Huang Xuan, Lu Hongjing, Tjan Bosco S, Zhou Yifeng, Liu Zili
School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.
J Vis. 2007 Jul 27;7(10):14.1-10. doi: 10.1167/7.10.14.
The classic view that perceptual learning is information selective and goal directed has been challenged by recent findings showing that subthreshold and task-irrelevant information can induce perceptual learning. This study demonstrates a limit on task-irrelevant learning as exposure to suprathreshold task-irrelevant signals failed to induce perceptual learning. In each trial, two random-dot motion stimuli were presented in a two-alternative forced-choice task. Observers either decided which of the two contained a coherent motion signal (detection task), or whether the coherent motion direction was clockwise or counterclockwise relative to a reference direction (discrimination task). Whereas the exact direction of the coherent motion signal was irrelevant to the detection task, detection of the coherent motion signal was necessary for the discrimination task. We found that the detection trainees improved only their detection but not discrimination sensitivity, whereas the discrimination trainees improved both. Therefore, the importance of task relevance was demonstrated in both detection and discrimination learning. Furthermore, both detection and discrimination training along a single pedestal direction transferred to a broad range of pedestal directions. The profile of the discrimination transfer (as a function of pedestal direction) narrowed for the discrimination trainees.
传统观点认为知觉学习具有信息选择性且是目标导向的，但最近的研究结果对这一观点提出了挑战，这些结果表明阈下及与任务无关的信息能够引发知觉学习。本研究证明了与任务无关学习存在局限性，因为暴露于阈上与任务无关信号未能引发知觉学习。在每次试验中，两个随机点运动刺激会在二选一的强制选择任务中呈现。观察者要么判断两个刺激中哪一个包含连贯运动信号（检测任务），要么判断连贯运动方向相对于参考方向是顺时针还是逆时针（辨别任务）。连贯运动信号的确切方向与检测任务无关，但连贯运动信号的检测对于辨别任务是必要的。我们发现，检测训练组仅提高了其检测能力，而未提高辨别敏感度，而辨别训练组两者都得到了提高。因此，任务相关性在检测和辨别学习中均得到了证明。此外，沿着单一基座方向进行的检测和辨别训练均能迁移到广泛的基座方向。辨别训练组的辨别迁移情况（作为基座方向的函数）的曲线变窄了。
