| Abstract: | Three experiments investigated the effects of restraint and of inescapable fixed duration preshocks on subsequent shuttlebox escape-from-shock learning. Fixed-intensity preshock, random-intensity preshock, and no-preshock conditions were included in each experiment. In Experiment 1, restraining the rat in a harness prior to escape training retarded escape acquisition. There was no effect of preshock. In Experiment 2, both restraint and high fixed-intensity (1.0 mA) preshock retarded escape acquisition, when escape training occurred either immediately or 24 hr after preshock. In Experiment 3, movement was punished by positively correlating preshock intensity with the rat's movement; this treatment retarded escape conditioning. No effects were found for low fixed-intensity or random-intensity preshock nor for a condition in which movement was rewarded during preshock. The retarding effects of restraint and certain types of preshock were explained in terms of interfering instrumental responses. |
