Recent reasoning accounts suggest that people can process elementary logical principles intuitively. These controversial “logical intuitions” are believed to result from a learning process in which developing reasoners automatize their application. To verify this automatization hypothesis, we contrasted the reasoning performance of younger (7th grade) and older (12th grade) reasoners with a two-response paradigm. Participants initially responded with the first intuitive response that came to mind and subsequently were allowed to deliberate on classic “bias” problems (base-rate problems and syllogisms). Results (...) showed that in addition to showing less deliberate correction of an initial erroneous response, younger reasoners were specifically less likely to generate the correct response from the outset. The findings lend credence to the role of a developmental automatization process and indicate that developmental improvements in reasoning accuracy are at least partially driven by an improvement in the accuracy of our intuitions. (shrink)

Abstract Introduction Logically valid deductive arguments are clear examples of abstract recursive computational proce‐ dures on propositions or on probabilities. However, it is not known if the cortical time‐consuming inferential pro‐ cesses in which logical arguments are eventually realized in the brain are in fact physically different from other kinds of inferential processes. Methods In order to determine whether an electrical EEG discernible pattern of logical deduction exists or not, a new experimental paradigm is proposed contrasting logically valid and invalid (...) inferences with exactly the same content (same premises and same relational variables) and distinct logical complexity (propositional truth‐functional operators). Electroencephalographic signals from 19 subjects (24.2 ± 3.3 years) were acquired in a two‐condition para‐ digm (100 trials for each condition). After the initial general analysis, a trial‐by‐trial approach in beta‐2 band allowed to uncover not only evoked but also phase asynchronous activity between trials. Results showed that (i) deductive inferences with the same content evoked the same response pattern in logically valid and invalid conditions, (ii) mean response time in logically valid inferences is 61.54% higher, (iii) logically valid inferences are subjected to an early (400 ms) and a late reprocessing (600 ms) verified by two distinct beta‐2 activa‐ tions (p‐value < 0,01, Wilcoxon signed rank test). Conclusion We found evidence of a subtle but measurable electrical trait of logical validity. Results put forward the hypothesis that some logically valid deductions are recursive or computational cortical events. Keywords Beta‐2 band, Evoked potentials, Induced potentials, Deductive inference, Logical validity, Cortical bases of logical reasoning. (shrink)