Cognitive Neuroscience of Deductive Reasoning

It is 4pm and I hear the school bus pull up to the house. Soon there is the taunting of a 13-year-old boy followed by the exaggerated screams of an 8-year-old girl. My kids are home from school. Exasperated, I say to my son, " If you want dinner tonight, you better stop tormenting your sister. " Given he doesn't want to go to bed hungry, he needs to draw the correct logical inference. Sure enough, peace is eventually restored. Notice that he was not explicitly told to stop tormenting his sister. Yet we are not surprised by his actions. His behavior is not a mystery (assuming he wants his dinner). It is just an example of the reasoning brain at work. Reasoning is the cognitive activity of drawing inferences from given information. All reasoning involves the claim that one or more propositions (the premises) provide some grounds for accepting another proposition (the conclusion). The above example involves a deductive inference (see Evans, this volume). A key feature of deduction is that conclusions are contained within the premises and are logically independent of the content of the propositions. Deductive arguments can be evaluated for validity, a relationship between premises and conclusion involving the claim that the premises provide absolute grounds for accepting the conclusion (i.e. if the premises are true, then the conclusion must be true). Two theories of deductive reasoning (mental logic and mental models) dominate the cognitive literature. They differ with respect to the competence knowledge they draw upon, the mental representations they postulate, the mechanisms they invoke, and the neuroanatomical predictions they make. Goel 3 of 38 that Reasoners have an underlying competence knowledge of the inferential role of the closed-form, or logical terms, of the language (e.g. 'all', 'some', 'none', 'and', etc,). The internal representation of arguments preserve the structural properties of the propositional strings in which the premises are stated. A mechanism of inference is applied to these representations to draw conclusions from premises. Essentially, the claim is that deductive reasoning is a rule governed process defined over syntactic strings. 1 and use this knowledge to construct and search alternative scenarios. 2 The internal representation of arguments preserve the structural properties of the world (e.g. spatial relations) that the propositional string are about rather than the structural properties of the propositional strings themselves. The basic claim is that deductive reasoning is a process requiring spatial …