The focus of the research in this laboratory is the study of the biological bases of behavior. Experiments range from molecular endocrinology and behavioral neuroscience to descriptive ethology and behavioral ecology. All studies are designed to illustrate the manner in which the different levels of biological organization are integrated. Thus, any one study will utilize a number of techniques and methodologies.
Animal models are used to examine the functional outcomes and causal mechanisms of reproductive and social behaviors in vertebrates. This goal stems from my early interest as a social psychologist and social worker. After trying to study cooperative and agonistic behavior among Newark inner-city gang leaders in 1967 and 1968 (the years of the infamous summer riots), I switched to animal models because they tend to be simpler systems yet appear to operate on similar principles. This laboratory has, at one time or another, utilized a variety of species, including fruit flies, several fish, various amphibians, many reptiles, one bird, and three mammals. The bulk of the research, however, has focused on reptiles.
There are several reasons why I choose to concentrate on reptiles. First, reptiles occupy a central position in vertebrate evolution; both birds and mammals arose from reptilian ancestors. Behavioral and physiological processes known to be important in the regulation of mammalian behavior, including humans, are also found in reptiles. This suggests that such commonalities are fundamental to vertebrate reproduction. Thus, meaningful comparisons between reptiles and mammals allow us to test hypotheses regarding the evolution and adaptive significance of behavioral controlling mechanisms. Second, study of reptiles helps reveal the plasticity of these same mechanisms. Specific environmental constraints, when combined with physiological and phylogenetic constraints, shape reproduction and give rise to alternative controlling mechanisms. The variation necessary for evolving these same patterns reside in the mammalian genome. Third, certain reptiles enable us to test first-hand hypotheses regarding the actual evolution of behavioral controlling mechanisms. For example, because of their origin and their parthenogenetic mode of reproduction, the unisexual Cnemidophorus lizard allows us to study directly the evolution of behavioral controlling mechanisms because both the ancestral speies continue to exist. The pattern that emerges from the similarities and differences discovered in the mechanisms that control behavior in these species reveals how novel mechanisms can actually evolve. Fourth, study of reptiles has broadened our concepts of vertebrate sex determination and sexual differentiation because we can study these xxxxxxx. Finally, this work has emphasized that sexuality is not a unitary phenomenon, but consists of multiple components. Principles observed in many mammals are but one of a variety of possible alternatives. Indeed, the only functional association that appears to be inherent to sexuality is the organizing action of the sex steroid hormones.