Routes to reading: a report of a non-semantic reader with equivalent performance on regular and exception words.

This study reports the case of a stroke patient, EW, who had severely-impaired comprehension of written words but could read aloud regular and exception words, non-words and sentences flawlessly. EW's auditory comprehension was also impaired. It is argued that these results support a three-route model of reading, where the phonological output lexicon can be activated directly from the orthographic input lexicon, as her reading performance did not conform to the pattern that would be expected from a combination of lexical-semantic and sublexical processing alone. It is suggested that normal reading may be better conceptualised as a summation of three routes, rather than two.

Age-of-acquisition and frequency effects in speeded word naming.

An experiment was conducted to assess the importance of age-of-acquisition and frequency in a speeded word naming task, where participants were instructed to read aloud words before they disappeared from the computer screen. Under such speeded naming instructions, reading latencies were over 100ms (or 20%) faster than in "standard" (or immediate) word naming. There were clear effects of word frequency and age-of-acquisition under speeded naming. Compared to standard immediate naming, the age-of-acquisition effect was larger, with early-acquired words being speeded up more than late-acquired words, which is interpreted in terms of speeded naming reducing the contribution of sublexical processing to word naming times.

Re-evaluating age-of-acquisition effects: are they simply cumulative-frequency effects?

The time it takes to read or produce a word is influenced by the word's age of acquisition (AoA) and its frequency (e.g. Quarterly Journal of Experimental Psychology 12 (1973) 85). Lewis (Cognition 71 (1999) B23) suggested that a parsimonious explanation would be that it is the total number of times a word has been encountered that predicts reaction times. Such a cumulative-frequency hypothesis, however, has always been rejected because the statistical effects of AoA and frequency are additive. Here, it is demonstrated mathematically that the cumulative-frequency hypothesis actually predicts such results when applied to curvilinear learning. Further, the data from four influential studies (two of which claim support for independent effects of AoA and frequency) are re-analyzed to reveal that, in fact, they are consistent with a cumulative-frequency hypothesis. The conclusion drawn is that there is no evidence with which to refute the most parsimonious of explanations, i.e. cumulative frequency can account for both frequency and AoA effects.

When does a deep dyslexic make a semantic error? The roles of age-of-acquisition, concreteness, and frequency.

Semantic reading errors are the central and defining feature of deep dyslexia. This study compared the words the deep dyslexic patient LW read correctly with those she omitted and those to which she produced semantic errors in terms of their concreteness, age-of-acquisition, frequency, and length. Semantic errors were made to less concrete, later-acquired, and shorter words than were read correctly; there was no reliable effect of word frequency. More importantly, the actual semantic errors produced were later-acquired than the stimulus words, but they were not more concrete or reliably more frequent. These results implicate age-of-acquisition in the process that produces semantic errors. It is proposed that concreteness determines the specificity of the semantic system to activate a set of candidate responses and that age-of-acquisition biases the ease with which certain words can be selected from this set to be produced as reading responses.

A 29-year-old female with progressive myoclonus and cognitive decline.

Myoclonic epilepsy with red ragged fibres (MERRF) is a rare mitochondrial disorder presenting with progressive myoclonus, epilepsy, and cognitive decline. Here, the authors present a case of a 29-year-old lady presenting with myoclonus and describe the subsequent investigations that led to a diagnosis of MERRF. In addition, we examine her cognitive decline over a 9-year period, demonstrating a feature commonly seen in mitochondrial cytopathies.

Age of acquisition, word frequency, and the role of phonology in the lexical decision task.

In five experiments, we examined the respective roles of word age of acquisition (AoA) and frequency in the lexical decision task. The two variables were manipulated orthogonally (while controlling for concreteness and length) in fully factorial designs. Experiment 1 was a conventional lexical decision task, and Experiments 2-5 involved various attempts to interfere with reliance upon phonology. In Experiment 2, only orthographically illegal nonwords were used; in Experiment 3, pseudohomophone nonwords; in Experiment 4, articulatory suppression by the recitation of a nursery rhyme; and in Experiment 5, articulatory suppression by the repetition of a single word. The same basic pattern of results was observed in all experiments: There were main effects of both AoA and frequency, which interacted in such a way that the AoA effect was larger for low- than for high-frequency words. Although the AoA effect was reduced by manipulations intended to interfere with phonological processing, the manipulations did not eliminate the effect. The results are discussed in terms of current models of reading in which it is proposed that AoA has its primary effect on the retrieval of lexical phonology, which appears to be consulted automatically in the lexical decision task.