DIRECTING ATTENTION TO WORDS AND NONWORDS IN NORMAL SUBJECTS AND IN A COMPUTATIONAL MODEL - IMPLICATIONS FOR NEGLECT DYSLEXIA

In a previous paper, we proposed that patients with neglect dyslexia process information appearing on the unattended side. This information, if encoded sufficiently, may be used to trigger top-down knowledge, leading to the interaction of spatial attention and lexicality. The current studies examine this question in normal people. Subjects' attention was biased to the end of a letter string by a cue (underline bar) and lexical decisions were made to the underlined section of the letter string (for example, east and garm). These studies showed that reaction times were slower when distracting information appeared on the left than when no distractors were present (for example, arm). Furthermore, when the distractors played a lexical role and formed a word with the underlined string (for example, farm), lexical decisions were even slower. These results showed that distractors are processed at least to the level of lexical access and influence reading performance of the attended underlined string. We have also considered these findings in the light of an existing connectionist network of spatial attention and word recognition and have accounted for the data in a series of simulations. The convergence of findings from the neuropsychological, cognitive, and computational work supports the interaction between attention and higher-order lexical knowledge.