P3a amplitude is related to conclusion specificity during category-based induction

Abstract

Category-based induction involves the generalization of a novel property (conclusion property) to a new category (conclusion category), based on the knowledge that a category exemplar (premise category) has the respective novel property. Previous studies have shown that conclusion specificity (i.e., specific [S] or generic categories [G]) influences category-based induction. However, the timing of brain activity underlying this effect is not well known, especially with controlling the similarities of premise and conclusion categories between S and G arguments. In this study, the event-related potential (ERP) responses to category-based induction between S and G arguments were compared under both congruent (+, premise and conclusion categories are related) and incongruent (-, premise and conclusion categories are unrelated) arguments; additionally, the similarities of premise and conclusion categories between S and G arguments were controlled. The results showed that replicating this effect, S+ arguments have increased "strong" response rates compared to G+ arguments, suggesting that category-based induction is contingent on factors beyond matched similarities. Moreover, S arguments have more liberal inductive decision thresholds than G arguments, which suggest that conclusion specificity affects the inductive decision reflected by inductive decision thresholds. Furthermore, G+ arguments elicit greater P3a amplitudes than S+ arguments, which suggest greater attention resources allocation to the review of decisions for G+ arguments than that for S+ arguments. Taken together, the conclusion specificity effect during semantic category-based induction can be revealed by "strong" response rates, inductive decision thresholds, and P3a component after controlling the premise-conclusion similarity, providing evidence that category-based induction rely on more than simple similarity judgment and conclusion specificity would affect category-based induction.

Fig 1. The experimental procedure.

Fig 2. The “strong” response rates, reaction times, and inductive decision thresholds for each kind of arguments.

S+ indicated arguments with specific congruent conclusion categories; G+ indicated arguments with generic congruent conclusion categories; S− indicated arguments with specific incongruent conclusion categories; and G− indicated arguments with generic incongruent conclusion categories. Error bars represent mean ± S.E.M. ***p < 0.001.

Fig 3. P3a amplitudes to the effect of conclusion specificity in the congruent and incongruent conclusions.

A) The grand-averaged waveforms elicited by G+ and S+ arguments and the difference waveforms between G+ and S+ arguments (G+ minus S+) in the anterior and posterior regions; and the grand-averaged waveforms elicited by G− and S− arguments and the difference waveforms between G− and S− arguments (G− minus S−) in the anterior and posterior regions. B) The topographies of the difference waveforms at 250–450-ms time window (G+ minus S+); and the topographies of the difference waveforms at 250–450-ms time window (G− minus S−). C) P3a amplitudes for each kind of arguments. The anterior region indicates the mean amplitudes of F3, F1, Fz, F2, F4, FC3, FC1, FCz, FC2, and FC4 electrodes; the posterior region indicates the mean amplitudes of CP3, CP1, CPz, CP2, CP4, P3, P1, Pz, P2, and P4 electrodes. S+ indicated arguments with specific congruent conclusion categories; G+ indicated arguments with generic congruent conclusion categories; S− indicated arguments with specific incongruent conclusion categories, and G− indicated arguments with generic incongruent conclusion categories.

Fig 4. Pearson correlation analysis between the difference of P3a amplitudes (G+ minus S+) and the difference of “strong” response rates (G+ minus S+).

S+ indicated arguments with specific congruent conclusion categories; G+ indicated arguments with generic congruent conclusion categories.