Modulation of aversively motivated learning in rats adapted to a cold stressor.

Two experiments studied effects of adaptation to cold water stress upon learning in two aversively motivated (shock) tasks. Experiment 1 found animals previously experiencing cold water stress exhibited more tolerance to shock, having shorter latencies, in an approach-avoidance conflict situation than non-treated controls. In Experiment 2, animals with previous cold water stress experience exhibited longer response latencies than controls in an active-avoidance task. These findings provide evidence that adaptation to a noncontingent stressor can modulate behavioral responses which suggest increased tolerance.