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.

Using Electroencephalogram-Extracted Nonlinear Complexity and Wavelet-Extracted Power Rhythm Features during the Performance of Demanding Cognitive Tasks (Aristotle’s Syllogisms) in Optimally Classifying Patients with Anorexia Nervosa

“…More specifically, the participants were exposed to three different sets of syllogisms (valid, invalid, and logical paradoxes), each one containing 39 syllogisms [ 1 , 21 ], as well as to a set of 39 optical illusions [ 93 ]. A further explanation of the types of syllogisms used in our study can be retrieved from previous works that followed different approaches using the same task [ 1 , 18 , 19 , 21 ].…”

“…Answers to each of the valid syllogisms are considered right if the subject considers them right, while answers to invalid syllogisms are considered right if the subject considers them wrong. Answers to paradoxical syllogisms depend on the subjective critical point of view, and therefore, the meaning of a wrong answer is not dogmatic [ 19 ]. Each subject’s answer is accompanied by the percent (%) of certainty given, which reflects the certainty in the answer provided.…”

“…The difference in EEG signals in healthy participants exposed to valid syllogisms and paradoxes has been analyzed before in the work of Papageorgiou et al [ 1 , 17 ] and Papaodysseus et al [ 18 ]. Recently, an fMRI study by Belekou et al [ 19 ] provided further evidence that valid and paradoxical reasoning engages distinct brain activation patterns. Finally, the work of Papaioannou et al [ 20 , 21 ] is very relative to this study since it has similar objectives, at least with respect to the reasoning strategies of subjects when they are exposed to Aristotelian syllogisms, yet with differences in the groups of subjects analyzed (ASD and ADHD) and the EEG extracted features used.…”