Schaal D W, Shahan T A, Kovera C A, Reilly M P
Department of Psychology, West Virginia University, Morgantown 26506-6040, USA.
J Exp Anal Behav. 1998 Mar;69(2):103-22. doi: 10.1901/jeab.1998.69-103.
Three experiments were conducted to test an interpretation of the response-rate-reducing effects of unsignaled nonresetting delays to reinforcement in pigeons. According to this interpretation, rates of key pecking decrease under these conditions because key pecks alternate with hopper-observing behavior. In Experiment 1, 4 pigeons pecked a food key that raised the hopper provided that pecks on a different variable-interval-schedule key met the requirements of a variable-interval 60-s schedule. The stimuli associated with the availability of the hopper (i.e., houselight and keylight off, food key illuminated, feedback following food-key pecks) were gradually removed across phases while the dependent relation between hopper availability and variable-interval-schedule key pecks was maintained. Rates of pecking the variable-interval-schedule key decreased to low levels and rates of food-key pecks increased when variable-interval-schedule key pecks did not produce hopper-correlated stimuli. In Experiment 2, pigeons initially pecked a single key under a variable-interval 60-s schedule. Then the dependent relation between hopper presentation and key pecks was eliminated by arranging a variable-time 60-s schedule. When rates of pecking had decreased to low levels, conditions were changed so that pecks during the final 5 s of each interval changed the keylight color from green to amber. When pecking produced these hopper-correlated stimuli, pecking occurred at high rates, despite the absence of a peck-food dependency. When peck-produced changes in keylight color were uncorrelated with food, rates of pecking fell to low levels. In Experiment 3, details (obtained delays, interresponse-time distributions, eating times) of the transition from high to low response rates produced by the introduction of a 3-s unsignaled delay were tracked from session to session in 3 pigeons that had been initially trained to peck under a conventional variable-interval 60-s schedule. Decreases in response rates soon after the transition to delayed reinforcement were accompanied by decreases in eating times and alterations in interresponse-time distributions. As response rates decreased and became stable, eating times increased and their variability decreased. These findings support an interpretation of the effects of delayed reinforcement that emphasizes the importance of hopper-observing behavior.
进行了三项实验，以检验对鸽子中未发出信号的非重置强化延迟的反应率降低效应的一种解释。根据这种解释，在这些条件下啄键率会下降，因为啄键行为与观察料斗行为交替出现。在实验1中，4只鸽子啄一个食物键，该食物键会升起料斗，前提是在另一个可变间隔时间表键上的啄键符合可变间隔60秒时间表的要求。与料斗可用相关的刺激（即，鸽舍灯和键灯关闭、食物键亮起、食物键啄击后的反馈）在各阶段逐渐消除，同时保持料斗可用性与可变间隔时间表键啄击之间的依赖关系。当可变间隔时间表键啄击未产生与料斗相关的刺激时，啄击可变间隔时间表键的速率降至低水平，而食物键啄击速率增加。在实验2中，鸽子最初在可变间隔60秒的时间表下啄一个键。然后通过安排可变时间60秒的时间表消除料斗呈现与键啄击之间的依赖关系。当啄击速率降至低水平时，条件发生变化，使得每个间隔最后5秒内的啄击将键灯颜色从绿色变为琥珀色。当啄击产生这些与料斗相关的刺激时，尽管不存在啄键与食物的依赖关系，啄击仍以高频率发生。当啄击产生的键灯颜色变化与食物无关时，啄击速率降至低水平。在实验3中，在3只最初在传统可变间隔60秒时间表下训练啄击的鸽子中，逐节跟踪了由引入3秒未发出信号的延迟所导致的从高反应率到低反应率转变的细节（获得的延迟、反应间隔时间分布、进食时间）。向延迟强化转变后不久反应率的下降伴随着进食时间减少和反应间隔时间分布的改变。随着反应率下降并趋于稳定，进食时间增加且其变异性降低。这些发现支持了一种对延迟强化效应的解释，该解释强调了观察料斗行为的重要性。
