Understanding the biological roots of intimate behavior is a complex undertaking that involves the integration of evolutionary biology, evolutionary psychology, neuroscience, anthropology and sociology. Evolutionary biology describes theories that explain the persistence of certain types of behavior in terms of presumed evolutionary pressures or advantages, focusing on the human mind. Evolutionary biologists assume that behavior that maximizes the presence of associated genes in the next generation is the behavior most likely to persist. In this paper, we take the growing insights that arise from the study of the biology of attachment to frame the emerging policy choices underlying the governance of adult relationships. We have chosen to focus on the idea of commitment because we see two developments operating in tandem: the biological understanding of attachment has been expanding exponentially at a time of reexamination of the importance of long-term family stability. We believe that putting the two together--integrating biological understandings with sociology - will lead to the conclusions that the tendency to form pair-bonds is a deeply ingrained part of the species, lifelong fidelity cannot be expected on a widespread basis absent substantial coercion, and long term partnership is a "compromise that children win." These conclusions, however, will always leave some questions unanswered so that they can do no more than frame the unfolding policy debates. The question of what policy choices work - and at what price - can never be answered by biology alone. A better understanding of the new scientific insights underscores the conclusion that the determination of what is "natural" produces complex and varied answers, and the most natural of human tendencies is the desire to reorder human society. Accordingly, in light of the developing understandings of human pair-bonds from both the biological and sociological perspectives, we suggest various strategies that support long-term commitment between adults.
Naomi Cahn & June Carbone, The Biological Basis of Commitment: Does One Size Fit All?, 25 San Diego L. Rev. 223 (2004).