Early stimulation of rodents: a critical review of present interpretations

It is widely accepted that extra stimulation, when administered to infant laboratory rodents, has adaptive consequences. Presumed benefits are: (1) accelerated growth and development, (2) reduced emotional reactivity, (3) improved learning performance, and (4) more adaptive physiological stress responses. Levine has explained these benefits by considering such stimulation to compensate for the impoverished rearing conditions of the laboratory. However, ecological studies of the natural microhabitats of rodents suggest that laboratory conditions are over-stimulative for the very young. The presumed benefits are reviewed and the validity or adaptiveness of each is concluded to be very questionable. The prevalent misinterpretation is attributed to an anthropocentric research orientation.