The Kamin effect as a function of number of prior unsignaled inescapable shocks.

3 groups of 30 naive male albino Sprague-Dawley rats received 1, 5, or 10 unsignaled inescapable shocks either .02, 2.5, 4, 10, or 24 hrs prior to 1-way avoidance training. For each phase an additional 6 Ss were assigned to a no-shock control group. Trials to criterion in avoidance learning were a nonmonotonic function of time since prior inescapable shock; poorest performance was shown at intermediate shock-acquisition intervals. The locus of maximum performance decrement shifted to longer intervals with increasing numbers of prior inescapable shocks. Also, variability in performance increased, then decreased, as a function of time since inescapable shock in a manner parallel to the changes in performance means. Findings indicate that unsignaled inescapable shock is sufficient to produce Kaminlike effects. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)