greater value of interdependence, the importance of contextualized thinking, etc. But for now I will travel on.