A comparison of signaled vs. unsignaled free-operant avoidance in wild and domesticated rats
نویسنده
چکیده
Three experiments compared the performance of domesticated hooded rats and nondomesticated black rats under signaled and unsignaled free-operant leverpress avoidance. There was no difference between groups in asymptotic shock rates under unsignaled avoidance; however, the black rats avoided much more successfully when the signal was present, while the hooded rats showed little or no improvement. When a longer signal was employed (10 vs. 5 sec), the effects were essentially the same. The black rats generally had higher response rates, and this difference was most pronounced in extinction. where the hooded rats made very few responses. The domesticated rats received a disproportionately large number of shocks early in the session (warm-up) under unsignaled avoidance, but this tendency was much less pronounced for the black rats. However, both groups showed appreciable amounts of warm-up during signalled avoidance. The findings are discussed in terms of differences in levels of activation/arousal between domesticated and nondomesticated animals.
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