McDevitt Margaret A, Williams Ben A
Department of Psychology, McDaniel College, Westminster, Maryland 21157, USA.
J Exp Anal Behav. 2003 Nov;80(3):261-72. doi: 10.1901/jeab.2003.80-261.
Pigeons were trained on multiple schedules that provided concurrent reinforcement in each of two components. In Experiment 1, one component consisted of a variable-interval (VI) 40-s schedule presented with a VI 20-s schedule, and the other a VI 40-s schedule presented with a VI 80-s schedule. After extended training, probe tests measured preference between the stimuli associated with the two 40-s schedules. Probe tests replicated the results of Belke (1992) that showed preference for the 40-s schedule that had been paired with the 80-s schedule. In a second condition, the overall reinforcer rate provided by the two components was equated by adding a signaled VI schedule to the component with the lower reinforcer rate. Probe results were unchanged. In Experiment 2, pigeons were trained on alternating concurrent VI 30-s VI 60-s schedules. One schedule provided 2-s access to food and the other provided 6-s access. The larger reinforcer magnitude produced higher response rates and was preferred on probe trials. Rate of changeover responding, however, did not differ as a function of reinforcer magnitude. The present results demonstrate that preference on probe trials is not a simple reflection of the pattern of changeover behavior established during training.
鸽子接受了多种时间表的训练，这些时间表在两个组成部分中都提供了同时强化。在实验1中，一个组成部分是一个40秒可变间隔（VI）时间表与一个20秒VI时间表同时呈现，另一个是40秒VI时间表与一个80秒VI时间表同时呈现。经过长时间训练后，探测测试测量了与两个40秒时间表相关的刺激之间的偏好。探测测试重复了贝尔克（1992）的结果，即显示出对与80秒时间表配对的40秒时间表的偏好。在第二种情况下，通过向强化率较低的组成部分添加一个有信号的VI时间表，使两个组成部分提供的总体强化率相等。探测结果没有变化。在实验2中，鸽子接受了交替的30秒VI与60秒VI同时呈现的时间表训练。一个时间表提供2秒的食物获取时间，另一个提供6秒的食物获取时间。较大的强化量产生了更高的反应率，并且在探测试验中更受青睐。然而，转换反应的速率并没有随着强化量的变化而有所不同。目前的结果表明，探测试验中的偏好并不是训练期间建立的转换行为模式的简单反映。
