Движения глаз в ходе спонтанного и контролируемого обнаружения слов в больших буквенных массивах
The aim of this study was to analyze the scope and limitations of top-down influences upon visual information processing (during visual search for letters and words in random letter arrays). Previously we have demonstrated that the presence of words in large letter arrays does not affect the efficiency of visual search for a target letter in these arrays. The current study shows that spontaneous word extraction during visual search for target letters and controlled word extraction during visual search for words are mediated by different perceptual strategies. Spontaneous word detection is not accompanied by specific eye movements, whereas the words search task produces an increase of the number of eye fixations over all the letter array, both within and between words. In an additional study we demonstrate that categorical set does not affect the efficiency of visual search for words in random letter arrays: it seems that observers first extract words from letter arrays and then categorize detected words. Thus, there appears to exist two distinct mechanisms providing for the detection of words in letter arrays. The first mechanism is based on the processing of separate letters, whereas the second one is based on the processing of words as perceptual chunks.