Abstract
Nature versus nurture, genes versus the environment, these are the polar opposites when accounting for human behavior. In her book Studying Human Behavior, Helen Longino, a philosopher at Stanford University, focuses on research programs on genetic and biological determinants of two social behaviors: aggression and sexual orientation. Her choice of behaviors is intentional, as both have drawn political attention, albeit for sharply contrasting reasons. On the one hand, critics of research programs on genetics and aggression have raised the possibility of racism because the research may lead some to conclude that racial disparities in crime are biological in origin. On the other hand, identification of a “gay gene” (that is, genetic foundations for sexual orientation) would buttress claims about the naturalness of homosexuality. The goal of her book is to provide an overview of major research programs in these areas, which includes quantitative behavioral genetics, molecular behavioral genetics, neurobiological approaches, gene-environmental interactions, and social-environmental alternatives, and then subject them to epistemological, ontological, and social analyses. The book was not written with sociologists in mind—the discipline makes a couple of brief appearances—but will be of interest to specialists in the areas of sexualities and criminology, sociobiology, and the sociology of science.
The book is divided into two parts. The first part is focused on the science—the empirical evidence for key research programs and their associated methods, scope, and assumptions; the second part is more philosophical, covering epistemological and ontological issues as well as examining the “social” impact of these research programs on the field. Chapter Two provides a good example of the former. Here, Longino focuses on quantitative behavioral genetics, which includes twin studies as well as related designs exploiting variation in genetic relatedness (e.g., sibling and adoption studies). For example, one set up is to compare concordance in behaviors between identical twins against fraternal twins and nontwin siblings, whereas another compares identical twins reared together against those reared apart. The objective in these studies is to parse the amount of variation attributable to genetic as opposed to environmental factors. In addition to discussing key studies in quantitative behavior genetics, Longino raises concomitant assumptions and methodological issues. This latter section of Chapter Two is quite helpful and will be of interest to many who have wondered about the limits and assumptions of biological approaches. In the case of quantitative behavioral genetics, sample selectivity is a major issue, but the approach also makes a strong assumption that the amount of variance attributed to genetic factors does not reflect unmeasured environmental factors. Studies of identical twins may also overstate genetic causes of behavior, since these individuals have identical genetic makeup, whereas that is not the case for everyone else.
Longino then replicates this basic scaffolding for each major approach: social-environmental approaches (Chapter Three), molecular behavioral genetics (Chapter Four), neuroscience (Chapter Five), and integrative approaches (Chapter Six). With regard to Chapter Four, exploiting advances associated with DNA sequencing, molecular behavioral genetics seeks to correlate specific DNA sequences or chromosome loci with behavior. Here, the issue is empirical; robust findings are scant. There are also similar methodological issues including omitted environmental variables and sample selectivity. By social-environmental approaches, Longino really means developmental psychology. Where the environment was not well specified in genetic approaches, the issue with developmental psychology is the omission of genetic factors in causal accounts. This seems more of an issue for small-scale studies in psychology, where shared genes are likely among siblings and parent-child dyads. This leads her to conclude, oddly, that genetic and social-environmental approaches have equivalent limited generalizability. It seems that representative samples of unrelated individuals are fairly immune to this criticism, but then again sociology is largely excluded from this monograph.
In Part Two, which presents epistemological and ontological issues, Longino brings the philosopher’s insight to bear. In Chapter Eight, she raises the possibility of integration as opposed to continuing monism among the varying genetic and social-environmental approaches. Here, she diagrams how each approach incorporates or ignores the genome, the intrauterine environment, physiology, the shared and nonshared environment, and demographic characteristics. This chapter is incredibly useful and informative. Nevertheless, she argues that integration is intractable, since each approach parses biology and the environment in different ways. Instead, she suggests that research on aggression and sexuality is by default competitive, where different approaches battle for supremacy, but that pluralism is possible and preferable.
Chapters Nine and Ten present ontological issues and the uptake of research programs in the literature, respectively. The former focuses primarily on defining and measuring aggression and sexuality. I found this to be a useful discussion as social scientists often rely on taken-for-granted notions of both aggression and sexuality. Yet the criticism of measurements of aggression and sexuality as being too heterogeneous, on the one hand, and overly reliant on the Kinsey scale, on the other, rang hollow. It may be the case that the research programs considered in this book suffer from definitional and measurement issues, but sociologists are likely more aware that their definitions and measurements are context specific. Chapter Ten, in contrast, examines citation patterns of these research programs and finds that most research programs are in silos, segregated from one another. This suggests that the possible pluralism of these programs does not currently exist. Of all the chapters this was the least useful, as there was little attention to whether a particular research program had an impact on the social sciences. That said, genetic research programs are of great interest to the general public. In the wake of highly acclaimed movies, such as Blade Runner and Gattaca, Longino does not speculate why there might be a substantial audience for research on genetics and behavior.
This book has numerous strengths, which I mentioned above, but it is worth noting two major issues. First, although Longino does review each research program’s literature, she generally does not focus too much on the strength of the empirical evidence. Research programs on genetics and behavior are controversial, and a key issue is whether a finding in a single, small-scale study is replicated. My understanding of the literature is that many genetic findings have not been replicated. Longino does mention this information, but greater clarity about the replicability of genetic findings could have been improved. Second, the narrow focus on developmental psychology as the relevant social-environmental alternative to genetic research programs is unfortunate. When accounting for aggression and sexuality, Longino concludes that there is a need to go beyond the individual by understanding these behaviors as being caused by population characteristics. Indeed, sociology, criminology, and sex research have much to contribute to that discussion.