Recent models of sentence context effects predict that the pattern of facilitation and inhibition of response to sentence completions should be influenced by the experiment-wide contextual "environment." In the present experiments, this environment was manipulated in several ways, including the degree to which contexts constrained possible completions, the probability of predictable completions' being presented, and the probability of congruous completions' being presented. In Experiment 1, decreasing the proportion of congruent test words had no effect on either the facilitation for highly likely words or the inhibition for incongruent words; increasing the proportion of predictable words produced no increase in facilitation for these words, but did increase the inhibition for incongruous words. In Experiment 2, contexts with very high or very low degrees of constraint produced equivalent results when predictability was uniformly low: no facilitation for unlikely but congruent words, and inhibition for incongruent words. In general, the patterns of change in facilitation and inhibition caused by changes in the contextual environment were more consistent with the modified two-process model (Stanovich & West, 1983) than with the verification model (Becker, 1982). But the limited range of influence suggests that, under conditions approximating normal reading, little use is made of such "metacontextual" information.
128It is not difficult to demonstrate that sentence contexts can influence performance on a variety of word processing tasks. But the mechanism of this influence, as well as its corresponding implications for theories of word retrieval and of reading, remains controversial. The present experiments concerned the extent to which a reader's expectancies can determine these context effects. Our approach was to vary systematically the information provided by sentence contexts at an "experiment-wide" level in several distinct ways. Recent models of the effects of verbal contexts make contrasting predictions about how changes in the contextual "environment" should influence the pattern of contextual effects.The basic paradigm involves presentation of an incomplete sentence context followed by a word that completes or continues the sentence. In most cases, some kind of neutral condition is used to separate context effects into facilitation-the advantage gained by presenting a test word that is congruous with the context-and inhibitionthe costs of incongruous test words. Schuberth and Eimas (1977) found both facilitation for congruous words and inhibition for incongruous words on lexical decision latency. Similar results were obtained by Fischler and Bloom (1979), who also showed that the amount of facilitation was positively related to the predictability of congruous words when predictability varied This research was reported in part at the meeting of the Midwestern Psychological Association, Detroit, May 1981. We are grateful to Keith Stanovich and an anonymous reviewer for their helpful comments on the manusc...