Semantic facilitation and lexical access during sentence processing: An investigation of individual differences

An earlier experiment (Blank & Foss, 1978) showed that the time required to access the object noun of a sentence was shortened if the noun was preceded by a semantically related verb or adjective. When both the verb and the adjective were semantically related to the noun, the amount of facilitation of lexical access was additive. However, additivity appeared to break down for subjects who did poorly on the comprehension test administered in that experiment, suggesting that the activation function among related lexical items was different for good and poor comprehenders. Such a finding would have implications for theories of lexical facilitation, especially the two-factor theories such as the one proposed by Posner and Snyder (1975). The present experiment again measured access time for the object noun of a sentence when it was preceded by an unrelated or a related verb or adjective (four sentence types). Two groups of college subjects were tested, relatively good (N = 63) and relatively poor (N = 42) comprehenders. The difference in the time taken to retrieve the object noun was ascertained by measuring reaction time to respond to the initial phoneme of the next word in the sentence (phoneme monitoring technique). Reaction times were shorter when the noun was preceded by a semantically related word; the effects of two sources of related context (verb and adjective) appeared to be additive forboth groups of subjects. These results were discussed within the context of two-factor theories of lexical activation and within the context of Morton’s (1969) logogen model.