Fantino E, Freed D, Preston R A, Williams W A
Department of Psychology, University of California San Diego, La Jolla 92093-0109.
J Exp Anal Behav. 1991 Mar;55(2):177-88. doi: 10.1901/jeab.1991.55-177.
A potential weakness of one formulation of delay-reduction theory is its failure to include a term for rate of conditioned reinforcement, that is, the rate at which the terminal-link stimuli occur in concurrent-chains schedules. The present studies assessed whether or not rate of conditioned reinforcement has an independent effect upon choice. Pigeons responded on either modified concurrent-chains schedules or on comparable concurrent-tandem schedules. The initial link was shortened on only one of two concurrent-chains schedules and on only one of two corresponding concurrent-tandem schedules. This manipulation increased rate of conditioned reinforcement sharply in the chain but not in the tandem schedule. According to a formulation of delay-reduction theory, when the outcomes chosen (the terminal links) are equal, as in Experiment 1, choice should depend only on rate of primary reinforcement; thus, choice should be equivalent for the tandem and chain schedules despite a large difference in rate of conditioned reinforcement. When the outcomes chosen are unequal, however, as in Experiment 2, choice should depend upon both rate of primary reinforcement and relative signaled delay reduction; thus, larger preferences should occur in the chain than in the tandem schedules. These predictions were confirmed, suggesting that increasing the rate of conditioned reinforcement on concurrent-chains schedules may have no independent effect on choice.
延迟减少理论的一种表述方式的一个潜在弱点在于，它没有纳入条件强化率这一术语，也就是说，在并发链程序中最终环节刺激出现的速率。本研究评估了条件强化率是否对选择有独立影响。鸽子在修改后的并发链程序或可比的并发串联程序上做出反应。在两个并发链程序中的仅一个以及两个相应的并发串联程序中的仅一个上缩短了初始环节。这种操作在链程序中大幅提高了条件强化率，但在串联程序中却没有。根据延迟减少理论的一种表述，当所选择的结果（最终环节）相等时，如在实验1中，选择应该仅取决于初级强化率；因此，尽管条件强化率有很大差异，串联程序和链程序的选择应该是等效的。然而，当所选择的结果不相等时，如在实验2中，选择应该取决于初级强化率和相对信号延迟减少；因此，链程序中的偏好应该比串联程序中更大。这些预测得到了证实，表明在并发链程序上提高条件强化率可能对选择没有独立影响。
