Critical Periods in the Development of Social Behavior in Puppies

As a part of a program for the study of heredity and social behavior in dogs, the author and his colleagues have made a thorough study of the development of social behavior in puppies, with the idea of finding out the times at which heredity was most likely to exert its effects. As we did so, we also observed that there were certain periods in which environmental factors were particularly likely to affect behavior. As a result we have, from time to time, reported evidence on what we have called the critical period hypothesis. This idea is one which is basically related to certain clinical ideas concerning the effect of early experience on later mental health and behavioral adjustment. It is therefore important that it be clearly understood.