For generations, the back and forth between whether nature or nurture is at the root of behavior expression has been fierce. In Matt Ridley’s book, The Agile Gene, he explains in depth how evolution is not a battle between nature and nurture, but instead how evolution is nature via nurture. In the long history of the human race, behaviors have shaped how our genetic code gets turned on and off. One of the most fascinating ways this happens is simply through the culture we make for ourselves. Culture surrounds and is a part of every human on earth, and it drives different behaviors out of people from different cultures. These differences are so much at times that our culture can cause genetic changes within our bodies.
The relatively new field of cultural neuroscience can shed insight into how our nature via nurture as Matt Ridley talks of in his book can influence our behaviors. A prominent example of how culture can shape our genetics is through looking at the sickle cell trait. Sickle cell is a disease in which red blood cells change from a normal flat disk to a more crescent shape due to the presence of abnormal hemoglobin, hemoglobin S, in the red blood cells. These misshapen cells cause problems in oxygen distribution around the body and can cause extreme pain.
All in all, through the process of natural selection, this trait has been generally worked out of human’s systems, but an interesting cultural change has created an increased prevalence in people of African descent. Though this can be a terrible trait to have, having the sickle cell trait has its benefits, allowing for resistance to the disease of malaria. There were 198 million cases of malaria worldwide, 500,000 resulting in deaths, with most deaths coming from the areas in Africa. Interesting enough, 1 in 13 African American babies are born with the sickle cell trait and are the highest demographic who develop the disease. It is interesting how, due to the differing environments of cultures, natural selection has brought out a trait that is, in general, very harmful to the human race as a whole, but beneficial to a select group of people.
With our behaviors often times driven by the culture we live in, I believe Ridley explains nature via nurture in a very succinct way. He says, “These genes are at the mercy of our behavior, not the other way around (pp. 181).” It is interesting how our experiences and behaviors can so dramatically shape the biology of humans. The sickle cell trait is not the only example of this, and a large discussion comes out of where culture came from in the first place. With culture comes the underlying idea that we, humans, are social creatures. Without being social, without the ability to communicate, culture cannot exist. As Ridley puts it, one cannot develop culture alone.
Therefore, during the development of culture, humans must have developed communication. And in this development, more complex and sophisticated forms of communication developed. As human’s social behaviors changed, their genetics changed along with them. The beginning of bipedalism has been thought to be linked to the development of speech, a trait unique to the human species. Therefore, it is clear that through the development of speech and thus culture, our genetics were forever altered. Though no one truly knows how speech began, it is clear that the beginning of this truly human behavior shaped our genetic future via nurture.
Ridley makes the argument that as we developed more and more culture, our brains became larger and larger to hold all of the new information humans have created. It is interesting how today we have developed technology that gives humans more exposure to culture than every before, through the internet. Given the current discussion on how vastly our behaviors and creation of culture can impact the human species, what impact will the Internet prove to have on the species given time? Will the unlimited exposure of culture continue to benefit humans by further increasing knowledge and brain development? Or will the mindless side of the Internet come to do more harm than good. This is an interesting point that doesn’t have a right or wrong answer. In the end I believe that, for better or for worse, the technological age will have a massive effect on our genetics. The effect could be through a massive culture boom that even further develops us, or takes humans a step back due to the mindlessness of much of the Internet.
In the end, the combination of both history and current events of how human behavior has directly changed human genes is a fascinating topic of discussion. What the future holds is yet to be seen.
Center for Disease Control and Prevention (2016). Malaria. http://www.nhlbi.nih.gov/health/health-topics/topics/sca/signs
Goldman, J. G. (2014). How human culture influences our genetics. http://www.bbc.com/future/story/20140410-can-we-drive-our-own-evolution
National Heart, Lung, and Blood Institute (2015). Explore Sickle Cell Disease, http://www.nhlbi.nih.gov/health/health-topics/topics/sca
Ridley, M. (2004). The Agile Gene: How Nature Turns on Nurture. New York: Perennial/HarperCollins.