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.