50 Nature, Nurture, and the Disunity of Knowledge MICHAEL J. MEANEY Program for the Study of Behavior, Genes and Environment, Douglas Hospital Research Centre, McGill University, Montréal, Canada H4H 1R3 ABSTRACT: The Human Genome Project and the tools of modern molecular bi- ology bring enormous promise for the understanding of human biology. Juxta- posed, however, is a conceptual stagnation reflected in the continued nature/ nurture debate. More sophisticated models reflecting the inevitable inter- dependence of gene and environment are essential if we are to realize the po- tential offered by today’s technological advances. KEYWORDS: Nature vs. nurture; Gene–environment interactions; Human be- havioral gentics; Glucocorticoids; Socioeconomic factors and health Following a public lecture, a journalist approached the renowned psychologist Donald Hebb and asked for his opinion on which factor contributed more to the de- velopment of personality, nature or nurture. Hebb responded that to pose this ques- tion was akin to asking what contributed more to the area of a rectangle, the length or the width. Like all good urban myths, there are multiple versions of this story. The context changes somewhat, but Hebb’s quote remains intact in its piercing brilliance. Forty some years later, we pace about in the same state of confusion, asking the same foolish question, armed with the impressive tools of a new millennium, but without the wisdom of Hebb. NATURE VERSUS NURTURE 40 YEARS LATER Biomedical research is now positioned for an era of remarkable breakthroughs. The completion of the Human Genome Project, together with the availability of pro- tein and gene array technology, provides the potential for incredible advances in our understanding of the biological basis of development and the processes that lead to disease. Coupled with this astounding technical success, however, is a failure to de- velop conceptual models that traverse the chasm that lies between gene and function. The technology of 2001 is employed in the service of questions that have been con- ceptually unchanged since the 19th century. Our technical brilliance is constructed on a conceptual scaffolding that, in many areas of biology, is little changed from the 1920s. We risk leaving little more to the next generation than elaborate facades. Address for correspondence: Michael J. Meaney, Ph.D., Douglas Hospital Research Centre, 6875 Boul LaSalle, Montréal (Québec), Canada H4H 1R3. Voice: 514-761-6131 ext. 3938; fax: 514-762-3034. michael.meaney@mcgill.ca