认知与发展心理学研究室知识库

人类认知活动中，绝大部分输入信息是为非意识方式所处理。知觉学习是增强对所输入感知觉信息的处理的最有效方式之一。现阶段的知觉学习研究，主要关注于主动有意识地处理信息时的感知觉能力增强,对以非意识方式处理信息时的感知觉能力增强，即对基于暴露知觉学习，开展得却很不充分，对其特征表现与发生规律知之甚少。本研究应用同刺激异任务范式，训练被试对刺激某一属性进行辨别，控制任务无关属性，对基于暴露知觉学习的特性与发生规律展开系统研究，将有助于加深对知觉学习的全面理解。

研究一考察暴露刺激属性强度对基于暴露知觉学习的影响。探究训练被试对Gabor 阵列的某一刺激属性进行辨别时，运动方向和整体朝向辨别学习的特特点。实验结果显示，整体运动方向和整体朝向辨别两种训练任务的学习速率和学习幅度均不受暴露刺激属性强度的影响；运动方向学习后，基于暴露的整体朝向辨别学习可以发生，且能传递到其他未暴露的整体朝向强度水平；整体朝向辨别学习后，基于暴露的运动方向学习并未发生，表明基于暴露知觉学习可能具有刺激属性间非对称性。

研究二旨在进一步探究基于暴露知觉学习的特征表现，包括基于暴露知觉学习的发生条件、眼间特异性、学习效应可持续性等。实验结果显示，基于暴露的整体朝向学习的发生依赖于无关刺激的整体而非局部信息。采用单眼训练的刺激属性间传递与采用双眼训练的结果相同，即无论单眼还是双眼训练，运动方向学习后，基于暴露的整体朝向学习均发生；朝向辨别学习后，基于暴露的运动方向学习均未发生。基于暴露的整体朝向学习效应在训练后至少可以保持45 天。

研究三将基于暴露知觉学习拓展到其他刺激属性及其对应任务，包括对比度、朝向、运动方向和运动速率等，探究基于暴露知觉学习的普遍性。实验结果显示，完成对比度、朝向与运动速率等任一属性的辨别学习后，除了运动方向辨别任务外，暴露的其他刺激属性的辨别能力均有增强；运动方向学习后，暴露的对比度、朝向和运动速率等刺激属性的辨别能力均有显著增强，表明运动方向在基于暴露知觉学习中具有独特性。在知觉辨别能力的增强效应方面，基于暴露所诱发的增强效应相对于有意识训练而诱发的增强效应依然较低，表明基于暴露知觉学习在提高知觉辨别方面仍有局限性。

基于上述研究结果，本研究提示，基于暴露知觉学习的发生与所暴露的刺激属性有关，这可能由于不同刺激属性在大脑中被处理的机制差异所造成；该学习效应无眼间特异性，这提示基于暴露的学习发生阶段不会早于V1；其学习效应可以长期保持；但其学习效应依然低于有意识参与的知觉学习所诱发效应，注意可以调控感觉信息处理能力的增益。本研究关于主动式知觉学习与基于暴露知觉学习的研究发现，是对双重可塑性模型的验证与扩展，深化了对知觉学习的理解。

In human cognitive activities, most of the input information is processed non-consciously. Perceptual learning (PL) is one of the most effective methods to enhance the processing of input sensory information. Perceptual learning typically focused on conscious information and active task and little is known about perceptual learning of non-conscious information processing. In the present study, we adopted a different-task of same-stimuli paradigm (DTSS), in which subjects were trained to discriminate one feature of a specifically-defined stimulus while ignoring all other task-irrelevant features, to systematically investigate the characteristics and rule of exposure-based perceptual learning (EBPL), aiming to broaden and deepen the understanding of perceptual learning.

Study I explored the effects of task-irrelevant features’ strength on global motion direction and global orientation discrimination learning. The experimental results showed that both the learning rate and magnitude of both tasks were not affected by strengths of task-irrelevant features, inconsistent with previous findings. In addition, exposure-based global orientation learning occurred after active motion direction training, which effect was also independent of the coherence levels of task-irrelevant features. However, exposure-based global motion direction learning was absent after intensive global orientation training under all exposure configurations. These results suggested that EBPL might involve different plasticity from active and conscious learning.

The purpose of study II was to further explore the characteristics of EBPL, covering the occurring requirements, inter-ocular specificity, retention of learning effect. We found that the occurrence of exposure-based global orientation learning was related to the task-irrelevant orientation configuration when having active global motion direction learning; the learning effect was similar between monocular and binocular training condition and can retain for at least 45 days. Similar to previou findings, exposure-based global motion learning did not happen after orientation discrimination training, no matter subjects were trained monocularly or binocularly.

Study III aimed to investigate the universality of EBPL in other features, including contrast, global orientation, motion direction, and motion speed. The experimental results showed that after training on features such as contrast, orientation and motion speed, performance improved on exposed features except for motion direction. By contrast, after motion direction learning, discrimination performances of all exposed features improved. These results indicated that motion direction might be a unique feature in EBPL. Moreover, the learning effect in EBPL was still lower than that induced by active perceptual learning, demonstrating limitation of EBPL in improving perceptual sensitivity.

Based on the above findings findings, the present study revealed both similar (e.g. longlasting, interocular transfer) and different (e.g. irrespective of exposed performance, not available for all features) plasticity characteristics of exposure-based perceptual learning. On the other hand, active training was still more effective in enhancing performance, showing the merits of attention and consciousness. The findings of active learning and exposure-based learning observed in the present study validated and extended the dual plasticity model and deepened the understanding of perceptual learning.