Instrumental escape behavior with extended training

Four groups of nine Ss were run in a straight alley shock situation for 240 trials, 30 per day. Ss received either 180- or 300-V shock and interval intervals (ITI) of 30 or 120 sec. On Day 1 of training, the 300-V groups first started faster than the 180-V groups, but then showed considerable adaptation, resulting in approximately equal performance at the end of Day 1. Over all 8 days, the 180-V group started significantly faster than the 300-V group when a 30-sec ITI was used, but the converse when a 120-sec ITI was used. Over all 8 days, the 300-V groups continued to increase in performance, while the 180-V groups showed a decline after Day 4.