Williams B A, Dunn R
Department of Psychology, University of California-San Diego, La Jolla 92093-0109.
J Exp Anal Behav. 1991 Jan;55(1):37-46. doi: 10.1901/jeab.1991.55-37.
Pigeons were presented with a concurrent-chains schedule in which both choice alternatives led to the same terminal-link stimulus, which was followed by food. Superimposed on the food-reinforced presentations of the terminal-link stimulus was a second schedule of presentations of the same stimulus that were followed by no food. The absolute number of these no-food stimulus presentations was held constant while their relative frequency assigned to one or the other choice alternative was systematically varied. Preference for a given choice alternative tracked the relative frequency of these stimulus presentations, thus demonstrating that they served as reinforcers. These results resolve conflicts in the literature regarding the effect of conditioned reinforcement on choice.
给鸽子呈现一种并发链程序，其中两个选择项都通向相同的终端链接刺激，随后是食物。在终端链接刺激的食物强化呈现之上叠加了同一刺激的第二种呈现程序，这种呈现之后没有食物。这些无食物刺激呈现的绝对数量保持不变，而分配给其中一个或另一个选择项的相对频率则系统地变化。对给定选择项的偏好跟踪这些刺激呈现的相对频率，从而表明它们起到了强化物的作用。这些结果解决了文献中关于条件强化对选择的影响的冲突。
