Roscoe E M, Iwata B A, Kahng S
University of Florida 32611, USA.
J Appl Behav Anal. 1999 Winter;32(4):479-93. doi: 10.1901/jaba.1999.32-479.
We compared results obtained in two previous studies on reinforcer identification (Fisher et al., 1992; Pace, Ivancic, Edwards, Iwata, & Page, 1985) by combining methodologies from both studies. Eight individuals with mental retardation participated. During Phase 1, two preference assessments were conducted, one in which stimuli were presented singly (SS method) and one in which stimuli were presented in pairs (PS method). Based on these results, two types of stimuli were identified for each participant: High-preference (HP) stimuli were those selected on 75% or more trials during both preference assessments; low-preference (LP) stimuli were those selected on 100% of the SS trials but on 25% or fewer of the PS trials. During Phase 2, the reinforcing effects of HP and LP stimuli were evaluated in reversal designs under two test conditions: concurrent and single schedules of continuous reinforcement. Two response options were available under the concurrent-schedule condition: One response produced access to the HP stimulus; the other produced access to the LP stimulus. Only one response option was available under the single-schedule condition, and that response produced access only to the LP stimulus. Results indicated that 7 of the 8 participants consistently showed preference for the HP stimulus under the concurrent schedule. However, when only the LP stimulus was available during the single-schedule condition, response rates for 6 of the 7 participants were as high as those observed for the HP stimulus during the concurrent-schedule condition (1 participant showed no reinforcement effect). These results indicate that, although the concurrent-schedule procedure is well suited to the assessment of relative reinforcement effects (preference for one reinforcer over another), absolute reinforcement effects associated with a given stimulus may be best examined under single-schedule conditions.
我们通过结合两项先前关于强化物识别研究（Fisher等人，1992年；Pace、Ivancic、Edwards、Iwata和Page，1985年）的方法，比较了两项研究所得的结果。八名智力障碍个体参与了研究。在第一阶段，进行了两项偏好评估，一项是单个呈现刺激（单刺激法），另一项是成对呈现刺激（配对刺激法）。基于这些结果，为每位参与者确定了两种类型的刺激：高偏好（HP）刺激是在两项偏好评估中75%或更多试验中被选中的刺激；低偏好（LP）刺激是在单刺激试验的100%中但在配对刺激试验的25%或更少试验中被选中的刺激。在第二阶段，在两种测试条件下的反转设计中评估了HP和LP刺激的强化效果：连续强化的并发和单一程序。在并发程序条件下有两种反应选项：一种反应可获得HP刺激；另一种反应可获得LP刺激。在单一程序条件下只有一种反应选项，且该反应仅能获得LP刺激。结果表明，8名参与者中有7名在并发程序下始终表现出对HP刺激的偏好。然而，当在单一程序条件下只有LP刺激可用时，7名参与者中有6名的反应率与在并发程序条件下观察到的HP刺激的反应率一样高（1名参与者未表现出强化效果）。这些结果表明，尽管并发程序非常适合评估相对强化效果（对一种强化物相对于另一种强化物的偏好），但与给定刺激相关的绝对强化效果可能在单一程序条件下进行最佳检验。
