West Virginia University, Department of Psychology, Morgantown, WV 26506-6040, USA.
J Exp Anal Behav. 2010 Sep;94(2):209-25. doi: 10.1901/jeab.2010.94-209.
Eight pigeons responded in a concurrent-chains procedure in which terminal-link schedules changed pseudorandomly across sessions. Pairs of terminal-link delays either summed to 15 s or to 45 s. Across sessions, the location of the shorter terminal link changed according to a pseudorandom binary sequence. On some terminal links, food was withheld to obtain start and stop times, measures of temporal control. Log initial-link response ratios stabilized within the first half of each session. Log response ratio was a monotonically-increasing but nonlinear function of programmed log terminal-link immediacy ratio. There was an effect of absolute terminal-link duration on log response ratio: For most subjects, preference for the relatively shorter terminal-link delay was stronger when absolute delays were long than when absolute delays were short. Polynomial regressions and model comparison showed that differences in degree of nonlinearity, not in sensitivity to log immediacy ratio, produced this effect. Temporal control of stop times was timescale invariant with scalar variability, but temporal control of start times was not consistent across subjects or terminal-link durations.
八只鸽子在一个同时链程序中做出了反应，在这个程序中，终端链接的时间表在各次试验中随机变化。终端链接延迟的两个时间要么总和为 15 秒，要么总和为 45 秒。在各次试验中，较短的终端链接的位置根据一个伪随机二进制序列而变化。在一些终端链接上，为了获得开始和停止时间，即时间控制的测量值，鸽子的食物被剥夺。对数初始链接反应率在每个试验的前半段内稳定下来。对数反应率是对数程控终端链接即时性比率的单调递增但非线性函数。终端链接持续时间的绝对值对对数反应率有影响：对于大多数被试来说，当绝对延迟较长时，相对较短的终端链接延迟的偏好更强，而当绝对延迟较短时，这种偏好较弱。多项式回归和模型比较表明，产生这种影响的原因是非线性程度的差异，而不是对数即时性比率的敏感性差异。停止时间的时间控制具有标度不变性和标量可变性，但启动时间的时间控制在不同被试或终端链接持续时间之间并不一致。
