Daly H B
Department of Psychology, State University of New York, Oswego 13126.
J Exp Psychol Anim Behav Process. 1989 Jan;15(1):3-13.
Organisms typically prefer situations where reward and nonreward are predictable rather than unpredictable. Although many theories can account for this result (e.g., information theory and delay-reduction theory), a recently developed mathematical model (DMOD) also predicts that subjects prefer the unpredictable reward situation under conditions that substantially decrease aversiveness of unpredictable nonreward (Daly & Daly, 1982). Because a high proportion of reinforced trials (lenient schedule) and alcohol injections decrease aversive conditioning, these variables were tested with rats in five E-maze experiments. A choice to one side of the maze resulted in a stimulus uncorrelated with reward outcome (unpredictable situation). A choice to the other side resulted in stimuli correlated with reward and nonreward (predictable situation). The stimuli were not visible until after the choice was made. A lenient reinforcement schedule resulted in preference for the unpredictable reward situation if rewards were not delayed. Alcohol resulted in preference for the unpredictable reward situation if a medium five-pellet reward was given. A lenient reinforcement schedule combined with an alcohol injection resulted in faster acquisition of the preference for the unpredictable reward situation than did a lenient schedule combined with a saline control injection. These results pose a major challenge to most theories, yet were predicted by DMOD.
生物体通常更喜欢奖励和无奖励可预测的情况，而不是不可预测的情况。尽管许多理论可以解释这一结果（例如信息理论和延迟减少理论），但最近开发的一个数学模型（DMOD）也预测，在大幅降低不可预测的无奖励的厌恶感的条件下，受试者更喜欢不可预测的奖励情况（戴利和戴利，1982）。由于高比例的强化试验（宽松的时间表）和酒精注射会减少厌恶条件作用，因此在五个E型迷宫实验中对大鼠进行了这些变量的测试。选择迷宫的一侧会导致与奖励结果无关的刺激（不可预测的情况）。选择另一侧会导致与奖励和无奖励相关的刺激（可预测的情况）。直到做出选择后，刺激才会可见。如果奖励不延迟，宽松的强化时间表会导致对不可预测的奖励情况的偏好。如果给予中等量的五粒奖励，酒精会导致对不可预测的奖励情况的偏好。与生理盐水对照注射的宽松时间表相比，宽松的强化时间表与酒精注射相结合会导致更快地获得对不可预测的奖励情况的偏好。这些结果对大多数理论构成了重大挑战，但DMOD预测了这些结果。
