A note on Lester’s theory of exploratory behavior

Abstract

Some aspects of the defecation and ambulation behavior of rats in an open field are difficult to reconcile with Lester's (1967) theory of exploratory behavior. To account for the sex difference in the correlation between the two measures, it is necessary to assurne that fe males are more fearful than males, which does not accord with their defecation and ambulation scores. More critically, females show a negative defecation/ambulation correlation yet faH to explore more with repeated testing as predicted by the theory. Lester (1967) has proposed a theory of exploratory behavior according to which the probabiIity of a rat approaching a novel stimulus first increases and then decreases as a function of the fear evoked by that stimulus. Supporting this theory is abundant evidence Iinking increased fear with reduced exploration (e.g.,

Behavioral and hormonal effects of hippocampal lesions on male and female rats

“…On several tasks, female animals differ from males in the same direction that animals with hippocampal lesions differ from normals. Females have greater locomotor activity than males (Smith, 1972;Russell , 1971; Denenberg & Morton , 1962;Thorne & Linder, 1971 ;Valle, 1970), as rats with hippocampal lesions are more active than normals (Teitelbaum & Milner , 1963 ;Douglas & Isaacson , 1964;Strong & Jackson, 1970). Like females (Smith, 1972), animals with hippocampal lesions made more errors in Hebb-Williams mazes (Kimble, 1963).…”

Sex differences in rats’ stationary-cage activity measured by observation and automatic recording

“…Previous reports are based on exposure periods of the order of a few minutes, and so may be regarded as studies of behavior in a "novel" or "stressful" setting. For this reason, sex differences in activity are frequently regarded as indicating a sex difference in response to novelty, which may be related to the presumed greater fearfulness of male rats (Gray, 1971;Russell, 1971). However, it is not clear how, or indeed whether, such differences are affected by habituation to the test apparatus.…”