Nevin John A, Shahan Timothy A, Odum Amy L
University of New Hampshire, Durham, NH, USA.
Q J Exp Psychol (Hove). 2008 Sep;61(9):1400-9. doi: 10.1080/17470210701557597.
Behavioural contrast is an inverse relation between the response rate in one component of a multiple schedule and the reinforcer rate in an alternated component. To explore possible contrast effects in accuracy as well as response rate, four pigeons were trained in multiple schedules where key pecking produced delayed matching-to-sample trials on a variable-interval schedule. Reinforcer probability for correct matches was constant at .3 in one component, and the conditions of reinforcement were varied in the second component. In Experiment 1, the varied component arranged the same contingencies as the constant component but with reinforcer probabilities of .9 or .1 across conditions. In the varied component, both response rate and accuracy of delayed matching were directly related to reinforcer probability; in the constant component, however, contrast effects on response rate were weak, and there was no evidence of contrast in accuracy of matching. In Experiment 2, the varied component was either variable interval with immediate food reinforcement or extinction. Reliable contrast effects were obtained in both response rate and in accuracy of matching in the constant component, and their magnitudes were correlated within and between subjects. The results of Experiment 2 join previous findings of covariation in the effects of reinforcement on free-operant responding and accuracy of discrimination.
行为对比是指在多重强化程序的一个成分中的反应率与交替成分中的强化率之间的反向关系。为了探究准确性以及反应率方面可能存在的对比效应，对4只鸽子进行了多重强化程序训练，在该程序中，啄键会在可变间隔程序上产生延迟的样本匹配试验。在一个成分中，正确匹配的强化概率恒定为0.3，在第二个成分中，强化条件有所变化。在实验1中，变化的成分安排了与恒定成分相同的偶然事件，但在不同条件下强化概率分别为0.9或0.1。在变化的成分中，延迟匹配的反应率和准确性都与强化概率直接相关；然而，在恒定成分中，对反应率的对比效应较弱，并且没有匹配准确性方面存在对比的证据。在实验2中，变化的成分要么是立即给予食物强化的可变间隔，要么是消退。在恒定成分中，反应率和匹配准确性方面都获得了可靠的对比效应，并且它们的大小在个体内部和个体之间都具有相关性。实验2的结果与先前关于强化对自由操作反应和辨别准确性的影响存在协变的研究结果一致。
