Pietras C J, Hackenberg T D
Department of Psychology, University of Florida, Gainesville 32611-2250, USA.
J Exp Anal Behav. 2000 Sep;74(2):147-64. doi: 10.1901/jeab.2000.74-147.
Three experiments were conducted to examine pigeons' postponement of signaled extinction periods (timeouts) from a schedule of food reinforcement when such responding neither decreased overall timeout frequency nor increased the overall frequency of food reinforcement. A discrete-trial procedure was used in which a response during the first 5 s of a trial postponed an otherwise immediate 60-s timeout to a later part of that same trial but had no effect on whether the timeout occurred. During time-in periods, responses on a second key produced food according to a random-interval 20-s schedule. In Experiment 1, the response-timeout interval was 45 s under postponement conditions and 0 s under extinction conditions (responses were ineffective in postponing timeouts). The percentage of trials with a response was consistently high when the timeout-postponement contingency was in effect and decreased to low levels when it was discontinued under extinction conditions. In Experiment 2, the response-timeout interval was also 45 s but postponement responses increased the duration of the timeout, which varied from 60 s to 105 s across conditions. Postponement responding was maintained, generally at high levels, at all timeout durations, despite sometimes large decreases in the overall frequency of food reinforcement. In Experiment 3, timeout duration was held constant at 60 s while the response-timeout interval was varied systematically across conditions from 0 s to 45 s. Postponement responding was maintained under all conditions in which the response-timeout interval exceeded 0 s (the timeout interval in the absence of a response). In some conditions of Experiment 3, which were designed to control for the immediacy of food reinforcement and food-correlated (time-in) stimuli, responding postponed timeout but the timeout was delayed whether a response occurred or not. Responding was maintained for 2 of 3 subjects, suggesting that behavior was negatively reinforced by timeout postponement rather than positively reinforced by the more immediate presentation of food or food-correlated (time-in) stimuli.
进行了三项实验，以研究鸽子在食物强化程序中对信号消退期（暂停期）的延迟反应，此时这种反应既不会降低整体暂停频率，也不会增加食物强化的整体频率。采用了离散试验程序，即在试验的前5秒内的一次反应会将原本立即开始的60秒暂停推迟到同一试验的稍后部分，但对暂停是否发生没有影响。在非暂停期，对第二个按键的反应根据随机间隔20秒的程序产生食物。在实验1中，在延迟条件下反应-暂停间隔为45秒，在消退条件下为0秒（反应在延迟暂停方面无效）。当暂停延迟的偶然性有效时，有反应的试验百分比始终很高，而在消退条件下该偶然性停止时，该百分比降至低水平。在实验2中，反应-暂停间隔也为45秒，但延迟反应增加了暂停的持续时间，在不同条件下从60秒到105秒不等。尽管食物强化的整体频率有时大幅下降，但在所有暂停持续时间下，延迟反应通常都保持在较高水平。在实验3中，暂停持续时间保持在60秒不变，而反应-暂停间隔在不同条件下从0秒到45秒系统地变化。在反应-暂停间隔超过0秒（无反应时的暂停间隔）的所有条件下，延迟反应都得以维持。在实验3的一些旨在控制食物强化和与食物相关（非暂停期）刺激的即时性的条件下，反应延迟了暂停，但无论是否有反应，暂停都会延迟。三名受试者中有两名维持了反应，这表明行为是通过暂停延迟得到负强化，而不是通过更即时地呈现食物或与食物相关（非暂停期）的刺激得到正强化。
