Department of Psychology, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
J Exp Anal Behav. 2010 Nov;94(3):327-52. doi: 10.1901/jeab.2010.94-327.
Eight pigeons responded in a three-component concurrent-chains procedure, with either independent or dependent initial links. Relative probability and immediacy of reinforcement in the terminal links were both varied, and outcomes on individual trials (reinforcement or nonreinforcement) were either signaled or unsignaled. Terminal-link fixed-time schedules were varied across components within conditions to yield immediacy ratios of 1∶2, 1∶1 and 2∶1. The probabilities of reinforcement were varied across conditions to yield reinforcer ratios of 1∶5, 1∶2, 2∶1 and 5∶1. Results showed that a model based on the generalized matching law provided a good description of response allocation, accounting for 92% of the variance overall. As expected, sensitivity to probability was greater in the unsignaled conditions. However, sensitivity to immediacy was also greater in the unsignaled conditions, suggesting that the effect of signaling terminal-link outcomes may not be limited to probability but apply to reinforcer variables in general. The effects of signaling can be explained in terms of conditioned reinforcement added to each alternative's outcomes in the matching law. There was some evidence for an interaction between reinforcer probability and immediacy, particularly for the dependent-schedules group, such that sensitivity to immediacy was greater at moderate rather than extreme reinforcer ratios. However, further analysis suggested that this could have been due to a ceiling effect on response allocation imposed by dependent scheduling. Overall, the present results show that the generalized matching law can provide a useful account of choice between outcomes that vary in both probability and immediacy of reinforcement.
八只鸽子在一个三成分同时链程序中做出反应，其中初始链接要么独立，要么依赖。终端链接中的相对概率和即时强化都发生了变化，并且个别试验（强化或非强化）的结果要么被标记，要么未被标记。终端链接的固定时间计划在条件内的各个组件中变化，以产生即时比为 1∶2、1∶1 和 2∶1。强化概率在条件之间变化，以产生强化比为 1∶5、1∶2、2∶1 和 5∶1。结果表明，基于广义匹配律的模型很好地描述了反应分配，总体上解释了 92%的方差。正如预期的那样，在未标记条件下对概率的敏感性更高。然而，在未标记条件下对即时性的敏感性也更高，这表明信号传递终端链接结果的效果可能不仅限于概率，而是适用于一般的强化变量。信号的作用可以根据条件强化来解释，这些强化被添加到匹配律中每个替代结果的条件强化。在强化概率和即时性之间存在一些相互作用的证据，特别是对于依赖计划的组，即对即时性的敏感性在中等而不是极端强化比下更大。然而，进一步的分析表明，这可能是由于依赖计划对反应分配的限制造成的上限效应。总的来说，本研究结果表明，广义匹配律可以为在概率和强化即时性都变化的结果之间的选择提供有用的解释。
