Semantic facilitation and lexical access during sentence processing

An experiment was conducted testing predictions derived from context-dependent and context-independent models of lexical access. Four types of unambiguous test sentences were constructed. The direct object of each test sentence was preceded by a verb that was either semantically related or unrelated to it, and by an adjective that was semantically related or unrelated. Context-dependent models predict that the speed with which the object noun is retrieved from the mental lexicon will be faster when the verb and/or the adjective is semantically related; context-independent models predict no such facilitation. Forty-four subjects each heard 32 test sentences and were asked to monitor within the sentence for a word-initial target phoneme. The target phoneme occurred on the word following the object noun. Reaction times to detect the targets were obtained. According to context-dependent models, these times should be shorter when related words precede the object noun, and that is what was found. It was also observed that the facilitation effects due to the related verbs and adjectives were additive. Implications of these results were discussed.