Caveats in the study of perinatal behavioral development: utility of fetal study.

Study of behavior during development presents psychobiologists and neurobiologists with a unique set of problems that should be addressed in the design and analysis of experiments. Some of these caveats have become apparent only with the recent growth in research with subjects around the time of birth. For example, physiological regulation within the maternal-infant dyad, litter effects, the influence of context at the time of testing on performance, and dissociation of age-related change and experience, all are important experimental considerations in developmental study. Manipulation and measurement of behavioral variables in the fetus in vivo can provide one means for circumventing many of the methodological pitfalls that are associated with behavioral study of newborn subjects.