A neuropsychological theory is offered to account for the syndrome of Broca's aphasia. A critical review of the literature, with emphasis on recent research, provides the basis for a redefinition of the syndrome that considerably broadens its classical description. The argument is advanced that the focus of neuropsychological explanation should be on theoretically separable psychological mechanisms that might be disrupted in relative isolation from other components in conditions of focal brain damage, rather than on isolated units of aphasic performance. The symptoms that characterize Broca's aphasia are explained as predictable behavioral manifestations of a central disruption of the syntactic parsing component of the language System, coupled with a (theoretically independent) articulatory deficit that affects only the speech output System. The neuroanatomical implications of this argument are considered within the framework of the classical “strong localizationist” hypothesis.

We have compared the verbal comprehension abilities of 34 right hemisphere damaged patients to 16 hospitalized control subjects of comparable age and educational attainment. The right hemisphere damaged patients performed as well as the control subjects on a vocabulary test, but were impaired in their ability to interpret proverbs and comprehend logico-grammatical sentences. Impairment on the proverbs test was the result of a decrease in the number of abstract interpretations, whereas impairment on the logico-grammatical sentence comprehension test was related to difficultes in grasping spatial and passive relationships. These comprehension impairments tended to correlate with visuospatial deficits and hemianopia, but not with the degree of hemiparesis or the presence of sensory extinction. Patients with anterior right hemisphere damage performed better on the logico-grammatical sentence conprehension test than patients with posterior damage. A variety of factors probably contribute to these verbal deficits including impaired intellect, inattention, an inability to grasp spatial relationships, and difficulties in manipulating the inner schemata of language.

Language disordered children's responses to sentences that can carry directive import were examined under varying contextual conditions. In the first experiment, sentences were presented in a neutral context; in the second experiment, two different kinds of sentences provided linguistic contexts for test sentences. Taken together, the results of the studies indicate that language disordered children are qualitatively much like normal children with regard to early response behavior. They show evidence of an early action response strategy and some ability to take context into account. On the other hand, they do appear to have more difficulty both in generating informing responses and in utilizing information from prior linguistic context. A possible reason for this latter deficit is suggested.

A method was tested for teaching people how to identify implied claims in advertising and keep from remembering them as asserted facts. The experimental group received a detailed training session, while the control group participated in a comparable session not dealing with implied claims. Subjects then heard a series of ads with critical claims either asserted or implied and rated a set of claims for their truth value. Results showed that, when subjects heard the same ads two, seven, and nine days later, they increasingly recognized that implied claims were implied and rated them less true than directly asserted claims. Results were related to previous research and consumer education.