Are We Hardwired? The Role of Genes in Human Behaviour.
For an immunologist and a biological chemist to write a book about human behavior and its presumed genetic underpinning for a lay audience is surely tempting fate, for this is nothing, if not a minefield of controversy. When the jacket commendations come from three of the world’s most committed behavior geneticists, it is enough to make critics of the field such as this reviewer approach very warily. The early chapters do little to allay suspicion. The dubious heritability statistic is presented as if universally accepted as meaningful, braced by one of those human interest sagas of twins reared apart who on meeting 40 years later discover they have called their pet dogs by the same name and smoke the same brand of cigarettes. Proteins are described as ‘made from information stored in the DNA in the form of genes’ (p27). It seems we are set for a bumpy ride.
The authors’ intentions are, however, more complex. They approach humans via an evolutionary route, beginning with the sensitivities shown by even single-celled organisms. Caenorhabditis elegans, a nematode whose genetics, neuroanatomical wiring, development and behaviour must have had more research hours devoted to it than almost any species, perhaps excluding Drosophila, warrants a chapter, as does Aplysia for learning and memory. We then get to the ‘real stuff’: human aggression, addiction, intelligence and sexual orientation, themes which have so absorbed more than a century of behaviour genetic research.
Through most of the text, Clark and Grunstein are scrupulous in their attempt to avoid ‘gene for’ discourse, but they find this balance hard to maintain whenever they move into popular mode. Even in their discussion of the animal behavior literature they are less critical of simplistic conclusions than someone closer to the research front would be, for example the recent popular book, Wild Minds: What animals really think, by the neuroscientist and psychologist Mark Hauser. This gets more problematic the closer they come to the human literature, with its reification of ‘homosexuality’ or ‘alcoholism’ as if these were relatively unproblematic categories. Well-meaning reform by nomenclature, for example when they replace ‘sex’ by ‘gender’ and ‘intelligence’ by ‘mental function’, doesn’t quite solve the problem.
A similar problem arises in the treatment of that old ‘gene versus environment’ chestnut. Although the authors regularly refer to the role of ‘the environment’ as a counter to an overemphasis on gene talk, they don’t try to unpick the multiple meanings and levels embraced within that portmanteau term; instead it retains its monolithic character (for contrast, see how the neuropsychiatrist Nancy Andreasen, in her book, Brave New Brain, handles the term). Surely, at a point in the history of our science when the very term ‘gene’ decomposes into varying strands of differentially spliced and edited DNA, it is time to distinguish between cellular and organismic environments, diet, personal, historical, class and gender developmental histories. Even the idea of ‘shared versus non-shared’ environment, such a prominent feature of behaviour genetics discourse, makes the manifestly over-simple assumption that the home environment is the same for each of two sibs, an assumption that a little self inspection of all of our personal family histories should serve to dismiss.
Are we Hardwired? finishes with a robust defence of ‘free will,’ available to us, according to the authors, by courtesy of our complex brains and the chaotic, non-deterministic nature of development. There follow a couple of appendices, one on genetic methods, and the other a brief history of the excesses of past eugenic thinking and its implications for the future uses of genetic knowledge. Both the authors’ conscious social liberalism and the attempt to spring the determinist gene/environment trap are welcome, and it seems churlish to quibble that their discussions are hardly likely to satisfy either a historian or a philosopher. But those of us, and I do not exclude myself, cannot help it if our proper ambitions to explore the implications of our science lay us open to such critics.