David P. Rail, Director of the National Institute of Environmental Health Sciences and of the National Toxicology Program, once challenged an audience with the following question: Suppose that thalidomide, rather than inducing structural deformities, had instead depressed IQ scores by 10%; would we ever have suspected it of adverse effects?
The answer to that question is disquietingly obvious. Rall framed it to illustrate the problems now taunting the science of environmental toxicology. Absence of death and frank disease are too blunt to serve alone as evidence of safety. The community demands protection against the subtle, insidious, often delayed consequences of exposure to toxic environmental agents, consequences exemplified by behavioral disturbances. Behavioral toxicology is a discipline created by that concern. Although a young discipline—the first meeting was organized in 19721—it is exerting a widening influence. In the Toxic Substances Control Act of 1976, which mandates premarket toxicity evaluation of