Research productivity in animal learning from 1953 to 2000.

Searches conducted with Medline and PsycInfo showed that the number of publications dealing with learning in animals increased between 1975 and 2000 and that the increase was substantially greater in Medline than in PsycInfo. An examination of major journals dealing with behavioral studies of conditioning and learning for the years 1953, 1963, 1973, 1983, 1993, and 2000 revealed a different pattern of results. The number of papers published in these journals increased from 1953 to 1973 but has been declining steadily since then. However, this decline was partially offset by an increase in the number of experiments published in each paper. Substantially more experiments were published in 2000 than in 1963 or 1953. The number of core authors in the field also peaked in 1973 and has been declining since. However, there were only seven fewer core authors in 2000 than in 1983, and 1983 had as many core authors as 1963. These data suggest that pessimism about the status of behavioral studies of learning is not warranted if research activity is considered over a 40-year period. Furthermore, increased interest in the neural and biological mechanisms of learning should bode well for the status of behavioral research, because one cannot examine the physiological mechanisms of a behavioral process without first clearly understanding the phenomenon at the behavioral level.