Event-Related Potential Parameters Related To Premise Monotonicity Effects During Category-Based Induction

Inductive reasoning refers to make predictions about novel objects or situations based on existing knowledge.Category-based induction involves applying knowledge of categorical relations to generalize a novel property from one or a set of categories to a conclusion category,playing an essential role in category learning and use.The premise monotonicity effect/the sample size effect during category-based induction is a robust effect that occurs when generalization of a novel property shared by many cases is more likely than one shared by few cases.Previous studies have explored the behavioral characteristics of this effect,however,the timing of brain activity during the premise monotonicity effect is unclear.Therefore,three experimental researches were performed to explore the event-related potentials responses(ERPs)for the premise monotonicity effect during semantic category-based induction based on binary responses(accept vs.reject or strong vs.weak)and 4-point Likert Scale.Moreover,behavioral research was used to explore the behavioral differences between category-based induction and categorization,so as to further prove the validity of the research results.In the first study,the ERP features underpinning the premise monotonicity effect were measured by manipulating the premise sample size(single [S] vs.two [T])in a semantic category-based induction task,with the conclusion categories either including the premise categories(congruent induction [+])or not(incongruent induction [-]).Participants were required to infer the inductive strength of the conclusions based on the premise(s)with binary responses(accept vs.reject or strong vs.weak).The behavioral results replicated the premise monotonicity effect: S arguments produced lower “correct” rates than did T arguments,and revealed that S arguments produced longer reaction times than did T arguments.ERP results demonstrated that the premise monotonicity effect was reflected by two parameters during inductive decision:(1)S arguments elicited larger FN400 amplitudes than did T arguments(250–450-ms),and(2)S arguments elicited larger sustained negativity(SN)in the 450–650-ms time window than did T arguments.On the basis of the first study,the second study modified slightly the experimental procedure: Participants were required to infer the inductive strength of the conclusions based on the premise(s)with 4-point Likert Scale.The behavioral results largely replicated the first study: S arguments had less “definite” responses(possibly weak or possibly strong),lower “correct” response rates,and longer reaction times than those of T arguments.Moreover,S arguments produced more conservative response criteria than did T arguments.Furthermore,the ERP results also found similar results to the first study:(1)S arguments elicited larger FN400(250–450-ms)amplitudes than did T arguments under congruent induction;(2)S arguments elicited larger SN amplitudes in the 450–1050-ms time window than did T arguments under both congruent induction and incongruent induction.In the third study,participants were instructed to decide whether all premise categories belonged to the conclusion categories,with responses based on a 4-point Likert Scale,using the similar experimental procedure to the second study.The behavioral results showed that more “definite” responses(definitely weak or definitely strong)and more short reaction times in the categorization task than in the induction task for S+ arguments,S-arguments,and T-arguments.However,the response strength and the reaction times were not significant differences between categorization task and induction task for T+ arguments.And the “correct” response rates were also not significant differences between categorization task and induction task for all sub-conditions.Collectively,the results revealed significant differences between category-based induction and categorization for all sub-conditions except for T+ arguments.Results of the three studies consistently showed that,during category-based induction,(1)The behavioral results replicated the premise monotonicity effect: S arguments had less “definite” responses(possibly weak or possibly strong)and lower “correct” response rates than those of T arguments;(2)S arguments produced longer reaction times and more conservative response criteria than did T arguments.This suggests that the premise monotonicity effect was affected by both evidence accumulation speed and decision threshold based on the exemplar-based linear ballistic accumulator model of induction;(3)S arguments elicited larger FN400 amplitudes than did T arguments,which was linked to reduced global similarity,decreased cognitive relevance,and attenuated conceptual fluency,and(4)S arguments elicited larger SN amplitudes than did T arguments,which is related to more inference-driven integration and interpretive processes.Our findings provide insight into the complex temporal course of the premise monotonicity effect during semantic category-based induction.