THE EVOLUTIONARY ANTECEDENTS TO LOVE

Behaviors are adaptations to the physical, biotic, and social environments. Great diversity exists among vertebrates in reproductive behaviors and the neuroendocrine mechanisms underlying these behaviors. Study of this diversity illuminates species, population, and sex differences in hormone–brain-behavior relations. It also can provide insights into how and why certain neuroendocrine mechanisms evolved. Discoveries in evolution and ecology, neuroscience and endocrinology, are complementary and interrelated, and when applied in behavioral neuroscience, the investigator's perspective is less constrained by existing dogma. Naturally-occurring organisms not typically studied can be especially useful as their unusual adaptations illustrate alternative solutions to particular problems. Indeed, they ‘often force one to abandon standard methods and standard points of view’ with the result that, ‘in trying to comprehend their special and often unusual adaptation, one often serendipitously stumbles on new insights’ (Bartholomew, 1982). Thus, to ignore comparative research would greatly limit our understanding of the evolution of hormone-behavior relations. As Bullock (1984) admonishes, “without due consideration of the neural and behavioral correlates of differences between higher taxa and between closely related families, species, sexes, and stages, we cannot expect to understand our nervous systems or ourselves”. © 1998 Elsevier Science Ltd. All rights reserved.