Fahle M
Department of Neuroophthalmology, University Eye Clinic, Tübingen, Germany.
Perception. 1994;23(4):411-27. doi: 10.1068/p230411.
A new theory of visual object recognition by Poggio et al that is based on multidimensional interpolation between stored templates requires fast, stimulus-specific learning in the visual cortex. Indeed, performance in a number of perceptual tasks improves as a result of practice. We distinguish between two phases of learning a vernier-acuity task, a fast one that takes place within less than 20 min and a slow phase that continues over 10 h of training and probably beyond. The improvement is specific for relatively 'simple' features, such as the orientation of the stimulus presented during training, for the position in the visual field, and for the eye through which learning occurred. Some of these results are simulated by means of a computer model that relies on object recognition by multidimensional interpolation between stored templates. Orientation specificity of learning is also found in a jump-displacement task. In a manner parallel to the improvement in performance, cortical potentials evoked by the jump displacement tend to decrease in latency and to increase in amplitude as a result of training. The distribution of potentials over the brain changes significantly as a result of repeated exposure to the same stimulus. The results both of psychophysical and of electrophysiological experiments indicate that some form of perceptual learning might occur very early during cortical information processing. The hypothesis that vernier breaks are detected 'early' during pattern recognition is supported by the fact that reaction times for the detection of verniers depend hardly at all on the number of stimuli presented simultaneously. Hence, vernier breaks can be detected in parallel at different locations in the visual field, indicating that deviation from straightness is an elementary feature for visual pattern recognition in humans that is detected at an early stage of pattern recognition. Several results obtained during the last few years are reviewed, some new results are presented, and all these results are discussed with regard to their implications for models of pattern recognition.
波吉奥等人提出的一种基于存储模板之间多维插值的视觉对象识别新理论，要求视觉皮层进行快速的、特定于刺激的学习。事实上，通过练习，许多感知任务的表现都会得到改善。我们区分了学习游标视力任务的两个阶段，一个快速阶段在不到20分钟内完成，一个缓慢阶段在超过10小时的训练过程中持续，可能还会更长。这种改善特定于相对“简单”的特征，例如训练期间呈现刺激的方向、视野中的位置以及学习所通过的眼睛。其中一些结果通过一个计算机模型进行了模拟，该模型依赖于通过存储模板之间的多维插值进行对象识别。在跳跃位移任务中也发现了学习的方向特异性。与表现的改善方式类似，跳跃位移诱发的皮层电位在训练后潜伏期往往缩短，幅度往往增大。由于反复接触相同刺激，大脑上电位的分布会发生显著变化。心理物理学和电生理学实验的结果均表明，某种形式的感知学习可能在皮层信息处理的早期就会发生。游标断点在模式识别过程中“早期”被检测到这一假设得到了以下事实的支持，即检测游标的反应时间几乎完全不依赖于同时呈现的刺激数量。因此，游标断点可以在视野的不同位置并行检测，这表明直线度偏差是人类视觉模式识别的一个基本特征，在模式识别的早期阶段就会被检测到。本文回顾了过去几年获得的一些结果，展示了一些新结果，并就这些结果对模式识别模型的影响进行了讨论。
