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Having a choice is a basic demand to influence human behavior. However, how various choice levels modulate outcome processing when the outcome is independent of the choices remains unclear. In this event-related potential (ERP) study, thirty-seven participants were instructed to perform a one-person choice task in which they were required to choose one card from 1 (no-choice level), 2 (medium-choice level), and 8 cards (high-choice level) to win a reward, with a 50% chance. Behavioral results indicated that pleasure and perceived control rating scores were linearly promoted with increased choice levels. ERP results revealed that having choices (medium- and high-choice level) elicited greater original-RewP and PCA-RewP amplitudes than having no choice (no-choice level), suggesting the amplification of the reward prediction error by quickly detecting whether there is a choice or not. Moreover, ERP results revealed that the original-P300 amplitudes were linearly enhanced with increased choice levels, suggesting the increased attentional allocation based on the motivational and emotional significance, due to advanced processing of the value of choice levels. Therefore, these results suggest that choice levels can modulate outcome processing, even when the outcome is independent of the choices, and provide further evidence to support the intrinsic value of having choices.

Categorization involves forming equivalence classes of discriminable entities, whereas category-based induction (CBI) involves employing categorical knowledge to generalize novel properties. Previous studies have suggested either common or distinctive cognitive processing between categorization and CBI. However, no study has compared cognitive processes with the same stimuli sets using event-related potentials (ERPs), which help to determine the cognitive processes with a high temporal solution. In this study, we compared the ERP responses to categorization and CBI using two separate experiments (i.e., generic and specific conclusions), with the same task materials. Results from both experiments identified distinctive cognitive processing between categorization and CBI based on a greater proportion of “definitely” responses and smaller amplitudes of sustained negativity during categorization. These observations suggest that categorization involves decreased conflict monitoring and control than CBI under single-premise conditions. Contrastingly, categorization and CBI elicited similar FN400 amplitudes in both experiments, which suggests a common cognitive process between them. These findings present the common and distinctive cognitive processes between categorization and CBI.

The premise monotonicity 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. The timing of brain activity during this effect is unclear. Therefore, the event-related potentials (ERPs) underpinning this 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). The behavioral results replicated the premise monotonicity effect, and revealed that 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. 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 under congruent induction, which was linked to reduced global similarity, decreased cognitive relevance, and attenuated conceptual fluency and (2) S arguments elicited larger sustained negativity (SN) in the 450–1050-ms time window 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.

The present study aimed to provide electrophysiological evidence about acquiring complex numerical rules when unexpected numbers were presented. Hence, we compared the neural correlates underlying the acquisition of unexpected complex rules (e.g., 12, 14, 18, 24) compared to expected simple rules (e.g., 12, 14, 16, 18). The event-related potential (ERP) results for the rule acquisition process for the third numbers showed that, in contrast to expected simple rules, unexpected complex rules elicited: an enhanced N200, reflecting the detection of a conflict between the expected numbers and the displayed numbers; a decreased P300, indicating a feeling of uncertainty accompanied by identifying numerical regularity; and an increased LPC, reflecting the working-memory updating caused by expectancy violation and rule acquisition. These results describe the precise time course of acquiring novel and complex rules when unexpected numbers were presented.

Previous event-related potential (ERP) studies investigating the typicality effects during category-based reasoning were conducted during the deduction and induction phases by comparing typical and atypical conclusion categories, without property inference processes. In the present study, the ERP responses to both conclusion typicality effects (strengthening of the inference from “durian has the novel property X1” to “apple has the novel property X1” [a typical conclusion]was stronger than the inference from “durian has the novel property X1” to “Chinese date has the novel property X1 [an atypical conclusion], experiment 1) and premise typicality effects (strengthening of the inference from “apple has the novel property X1”[a typical premise]to “durian has the novel property X1” was stronger than the inference from “Chinese date has the novel property X1”[an atypical premise] to “durian has the novel property X1”, experiment 2) during category-based induction were measured by separately presenting the conclusion categories and conclusion properties. The results of both the experiments showed that, during the conclusion-category stage, typical conditions elicited larger P2 responses than atypical conditions, suggesting increased semantic feature activity in typical conditions. Additionally, atypical conditions elicited larger N400 responses than typical conditions, suggesting the increased cognitive effort related to semantic integration in atypical conditions than in typical conditions. During the conclusion-property stage, when participants accepted the inferences, both the experiments showed that typical conditions elicited larger P3b responses than atypical conditions, reflecting the higher degree of expected satisfaction during reasoning. Therefore, when the inferences were positive during category-based induction, N400 responses indexed the typicality effects during the conclusion-category stage, whereas P3b responses indexed the typicality effects during the conclusion-property stage.

A premise monotonicity effect during category-based induction is a robust effect, in which participants are more likely to generalize properties shared by many instances rather than those shared by few instances. Previous studies have shown the event-related potentials (ERPs) elicited by this effect. However, the neural oscillations in the brain underlying this effect are not well known, and such oscillations can convey task-related cognitive processing information which is lost in traditional ERP analysis. In the present study, the phase-locked and non-phase-locked power of neural oscillations related to this effect were measured by manipulating the premise sample size [single (S) vs. two (T)] in a semantic category-based induction task. For phase-locked power, the results illustrated that the premise monotonicity effect was revealed by anterior delta power, suggesting differences in working memory updating. The results also illustrated that T arguments evoked larger posterior theta-alpha power than S arguments, suggesting that T arguments led to enhanced subjectively perceived inductive confidence than S arguments. For non-phase-locked power, the results illustrated that the premise monotonicity effect was indicated by anterior theta power, suggesting that the differences in sample size were related to a change in the need for cognitive control and the implementation of adaptive cognitive control. Moreover, the results illustrated that the premise monotonicity effect was revealed by alpha-beta power, which suggested the unification of sentence and inference-driven information. Therefore, the neural oscillation profiles of the premise monotonicity effect during semantic category-based induction were elucidated, and supported the connectionist models of category-based induction.

