56 Abstracts

the proposition, the error characteristics of the learning device, and the proba-

bility that the proposition is true. A quantitative model shows how these three

considerations are related to each other.

Can Behavior Genetics Contribute to Evolutionary Studies of Behavior?

Michael Bailey Department of Psychology, Northwestern University, Evanston, Illinois

Most socially relevant individual differences studied so far appear to be

moderately heritable. These include dimensions of personality and intelligence

as well as complex behavior patterns such as religiosity, divorce, political

attitudes, and sexual orientation. Evolutionary behavioral scientists have cited

such findings primarily to establish the plausibility that ancestral populations

had sufficient additive genetic variation in relevant behaviors to allow an

adaptive response to natural selection. They have tended either to ignore

genetic variation in contemporary populations or to dismiss such variation as

“genetic noise”-variation without adaptive significance. Other possibilities

exist, including frequency-dependent selection.

This talk has three main goals: (1) to discuss the historical relationship

between behavioral genetics and evolutionary behavioral science; (2) to eluci-

date behavioral genetics methodology and evaluate some of the methodological

criticisms of it; and (3) to explore ways in which behavioral genetics might

contribute to evolutionary approaches.

Cognitive Adaptations for Threat, Cooperation, and War

John Tooby and Leda Cosmides Departments of Anthropology and Psychology, UC Santa Barbara, California

Increasing evidence supports the view that the human brain consists of a

diverse collection of complexly specialized information-processing adapta-

tions, including a series of cognitive adaptations that enable humans to engage

in social exchange and to understand threats. Situations of potential or actual

cooperative aggression constituted recurrent selection pressures that operated

during human evolutionary history, and more effective cooperators gained

resources denied to unallied individuals or less effective cooperators. We

suggest that humans (and a few other species) evolved an array of specialized

cognitive adaptations that make possible and regulate multi-individual cooper-

ative aggression. These circuits allow coalitions to coalesce, function, and

sustain themselves as groups of cooperating individuals. Although social

exchange and threat are necessary building blocks of human coalitional psy-

chology, we survey several additional design features of this zoologically

unusual cognitive competence, discuss obstacles to its evolution, and explore

reasons why its phylogenetic distribution is far rarer than the actual distribution

of ecological conditions that would favor it.