Encoding and contextual components of word recognition in good and poor readers

Good and poor readers from the third and sixth grades (9- and 12-year-olds, respectively), named visually presented words as rapidly as possible. Words were in clear or degraded form, and were preceded by related or unrelated words. Poor readers were hurt more by degradation than were good readers, and showed greater benefit from context. In general, the contextual benefit was greater with degraded words than with intact, and this interaction was especially pronounced in the poor readers. The results are consistent with an interactive-compensatory model of word recognition. Under conditions in which stimulus encoding is slow, contextual factors may compensate for this encoding deficit.     

Event-related brain potentials elicited during word recognition by adult good and poor phonological decoders

Cognitive processing of lexical and sub-lexical stimuli was compared for good and poor adult phonological decoders. Sixteen good decoders and 16 poor decoders, average age 19 years, silently read 150 randomly computer presented sentences ending in incongruous regular, irregular, or nonwords and 100 congruent filler sentences. Electro-encephalographic recordings were made from the final word of each incongruous sentence. Although no significant group differences were found, good decoders showed specialised hemispheric word recognition processing at P200 and P300. Nonwords elicited greater N200 and P300 amplitudes for both good and poor decoders. Larger amplitude P200s were elicited by poor decoders when processing nonwords. These findings provide evidence for separable lexical and sub-lexical procedures and support a psychophysiological basis for a core phonological deficit in poor phonological decoders.     

Assessing the role of different spatial frequencies in word perception by good and poor readers

Numerous studies indicate that dyslexic and nondyslexic individuals exhibit different patterns of sensitivity to spatial frequency. However, the extension of this effect to normal (nondyslexic) adults of good and poor reading abilities and the role played by different spatial frequencies in word perception have yet to be determined. In this study, using normal (nondyslexic) adults, we assessed reading ability, spatial frequency sensitivity, and perception of spatially filtered words and nonwords (using a two-alternative forced choice paradigm to avoid artifactual influences of nonperceptual guesswork). Good and poor readers showed different patterns of spatial frequency sensitivity. However, no differences in accuracy of word and nonword perception were found between good and poor readers, despite their differences in spatial frequency sensitivity. Indeed, both reading abilities showed the same superior perceptibility for spatially filtered words over nonwords across different spatial frequency bands. These findings indicate that spatial frequency sensitivity differences extend to normal (nondyslexic) adult readers and that a range of spatial frequencies can be used for word perception by good and poor readers. However, spatial frequency sensitivity may not accurately reveal an individual's ability to perceive words.     

The effect of orthographic structure on the word search performance of good and poor readers.

Good and poor third-grade readers searched for target words through fields consisting of words, pseudowords, and nonwords. Both groups searched faster through nonword fields than pseudoword fields and faster through pseudoword fields than word fields. The better readers did not show larger orthographic structure effects. In fact, both speed and accuracy performance measures tended to indicate a greater sensitivity to orthographic structure on the part of the poorer readers. It is argued that the results are better accounted for by compensatory rather than serial stage models of the organization of the component subskills of reading.     

Continued word associations and free recall

Two experiments on the short-term free recall of 12-word associated and non-associated lists are reported. Degree of association (derived from norms obtained by continuous controlled association) and word frequency were varied. Significant facilitation as a result of the associative manipulations was obtained and clustering of the responses was positively related to this. Clustering was also affected by the method of presentation of the associated words; this occurred more often when they were grouped in presentation than when they were presented randomly arranged among other words in the list. Low frequency associated word lists were generally found to be more efficiently recalled than those of comparable association values but consisting of high frequency words.     

Valence, arousal and word associations

This study aimed at testing the relative effects of valence and arousal on the generation of unusual first associates in response to non-emotional inducers. To examine this question, four specific moods varying along both the valence and the arousal dimensions were induced: happiness (positive mood, high arousal), serenity (positive mood, low arousal), anger (negative mood, high arousal) and sadness (negative mood, low arousal). The results indicate that the uniqueness of word-associations is influenced by arousal levels rather than by the valence of mood. No matter what the valence, high-arousing moods enhanced the production of unusual associates in contrast to low-arousing moods.     

Altered patterns of word associations in dementia and aphasia

The word associations of 38 demented, 17 aphasic, and 22 normal subjects were studied. Both normal and brain-injured subjects appear to make judgments about the grammatical class of the word stimulus. Certain stimulus words (especially nouns and adjectives) elicit paradigmatic responses whereas other words (especially verbs and adverbs) elicit syntagmatic responses. The mechanism producing syntagmatic responses seems relatively resistant to deterioration in dementia or aphasia. However, in dementia the mechanism that generates paradigmatic responses becomes progressively less efficient (possibly due to a loss of semantic markers) and consequently more random (idiosyncratic) responses emerge. Perseverative responses, inhibited in normal subjects, are more prevalent in dementia. Anomic aphasics show a pattern of word associations similar to that of subjects with mild dementia. Broca's aphasics, while making fewer paradigmatic associations than normals, retain enough self-monitoring mechanisms so that few idiosyncratic and perseverative responses are made while more null responses occur. Wernicke's aphasics show a marked shift away from a paradigmatic word association strategy, possibly due to an inability to access semantic markers or a true loss of these markers. Metalinguistic deficits (i.e., a failure to adopt an appropriate strategy) may also contribute to this shift away from paradigmatic associations. Furthermore, a disruption of self-monitoring mechanisms in Wernicke's aphasia leads to an increase in perseverative and idiosyncratic responses.     

Proofreading errors in good and poor readers

Seven-year-old children classified as good and poor readers carried out a proofreading task on two passages varying in level of difficulty. Misspellings were introduced by transposing two adjacent letters in the work "the," other three-letter words, and longer words. While both groups of readers were able to identify the correct spelling of the misspelled words on a spelling test, poor readers made significantly more proofreading errors. Word length had a significant effect on performance, indicating that sensitivity to word configuration is important for successful proofreading. The pattern of proofreading errors did not reflect underlying differences which might relate to strategies used by the two groups in normal reading. The results are compared with those from other proofreading and letter detection experiments in order to highlight methodological implications when such tasks are used to verify hypotheses concerned with normal reading strategies.