Minor T R, Dess N K, Ben-David E, Chang W C
Department of Psychology, University of California, Los Angeles 90024-1563.
J Exp Psychol Anim Behav Process. 1994 Oct;20(4):402-12.
The present study determined whether individual differences in neophobia during an open-field pretest predict vulnerability to inescapable electric shock, as measured by 2 tests of learned helplessness in rats. Shuttle-escape latencies and saccharin finickiness increased across groups that had received increasing numbers of inescapable shocks 24 hr earlier. Dispersion in the test measure as well as the percentage of variance explained by pretest neophobia were greater when no or few shocks were delivered in the interpolated stress phase. Pretest neophobia was positively related to stress vulnerability in both tests under these conditions. Further increments in stressor severity overwhelmed even the most stress-resistant rats, thereby decreasing dispersion in the test measure and eliminating the predictive value of pretest neophobia. This pattern of outcomes was more robust for the shuttle-escape measure of helplessness.
本研究通过大鼠习得性无助的两项测试，确定旷场预测试中对新事物的恐惧的个体差异是否能预测对不可逃避电击的易感性。在24小时前接受了越来越多不可逃避电击的各组中，穿梭逃避潜伏期和糖精挑剔程度均有所增加。当在插入的应激阶段未施加电击或仅施加少量电击时，测试指标的离散度以及预测试新事物恐惧所解释的方差百分比更大。在这些条件下，两项测试中预测试新事物恐惧均与应激易感性呈正相关。应激源严重程度的进一步增加甚至压垮了最具应激抵抗力的大鼠，从而降低了测试指标的离散度，并消除了预测试新事物恐惧的预测价值。这种结果模式在无助的穿梭逃避测量中更为显著。
