| Abstract: | The effect of four perceptual sets--First Night in a sleep laboratory, Second Night in a sleep laboratory, Shock Avoidance Night, Reward Night--on the distribution of sleep was examined with 12Ss. Both the shock avoidance and the reward conditions gave results similar to those characteristically found in the First Night Effect, i.e., increases in Stage 0, Stage 1, the latency to Stage 4, the number of Awakenings, and the number of Stage Changes coupled with a decrease in Stage 1-REM. The observed effects, however, were minimal and were interpreted as giving evidence for the sturdiness of the sleep process. |
