INTERTRIAL INTERVALS AND SHOCK SCHEDULES IN ESCAPE TRAINING

80 rats received 64 escape training trials with intertrial intervals (ITIs) of either 1 min., 5 min., 1 hr., or 24 hr. and shock-presentation schedules of 100 or 50%. The latter schedule interspersed shock and nonshock trials. Escape performance increased reliably with decreasing ITIs for the 100% schedule and, on shock trials alone, for the 50% schedule. Performance under the latter schedule was unrelated to ITI for shock and nonshock trials combined and was reliably inferior to performance under the 100% schedule at each ITI except 24 hr. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.