Batsell W R
Department of Psychology, Southern Methodist University, Dallas, TX 75275, USA.
Physiol Behav. 1997 Mar;61(3):437-46. doi: 10.1016/s0031-9384(96)00458-1.
A series of experiments examined recovery from context blocking across a retention interval. In two flavor-aversion studies, rats received 0, 2, or 4 context + US pairings in Phase 1, a flavor + US pairing in Phase 2, and flavor testing after a 3-day or a 14-day retention interval. The procedures in Experimental 1 were performed in a novel context, whereas Experiment 2 was conducted in a moderately familiar context. In Experiment 1, the effects of 2 context + US pairing dissipated over the retention interval (i.e., the taste aversion increased in strength), but the effects of 4 context + US pairings did not change. In Experiment 2, no context blocking was observed after 2 context + US pairings, but the effects of 4 context + US pairings decreased across the retention interval. These studies are the first to show recovery from context blocking across a retention interval following single-element conditioning. Furthermore, Experiment 3 demonstrated that extinction of the context prior to taste conditioning eliminated context blocking, and Experiment 4 showed that weak taste aversions do not increase in strength across a retention interval. It is proposed that forgetting of the context-US association across an extended retention interval is the mechanism underlying recovery from context blocking.
一系列实验研究了在一个保持间隔内从情境阻断中的恢复情况。在两项味觉厌恶研究中，大鼠在第一阶段接受0次、2次或4次情境+非条件刺激配对，在第二阶段接受一次味觉+非条件刺激配对，并在3天或14天的保持间隔后进行味觉测试。实验1的程序在一个新的情境中进行，而实验2在一个中等熟悉的情境中进行。在实验1中，2次情境+非条件刺激配对的效果在保持间隔内逐渐消失（即味觉厌恶的强度增加），但4次情境+非条件刺激配对的效果没有变化。在实验2中，2次情境+非条件刺激配对后未观察到情境阻断，但4次情境+非条件刺激配对的效果在保持间隔内减弱。这些研究首次表明，在单元素条件作用后，在一个保持间隔内从情境阻断中可以恢复。此外，实验3表明，在味觉条件作用之前对情境进行消退消除了情境阻断，实验4表明，微弱的味觉厌恶在保持间隔内强度不会增加。有人提出，在延长的保持间隔内对情境-非条件刺激关联的遗忘是从情境阻断中恢复的潜在机制。
