Amygdalectomized and control Ss were conditioned to avoid shock in a modified Miller box, then trained for the wheel-turning response without shock. Amygdalectomized Ss were slower to acquire avoidance responses, had longer latency scores than normal control Ss, and showed more fear responses than normal controls during the 1st conditioning session. Number of crouching responses and latency scores were positively correlated for experimental and sham-operated Ss. 1 amygdalectomized S turned the wheel, compared with 4 sham-operated, and 3 normal-control Ss. Ss failing to respond "froze" more than all Ss which turned the wheel. Impairments following amygdalectomy were attributed to either fear reduction, fear overarousal, or deficit in active avoidance. Difficulties for each hypothesis were discussed. (15 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)