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.

Previous studies have failed to clarify the event-related potentials (ERPs) that occur in response to categorization and property inferences during category-based induction. The present study examined ERP differences among acceptable-induction conclusions, unrelated-category conclusions, and unrelated-property conclusions to dissociate categorization and property-inference processing during category-based induction. The results showed that: (a) conclusions with categories that were unrelated to the premise evoked greater frontal N2 amplitudes, smaller P3b amplitudes, and greater N400 amplitudes, compared to conclusions with categories that were logically related to the premise; and (b) conclusions with unrelated properties evoked larger late positive components (LPCs) during the 700-800ms time interval compared to conclusions with related properties. These results suggest that the N2-P3b-N400 effects reflect categorization violations, while the LPCs are related to property violations during category-based induction, therefore, the ERP responses to category-related and property-related processes are dissociated respectively during category-based induction.

Category-based inferences allow inductions about novel properties based on categorical memberships (e.g., knowing all trout have genes [premise] allows us to infer that all fish have genes [conclusion]). Natural (N) and artificial (A) domains are the most obvious and traditional distinctions in categorization. The distinct event-related potential (ERP) responses for N and A domains have not yet been examined during category-based inferences. In this study, the differences between ERP inference parameters within N and A domains were measured during inductive decision processing, while controlling the premise−conclusion similarity and premise typicality between those two domains. Twenty-two adults were asked to make a decision on whether a conclusion was definitely weak, possibly weak, possibly strong, or definitely strong, based on a premise. The behavioral results showed that semantic inferences within the N domain shared similar inductive strength, similar “correct” response rates, and similar reaction times with that within the A domain. However, the ERP results showed that semantic inferences elicited smaller frontal-distributed N400 (FN400) amplitudes within the N domain than within the A domain, which suggested that knowledge of the ontological domain of a category affects category-based inferences, and underlaid the increased categorical coherence and homogeneity in the N as compared to the A categories. Therefore, we have distinguished the cognitive course of semantic inferences between N and A domains.

Inductive generalization of novel properties to same-category or similar-looking objects was studied in Chinese preschool children. The effects of category labels on generalizations were investigated by comparing basic-level labels, superordinate-level labels, and a control phrase applied to three kinds of stimulus materials: colored photographs (Experiment 1), realistic line drawings (Experiment 2), and cartoon-like line drawings (Experiment 3). No significant labeling effects were found for photos and realistic drawings, but there were significant effects for cartoon-like drawings. Children made mostly (>70%) category-based inferences about photographs whether or not labels were provided (Experiment 1). Children showed a bias toward category-based inferences about realistic drawings (Experiment 2) but did so only when labels were provided. Finally, children made mostly appearance-based generalizations for cartoon-like drawings (Experiment 3). However, labels (basic or superordinate level) reduced appearance-based responses. Labeling effects did not depend on having identical labels; however, identical superordinate labels were more effective than different basic-level labels for the least informative stimuli (i.e., cartoons). Thus, labels sometimes confirm the identity of ambiguous items. This evidence of labeling effects in Mandarin-speaking Chinese children extends previous findings beyond English-speaking children and shows that the effects are not narrowly culture and language specific. © 2011 Elsevier Inc.

The typicality effect describes a phenomenon whereby a typical item is easier to be judged as a member of a category than are atypical items. This effect has been intensively studied in the context of category verification tasks. The present study further investigated the typicality effect using our newly developed category-based deductive reasoning task. Subjects were required to judge whether an incoming stimulus had the properties described in the premise presented before. The stimuli were either typical or atypical members of four target semantic categories or were non-target stimuli. According to the ERP results, three phases were needed to determine whether the object has the property associated with the category in the premise. First, significant amplitude differences were seen between typical and atypical items at N1, which suggested that attention processing was influenced by the expectation in this up-to-down (deductive) process. The premise automatically induced the expectation of the prototype of one concept, i.e. the expectation for the prototype of birds was induced when the premise was "Birds possess the property C". Typical items (e.g., sparrow) were more similar to the prototype; hence, they were easier to be matched with the prototype induced by the premise than were atypical items (e.g., ostrich). Additionally, there was a dissociation between typical and atypical items at P2, which suggested that the participants' early detection of an item's category membership was influenced by the typicality. Thirdly, N400 effect is related to the process of semantic processes and determining whether the object has the property associated with the category in the premise. N400 mean amplitudes during the 300-500 ms epoch were significantly greater for non-target members than for target members, while words of lower typicality (atypical) evoked greater N400 amplitudes during the 350-450 ms epoch than did words of higher typicality (typical).

The temporal course of the human brain dealing with flexible categorization was analyzed by using an event-related potential (ERP) technique in an animal/non-animal categorization task in two parallel experiments. Participants shown animal, person, mixed and non-animal images were asked if they saw ‘animals’ after being instructed to exclude humans in the category of ‘animals’ in Experiment 1, while they were told to define humans as animals in Experiment 2. The ERP data analysis showed that targets elicited larger P150 amplitudes than non-targets, which may reflect early perceptual detection and selection. Images including humans (person and mixed images) elicited larger anterior N2 amplitudes than animal images, regardless of the polysemy of the animal category, which may reflect an extra load on attention and monitoring processes in flexible categorization. Compared to non-targets, targets elicited larger P3 amplitudes, which may be associated with the categorical decision process.