Weatherly J N, McSweeney F K, Swindell S
Department of Psychology, Washington State University, Pullman, WA 99164-4820, USA.
Behav Processes. 1997 Feb;39(3):279-89. doi: 10.1016/s0376-6357(96)00759-0.
The present study was an attempt to determine the factors to which subjects sensitize and/or habituate within experimental sessions. Rats pressed a lever and pigeons pecked a key for food reinforcers delivered during a 60 min session. In experiment 1, subjects initially responded on a simple variable-interval 30 s schedule that consisted of 25 intervals. In subsequent conditions, the number of intervals in the series was decreased until subjects responded on a simple fixed-interval 30 s schedule. In experiment 2, subjects always responded on a variable-interval 15 s schedule that resulted in a stimulus change. The probability that a food reinforcer would accompany the stimulus change varied across conditions. Results showed that within-session patterns of responding did not change for either species with changes in the temporal pattern of reinforcer delivery (experiment 1). The within-session response patterns generally became flatter with decreases in the probability of food delivery for both species (experiment 2). The present results indicate that subjects are sensitizing and/or habituating to the reinforcer itself and/or to some aspect of its delivery. They also help to highlight the strength of sensitization-habituation as an explanation for within-session changes in responding.
本研究旨在确定在实验过程中，实验对象对哪些因素产生敏感化和/或习惯化。大鼠按压杠杆，鸽子啄按键，以获取在60分钟实验过程中提供的食物强化物。在实验1中，实验对象最初按照简单的可变间隔30秒的时间表做出反应，该时间表由25个间隔组成。在随后的条件下，系列中的间隔数量减少，直到实验对象按照简单的固定间隔30秒的时间表做出反应。在实验2中，实验对象始终按照可变间隔15秒的时间表做出反应，这导致了刺激的变化。食物强化物伴随刺激变化出现的概率在不同条件下有所不同。结果表明，对于两种物种而言，随着强化物发放时间模式的变化，实验过程中的反应模式并未改变（实验1）。随着两种物种食物发放概率的降低，实验过程中的反应模式总体上变得更加平缓（实验2）。目前的结果表明，实验对象正在对强化物本身和/或其发放的某些方面产生敏感化和/或习惯化。它们也有助于突出敏感化-习惯化作为实验过程中反应变化解释的有力程度。
