Whitaker S, Lowe C F, Wearden J H
School of Psychology, Keele University, Keele, Staffordshire, United Kingdom.
Behav Processes. 2008 Jan;77(1):33-42. doi: 10.1016/j.beproc.2007.06.001. Epub 2007 Jun 13.
Rats were trained on mixed-fixed-interval (FI) schedules, with component FIs of 30 and 60s. The probability of reinforcement according to FI 30s varied between conditions, across values of 0.1, 0.3, 0.5, 0.7 and 0.9. When response rate in the 60s intervals was measured, separate response peaks, one close to 30s, the other at 60s, could be identified when the probability of reinforcement at 30s was 0.3 or greater. Nonlinear regression found that the location of the earlier peak was always close to 30s, that the coefficient of variation of the response functions at 30 and 60s were unaffected by reinforcement probability, but that the 30s component appeared to be timed slightly more precisely than the 60s one. Response rate at around 30s increased with increasing probability of reinforcement according to FI 30s, but responding at 60s was unaffected by reinforcement probability. The data are discussed with respect to a number of contemporary models of animal timing (scalar expectancy theory, the Behavioural Theory of Timing and the Learning to Time model), and a recent account of response output on FI-like schedules.
大鼠在混合固定间隔（FI）时间表上接受训练，其组成部分的固定间隔为30秒和60秒。根据30秒固定间隔的强化概率在不同条件下有所不同，取值范围为0.1、0.3、0.5、0.7和0.9。当测量60秒间隔内的反应率时，当30秒时的强化概率为0.3或更高时，可以识别出单独的反应峰值，一个接近30秒，另一个在60秒。非线性回归发现，较早峰值的位置总是接近30秒，30秒和60秒时反应函数的变异系数不受强化概率的影响，但30秒的组成部分似乎比60秒的部分计时更精确。根据30秒固定间隔，30秒左右的反应率随着强化概率的增加而增加，但60秒时的反应不受强化概率的影响。本文根据一些当代动物计时模型（标量期望理论、计时行为理论和计时学习模型）以及最近关于类似FI时间表上反应输出的描述对这些数据进行了讨论。
