Poling A, Thompson T
J Exp Anal Behav. 1977 Nov;28(3):271-83. doi: 10.1901/jeab.1977.28-271.
When food was initially available to rats under a fixed-interval 26-second schedule and each liquid-reinforced lever press delayed food availability 8 seconds, suppression of liquid-reinforced lever pressing and liquid consumption occurred when the liquid presented was 4, 8, 16, 32, and 0% ethanol. Suppression did not occur in yoked-control animals, which received food coincidentally with experimental animals but were not directly exposed to the delay dependency. After exposure to the food schedule, each ethanol solution served as a reinforcer in the absence of food presentation. Delaying food availability for increasingly long periods (8 to 2048 seconds) suppressed ethanol-reinforced lever pressing and consumption relative to baseline levels, with the maximum decrease being below the level maintained in the absence of food. However, degree of suppression did not increase monotonically with delay length. Liquid-reinforced performance of yoked-control animals indicated that suppression did not result from changes in the sequencing of food presentation alone.
当大鼠最初在固定间隔26秒的时间表下可获取食物，且每次液体强化的杠杆按压会使食物供应延迟8秒时，当所呈现的液体为4%、8%、16%、32%和0%乙醇时，液体强化的杠杆按压和液体消耗会受到抑制。在配对对照动物中未出现抑制现象，这些动物与实验动物同时获得食物，但未直接经历延迟依赖。在接触食物时间表后，每种乙醇溶液在不呈现食物的情况下充当强化物。将食物供应延迟的时间越来越长（8至2048秒），相对于基线水平，乙醇强化的杠杆按压和消耗受到抑制，最大降幅低于无食物时维持的水平。然而，抑制程度并未随延迟长度单调增加。配对对照动物的液体强化表现表明，抑制并非仅由食物呈现顺序的变化所致。
