Stimulus discriminability may bias value-based probabilistic learning

Reinforcement learning tasks are often used to assess participants' tendency to learn more from the positive or more from the negative consequences of one's action. However, this assessment often requires comparison in learning performance across different task conditions, which may differ in the relative salience or discriminability of the stimuli associated with more and less rewarding outcomes, respectively. To address this issue, in a first set of studies, participants were subjected to two versions of a common probabilistic learning task. The two versions differed with respect to the stimulus (Hiragana) characters associated with reward probability. The assignment of character to reward probability was fixed within version but reversed between versions. We found that performance was highly influenced by task version, which could be explained by the relative perceptual discriminability of characters assigned to high or low reward probabilities, as assessed by a separate discriminati...

强化学习（Reinforcement Learning）任务常被用于评估被试在自身行为结果中，更倾向于从正向还是负向结果中习得经验的行为偏向。然而，此类评估通常需要在不同任务条件下对比学习表现，而不同任务条件下，与高奖励结果、低奖励结果绑定的刺激的相对显著性与可辨别性往往存在差异。为解决这一问题，在首轮系列研究中，我们采用同一经典概率学习任务的两种版本对被试开展测试。两种版本的差异在于与奖励概率绑定的（平假名，Hiragana）刺激字符。单版本内，字符与奖励概率的绑定关系固定不变，但两个版本间的绑定关系恰好相反。研究结果显示，任务版本对学习表现存在显著影响，该效应可通过分配至高、低奖励概率的字符的相对感知可辨别性加以解释，而该可辨别性由一项独立的辨别任务予以评估（原文此处截断）。