ABSTRACT
There is a considerable body of evidence suggesting that infantile amnesia is not restricted to man but can be observed in a number of species (for recent reviews, see Campbell & Coulter, 1976; Campbell, Riccio, & Rohrbaugh, 1971; Campbell & Spear, 1972). It is not known whether or not the mechanism(s) that underly this inability to remember early events is the same in all species. It is not even clear if this apparently similar deficit is really the same phenomenon. For example, humans seem to have complete amnesia for events occurring before 3 to 4 years of age with adult-like memory abilities for events occurring very shortly thereafter (Waldfogel, 1948). In contrast, rats (as well as dogs and monkeys) show, over relatively long periods of development, only slow and gradual improvements in long-term retention (Campbell & Campbell, 1962). However, this difference could be explained by differences in the way these memory effects have been measured: Human data are all largely unverified anecdotal recollections, unlike the infrahuman data, which consist of retests or of some kind of controlled recognition tests. Thus many researchers, including myself, feel justified in accepting the working hypothesis that infantile amnesia is a general enough phenomenon that it can be fruitfully studied in a nonhuman species such as the rat.
