Paradoxical Reasoning: An fMRI Study

Abstract

Paradoxes are a special form of reasoning leading to absurd inferences in contrast to logical reasoning that is used to reach valid conclusions. A functional MRI (fMRI) study was conducted to investigate the neural substrates of paradoxical and deductive reasoning. Twenty-four healthy participants were scanned using fMRI, while they engaged in reasoning tasks based on arguments, which were either Zeno's like paradoxes (paradoxical reasoning) or Aristotelian arguments (deductive reasoning). Clusters of significant activation for paradoxical reasoning were located in bilateral inferior frontal and middle temporal gyrus. Clusters of significant activation for deductive reasoning were located in bilateral superior and inferior parietal lobe, precuneus, and inferior frontal gyrus. These results confirmed that different brain activation patterns are engaged for paradoxical vs. deductive reasoning providing a basis for future studies on human physiological as well as pathological reasoning.

Keywords: deductive reasoning; fMRI; fronto-parietal brain activation patterns; fronto-temporal brain activation patterns; paradoxical syllogism.

Figure 1

This figure presents the neuroimaging results of the comparison of reasoning trials to the control task: (A) activation maps of areas that were significantly more activated during paradoxical reasoning compared to the control task; (B) activation maps of areas that were significantly more activated during deductive reasoning for valid syllogisms compared to the control task; and (C) activation maps of areas that were significantly more activated during deductive reasoning for invalid syllogisms compared to the control task.

Figure 2

This figure presents the neuroimaging results of the comparison between deductive reasoning and paradoxical reasoning trials: (A) activation maps of areas that were differentially activated between deductive reasoning for valid syllogisms and paradoxical reasoning trials. Cyan color marks the areas that were more active for deductive valid reasoning compared to paradoxical reasoning while violet marks the areas that were more active for paradoxical reasoning compared to deductive valid reasoning. (B) Activation maps of areas that were differentially activated between deductive reasoning for invalid syllogisms and paradoxical reasoning trials. Blue color marks the areas that were more active for deductive invalid reasoning compared to paradoxical reasoning while violet marks the areas that were more active for paradoxical reasoning compared to deductive invalid reasoning.