Sequential and parallel letter processing in letter-by-letter dyslexia
Sequential and parallel letter processing in letter-by-letter dyslexia
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DOI：
10.1080/02643290244000040
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发表时间：
2002-09-01
影响因子：
3.4
通讯作者：
Bub, D
中科院分区：
文献类型：
--
作者：
Arguin, M;Fiset, S;Bub, D
本文报道了四个实验，重点研究了逐字阅读障碍（LBL）中顺序与平行字母加工的问题；这些是在患者IH上进行的。实验1显示，单词命名时间随着目标正字法邻居数量的增加而大幅线性减少（即相同长度的单词仅相差一个字母；N大小）。鉴于单词长度与N大小之间存在较大的负线性相关，这一结果提出了一种可能性，即LBL阅读障碍的大单词长度效应诊断实际上可能是一个不受控制的N大小的人工产物。exp . 2通过证明单词长度效应不受是否控制N大小的影响而证明了这种可能性。这一结果也表明，增加的N大小对LBL阅读障碍的促进作用是基于对目标组成字母的平行加工。进一步支持平行字母处理对障碍中显性单词识别性能的贡献，实验3显示了单词长度和字母混淆性（即目标单词的组成字母与字母表中其他字母的相似性）的显著但独立的影响。因此，字母混淆效应似乎取决于对目标单词中字母的平行分析。最后，实验4表明，高字母混淆度的目标会阻碍N大小的促进效应。这些观察结果表明，LBL阅读障碍取决于字母编码的损伤，当字母被并行处理时，在激活词汇正字法表征时，会导致过量的背景噪音。这可以防止目标的明显识别，并强制顺序字母处理，以实现这一目标。
Four experiments are reported that focus on the issue of sequential vs. parallel letter processing in letter-by- letter (LBL) dyslexia; these were conducted on patient IH. Expt. 1 showed a large linear reduction of word naming times with an increase in the number of orthographic neighbours of the target (i. e., words of the same length differing by just one letter; N size). Given the large negative linear correlation existing between word length and N size, this result raises the possibility that the large word length effect diagnostic of LBL dyslexia may be, in fact, an artefact of uncontrolled N size. Expt. 2 falsified this possibility by showing that the word length effect is unaffected by whether N size is controlled for or not. This result also suggested that the facilitatory effect of increased N size in LBL dyslexia is based on the parallel processing of the constituent letters of the target. Further supporting a contribution of parallel letter processing to overt word recognition performance in the disorder, Expt. 3 showed significant but independent effects of word length and letter confusability (i. e., similarity of the constituent letters of the target word with other letters of the alphabet). The letter confusability effect therefore appears to rest on the parallel analysis of the letters in the target word. Finally, Expt. 4 showed that the facilitatory effect of N size is prevented with high letter- confusability targets. These observations suggest that LBL dyslexia rests on an impairment of letter encoding that results in an excessive level of background noise in the activation of lexical- orthographic representations when letters are processed in parallel. This prevents overt identification of the target and forces sequential letter processing in order to achieve this goal.