They ask the question of whether heuristics processes can build meaning without the need of algorithmic procedures.
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What prediction(s) does the hypothesis being tested make?
Hypothesis: Broca’s aphasics no longer fully control algorithmic processes, which are likely to operate independently from semantic content.
Prediction: Broca’s should have problems processing reversible center-embedded sentences.
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Linguistic: They include three bypes of center embedded sentences and a control sentence that does not contain a relative pronoun.
Neurological: Three types of participants with different brain lesions: Broca, Wernicke and Conduction.
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Four linguistic constructions are tested. What are they? What does each contribute to the exploration of the question? (Why do they use these constructions?)
They are as follows:
1. nonreversible center-embedded sentences
2. reversible center-embedded sentences
3. improbable center-embedded sentences
4. control sentences. They are similar to sentences in other conditions in that they are composed of two (underlying) simple sentences.
The interpretation of reversible center-embedded sentences relies on algorithmic processing. For example, in the sentence “the boy that the girls is chasing is tall”, the claim is that both nouns “boy” and “girl” can be agents and patients of the sentence. Which role each noun plays depends on their position in the sentence.
Heuristic processes are instantiated with nonreversible center-embedded sentence such as “the apple that the boy is eating is red”. In this sentence, regardless of the position in the sentence, it is clear that the agent must be the animate noun “boy”, whereas the theme is the “apple”. Thus the meaning of the noun is indicative of the role it plays in the sentence.
Improbable sentences contain violations of world knowledge as in the sentence “the boy that the dog is patting is fat”. In this case, the world knowledge indicates that the most likely situation is that the boy is patting the dog, and not the inverse situation.
The control condition does not contain a relative pronoun.
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Mean number of correct responses.
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The authors’ conclusion is that Broca’s patients are impaired in both comprehension and production. The impairment, however, is specific to the processing of syntactic information (algorithmic processing). They seem to use semantic information (heuristics) to guide their comprehension and production. Thus they conclude that Broca’s area subserves syntactic processing.
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