Davison Michael, Cowie Sarah
The University of Auckland, New Zealand.
J Exp Anal Behav. 2022 Jan;117(1):36-52. doi: 10.1002/jeab.723. Epub 2021 Nov 4.
This experiment asks whether timing is affected by animals' discrimination of response-reinforcer contingencies, and if so, how this effect can be understood. Six pigeons were trained on a procedure in which concurrent-schedule reinforcer ratios between left and right keys changed at 30 s after the last reinforcer. One stimulus signaled a reinforcer-ratio reversal from 9:1 to 1:9 on that key, and the other stimulus signaled the inverse reversal, with the key on which these stimuli occurred randomized. Across conditions, the physical difference between the stimuli signaling the two responses was varied and the directional changes in the reinforcer ratio signaled by each stimulus were reversed. Choice changed appropriately across time when the two stimuli were discriminable, and points of subjective equality fell with decreasing stimulus difference. A model which assumed that reinforcers obtained in time bins were redistributed across other time bins according to ogivally changing standard deviations, and between response locations according to an ogivally changing redistribution measure, accounted well for the data. This model was shown to be preferable to one in which across-time redistributions were scalar, and across-location redistribution was constant. These results show the critical importance of stimulus-response-reinforcer discriminability to measures of timing.
本实验探讨时间安排是否受动物对反应-强化物 contingency 的辨别影响，若有影响，该效应如何理解。对六只鸽子进行训练，采用一种程序，即左右按键的并发强化物比率在最后一次强化物出现后 30 秒改变。一种刺激信号表示该按键上强化物比率从 9:1 反转至 1:9，另一种刺激信号表示相反的反转，且呈现这些刺激的按键是随机的。在不同条件下，区分两种反应的刺激之间的物理差异有所变化，且每种刺激所表示的强化物比率的方向变化也被反转。当两种刺激可辨别时，选择随时间适当变化，主观相等点随刺激差异减小而下降。一个模型假设，在时间区间内获得的强化物根据呈 ogivally 变化的标准差在其他时间区间重新分配，并根据呈 ogivally 变化的重新分配度量在反应位置之间重新分配，该模型能很好地解释数据。结果表明，该模型优于一种跨时间重新分配是标量且跨位置重新分配是恒定的模型。这些结果表明刺激-反应-强化物可辨别性对时间测量至关重要。
