Huckauf Anke, Nazir Tatjana A
Bauhaus-University Weimar, Germany.
J Vis. 2007 Aug 16;7(2):18.1-12. doi: 10.1167/7.2.18.
Processes underlying crowding in visual letter recognition were examined by investigating effects of training. Experiment 1 revealed that training reduces crowding mainly for trained strings. This was corroborated in Experiment 2, where no training effects were obvious after 3 days of training when strings changed from trial to trial. Experiment 3 specified that after a short amount of training, learning effects remained specific to trained strings and also to the trained retinal eccentricity and the interletter spacing used in training. Transfer to other than trained conditions was observed only after further training. Experiment 4 showed that transfer occurred earlier when words were used as stimuli. These results thus demonstrate that part of crowding results from the absence of higher level representations of the stimulus. Such representations can be acquired through learning visual properties of the stimulus.
通过研究训练的效果，对视觉字母识别中拥挤现象背后的过程进行了考察。实验1表明，训练主要减少了对经过训练的字符串的拥挤现象。实验2证实了这一点，当字符串在每次试验中都发生变化时，经过3天的训练后没有明显的训练效果。实验3明确指出，经过少量训练后，学习效果仍然只针对经过训练的字符串，以及训练时所使用的视网膜离心率和字母间距。只有在进一步训练后，才观察到向非训练条件的迁移。实验4表明，当使用单词作为刺激时，迁移出现得更早。因此，这些结果表明，拥挤现象的一部分是由于缺乏刺激的高级表征所致。这样的表征可以通过学习刺激的视觉属性来获得。
