The relationship between deductive reasoning and the syntax of language in Broca's area: A review of the neuroimaging literature

A remarkable feature of the human brain is its ability to make deductions, that is, to infer valid conclusions from known information. In part because these deductions play an important role in spoken and written communication, it has been postulated that there is a close relationship between language and deductive reasoning in humans. Notably, some have proposed that deductive reasoning relies on a system of inferential rules that can be compared to the grammar of a natural language. Here I review the neuroimaging literature on deductive reasoning to evaluate whether there is some overlap between the neuro-cognitive operations that enable deduction and those that underlie the syntactic processing of language. Although some studies suggest that relatively simple deductions may involve Broca's area, no study to date has demonstrated that the mechanisms supporting the syntactic processing of language contribute to deductive reasoning. Implications for future directions in the literature are outlined.