Bock, M. & Milz, B. (1977). Pictorial context and the recall of pronoun sentences. Psychological Research, 39, 203-220.
Acting on the assumption that pictures affect the processing of sentences only when providing additional information, the authors used pictures, which in an earlier experiment had failed to influence the retention of noun sentences, as illustrations to semantically undefined pronoun sentences, thus establishing a distinct information gradient between sentence and picture. These pronoun sentences were presented to 48 subjects for recall, in four pictorial conditions: without picture, with unambiguous picture, with subject-ambiguous, and with object-ambiguous picture. As hypothesized, picture-less pronoun sentences were more poorly recalled than picture-enriched pronoun sentences. Moreover, sentences accompanied by subject-ambiguous pictures, in which the grammatical subject could not be clearly identified, scored lower than the same sentences with unambiguous or object-ambiguous pictures. The findings invite a communication-theory analysis of the experimental situation, for which Searle's theory of speech acts is invoked.