Central to Seidenberg and McClelland's (1989) parallel distributed processing (PDP) model's account of lexical decision is the assumption that performance is determined by the amount of overlap in the distribution of the orthographic error scores between words and nonwords. The present experiment demonstrates lexical decision performance that is independent of the distribution of orthographic error scores between words and nonwords. Furthermore, the orthographic error scores from the model capture no variance in the reaction time data to words, even in a condition in which the orthographic overlap between words and nonwords is minimal. Other issues are discussed.Until very recently there was a remarkable consensus in the visual word recognition literature regarding the nature of the underlying mental representation of words. It was widely assumed that words were stored as lexical entries in a mental lexicon, where each word was represented by an individual node (e.g.,

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In a letter identification task in which a centrallypresented letter is to be attended and laterally-flanking letters ignored, B.A. Eriksen and C.W. Eriksen (1974) have shown effects on performance of the to-be-ignored letters when they contain information about the correct response. These data constitute important evidence of late selection for attention on condition that the flankers are not, in fact, attended. Three experiments assess the importance of (1) practice on the task; (2) positional uncertainty regarding the flankers; (3) positional uncertainty regarding the target; (4) the proportion of flankers in a display which contain information about the response; and (5) the strength of the target-response mapping. The effect of flankers on performance is found to be independent of target position uncertainty and strength of target-reponse mapping, but to vary with practice on the task, flanker-position uncertainty, and proportion of informative flankers. The data are interpreted as indicating that people can adjust their strategy: They are capable of both early and late selection under different conditions.

H. Pashler (1984) reported that when subjects identified a probed letter in a display of 8 characters, the effect of stimulus quality on reaction time persisted full blown even when subjects had 300 ms to preprocess the display. Pashler argued that these results are incompatible with theories of late selection but that they are naturally accommodated by theories of early selection. The authors report 14 experiments using Pashler's methodology in which the effects of stimulus quality were reliably attenuated with a preview of the letter array. Pashler's results were also replicated, but only under a narrow set of conditions. Several "early selection" accounts of the interaction of probe delay with stimulus quality were examined and rejected in favor of a late selection account.

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