Paradoxical Ideas?

I am not a hardcore nativist, but I do tend to fall in line with genetic causes having primacy in determining behavior. I do have an issue with those who hold fast to the tabula rasa belief system. A person being born with a mind that is totally blank and ready for information seems to be fantasy at best.

The journal article I chose to enhance my argument had to do with epigenetics. The article was titled, Behavioral Epigenetics: How Nurture Shapes Nature, by Tabitha Powledge from the Journal of BioScience.

Epigenetics has to do with the way nurture shapes nature. It is concerned with the molecular events that govern the way the environment regulates the genomes of organisms (Powledge, 2011). The article suggested that being able to manipulate DNA and histone interaction, within the context of the hippocampus; it might be possible to change things from someone’s appearance, physiology, cognition, and behavior. Basically, how to trans-mutate experiences into changes in body function and behavior. In particular this study and the study of epigenetics in general, are concerned with the early development stages of life. This study, in particular, is concerned with behavioral epigenetics; the study of how signals from the environment trigger molecular biological changes that modify what goes on in brain cells (Powledge, 2011).

The basic premise is that the basis of behavior is learning and memory and how studies have shown that modifications made to specific genes can have measurable affects on learning and remembering. They show how DNA methylation and histone modifications are essential for learning and remembering, and how inhibiting their effects can eliminate conditioned responses to learned behavior. Conversely, blocking deacetylation can actually intensify or strengthen a memory in reference to a conditioned response.

The secondary premise of the article is that research has shown a connection between social experiences and how they can actually cause genetic changes. What is more interesting is that those changes can persist across generations.

Through the study they determined that by studying male mice, they could eliminate many confounds, and reach a somewhat more reliable consistency. When they introduced alcohol into the mice prior to mating, the offspring had more difficulty with spatial tasks, they were more aggressive, and they took more risks, and displayed more anxiety type behavior. When they introduced cocaine prior to mating, the outcome was smaller brains, attention deficits, and poor working memory. This was backed up by a study of people from northern Sweden. In this study they found that the risks of diabetes, cardiovascular disease, and early death is linked generationally in men (but not women) with grandfathers who had plenty of food available prior to puberty. The downside of epigenetics is that human research will be limited because human tissue is tough to come by, especially living brain tissue.

What does all of this mean?

For me, it would suggest that genetics continues to play a primary role in determining behavior. However, through genetic manipulation, whether achieved through medicine, diets, drug abuse, or during gestation behavior can be modified. I continue to remain resolute in genetic based behavior with some room for environmental manipulation.

With the “facts” surrounding both camps, the discussion of nature vs. nurture has somewhat shifted from an either/or to a discussion of how much of each.

Still,

Francis Galton offered a great question when discussing nature vs. nurture. I will restate it here:

Given that heredity and environment both influence the person we become, which is more important? Why?

Powledge, T. (2011). Behavioral Epigenetics: How Nurture Shapes Nature. BioScience , LXI (8), 588-592.