Periods of Early Development and the Effects of Stimulation and Social Experiences in the Canine

It is not capacity that explains the differences that exist between individuals, because Most seem to have far more capacity than they will ever use. The differences that exist between individuals seem to be related to something else. Researchers have studied these phenomena and have looked for new ways to stimulate individuals to improve their natural abilities. Some of the methods discovered have produced lifelong effects. Today, many of the differences between individuals can now be explained by the use of early stimulation methods, socialization, and enrichment experiences. For example, early life has been found to be a time when the physical immaturity of an organism is susceptible and responsive to a restricted but important class of stimuli. Because of its importance, many studies have focused on the first year of life. Newborn pups are different from adult dogs in several respects. When born, pups' eyes are closed, their temperature is subnormal, and their digestive system has a limited capacity, requiring periodic stimulation by their dam, who routinely licks them to promote digestion. Other mammals such as mice and rats are also born with limitations, and they also have been found to show a similar sensitivity to the effects of early stimulation. Studies show that removing them from their nest for 3 min each day during the first 5-10 days of life causes body temperatures to fall below normal. This mild form of stress is sufficient to stimulate hormonal, adrenal, and pituitary systems. When tested later as adults, these same animals were better able to withstand stress than litter-mates who were not exposed to the same early stress exercises. As adults, they responded to stress in "a graded" fashion, whereas their nonstressed littermates responded in an "all or nothing way." The results show that early stimulation can have positive results but must be used with caution. Too much stress can cause pathologic adversities rather than physical or psychologic superiority. Socialization and enrichment experiences have also been found to make important differences in the development of the adult dog. (C) 2009 Elsevier Inc. All rights reserved.