In the past, a popular research question in social inequality research was whether our behavior is determined more by genes or by the environment – nurture versus nature. This question seems outdated today. Why?
RW: The question is outdated, because the question has been answered! No dimension of human behavior is determined solely by either genes or the environment independently. We know now from many years of work in behavioral, statistical, and human genetics that human behavior (whether it’s health behavior, sexual behavior, educational attainment, etc.) is the result of a complex interaction between both genes and the environment. There is no “nurture versus nature” — instead it’s “nurture and nature.”
What is exciting about behavioral genetic research from a social science perspective?
RW: The amount of measured data that is rapidly becoming available in behavioral genetics research allows scientists to begin to combine the theory of classical twin and family models with measured genetic data on millions of individuals. So, for us, the explosion of data and interest in behavioral genetics research makes this perhaps the most exciting times to be a behavioral genetics researcher.
What data do you use in your research on behavioral genetics?
RW: We began our careers focused on classical behavioral genetics research, using small samples of twins and family in which there were no measured genetic data. Today our work focuses mostly on enormous datasets of millions of individuals that include measured genetic data. Some of these datasets include the innovative UK Biobank sample, 23andMe, Biobank Japan, or forthcoming work with exciting resources like the Million Veteran Program or TOPMed.
Where do you see the challenges for social scientists working with such data?
RW: Many of the challenges come in lacking the computational and methodological training necessary to do excellent work in behavioral genetics. Working in the field requires a serious investment in rigorous, interdisciplinary training, which often means seeking out training that is lacking in one’s graduate career. As more social scientists enter this quickly growing but complex field, it is critical that we adopt the rigor and caution that is now routine in human genetics, especially when interpreting results
Felix, your research interest is focused on fertility. What influence do genes have on the increase in age at the birth of the first child in industrialized countries?
We find that some genes are indeed robustly associated with fertility behavior such as age at first birth both in men and women. Genetic variation can barely explain trends over a short historical period, because our genomes do not change so rapidly. What we find, however, is that genetic influences on age at first birth increased in most recent birth cohorts due to gene-environment interaction.
Robbee, you are doing research on smoking behavior. What are the effects of education campaigns on smoking in today’s society? What is the role of genes in this respect?
Knowledge of the harmful health consequences of smoking, often driven by education-based campaigns like the 1964 Surgeon General’s Report on smoking and health in the United States, likely had something to do with the negative correlation we’ve observed between increasing education and decreased smoking behavior over time, although the concrete causes of the educational disparities in smoking is still an open research question. In recent work, my colleagues and I also find that the locations in the genome that are highly associated with both education attainment and smoking have become bundled similarly over time. In other words, the genotypes that are positively associated with educational attainment have become more negatively associated with smoking behavior over time.
We thank Robbee and Felix for their interesting insights.
