The retention curve of an incompletely learned avoidance response was investigated, employing rats in a shuttlebox situation. Subjects were given a 15 trial re-learning session 0, 1/2, 1 or 24 hours after original acquisition. Three treatment groups were tested at these intervals: a not-handled group which remained in the shuttlebox during the intersession interval, a handled group which remained in the shuttlebox during the intersession interval, and a group which was returned to a living cage. All treatment groups produced a monotonically decreasing curve as a function of intersession interval. Handling produced a decrement on performance at 0-hour intersession interval; location showed no effect. Results were interpreted in terms of the warm-up decrement and the effects of handling on the arousal of fear. / Thesis / Master of Arts (MA)