Independence of valence and reward in emotional word processing: electrophysiological evidence

Reward-related regions play a role in natural story comprehension

The reward system was shown to be involved in a wide array of processes. Nevertheless, the exploration of the involvement of the reward system during language processing has not yet been directly tested. We investigated the role of reward-processing regions while listening to a natural story. We utilized a published dataset in which half of the participants listened to a natural story and the others listened to a scrambled version of it to compare the functional MRI signals in the reward system between these conditions and discovered a distinct pattern between conditions. This suggests that the reward system is activated during the comprehension of natural stories. We also show evidence that the fMRI signals in reward-related areas might potentially correlate with the predictability level of processed sentences. Further research is needed to determine the nature of the involvement and the way the activity interacts with various aspects of the sentences.

Effects of peer victimization on cortical processing of social-evaluative stress in patients with major depressive disorder

Peer victimization contributes to the development of major depressive disorders (MDDs). While previous studies reported differentiated peripheral physiological responses in peer-victimized individuals with depression, little is known about potential alterations of cortical event-related potentials (ERPs) in response to social stimuli in depressive patients with a history of peer victimization. Using a social condition paradigm, the present study examined whether peer victimization alters conditioned cortical responses to potentially threatening social stimuli in MDD patients and healthy controls. In the task, we studied ERPs to conditioned stimuli (CSs), i.e. still images of faces, that were coupled to unconditioned socially negative and neutral evaluative video statements. Peer victimization was related to more pronounced P100 amplitudes in reaction to negative and neutral CSs. Attenuated P200 amplitudes in peer-victimized individuals were found in response to negative CSs. Cortical responses to CSs were not influenced by a diagnosis of MDD. The results suggest altered responsiveness to interpersonal information in peer-victimized individuals. Facilitated early processing of social threat indicators may prevent peer-victimized individuals from adaptive responses to social cues, increasing their vulnerability for depression.

The effect of reward expectation on working memory of emotional faces under different levels of cognitive load: an ERP study

Using event-related potentials (ERPs), this study examined the impact of reward expectations on working memory of emotional faces under different levels of cognitive load in a task combining the N-back paradigm and the reward expectation paradigm. The experiment involved presenting high- or low-reward cues followed by an N-back task for emotional faces with different loads. The accuracy results showed that under a high task load, both reward and emotion effects were significantly observed. However, these effects disappeared under a low task load. Analysis of the ERP data revealed that the early P2 and VPP components exhibited greater responses to fearful faces than to neutral faces. In the later stages, the P3 and LPP components showed greater reactions to high rewards than to low rewards. Additionally, the P2 component was found to be modulated by task load in relation to rewards, the EPN component demonstrated task load modulation with respect to emotions, and the N170 component showed an interaction effect between rewards and emotions. These findings imply that load regulates the reward effect and the emotional superiority effect in the process of working memory for emotional faces. In the cognitive processing of working memory, motivation and emotion jointly influence processing. Emotional factors have a greater impact in the early stage of processing, while motivation factors have a greater impact in the late stage of processing.

Of ugly gains and happy losses: An event-related potential study of interactions of the intrinsic and acquired valence of emotional pictures

During the last decades, event-related potential research on the processing of intrinsic and acquired valence has made great progress, but the two dimensions rarely varied simultaneously. Only that way, however, can we investigate whether the acquisition of extrinsic valence varies with intrinsic valence and whether intrinsic and acquired valence share the same brain mechanisms. Forty-five participants performed associative learning of gains and losses, using pictures varying on intrinsic valence (positive, negative) and outcome (90 % gain, 50 %/50 %, 90 % loss). 64-channel EEG was recorded. During acquisition, one picture from each valence/outcome combination was repeatedly presented, followed by abstract outcome information (+10 ct, -10 ct) at the predefined probability. In the test phase, participants pressed buttons to earn the real gains and avoid the real losses associated with the pictures. Here, effects of outcome and/or its congruence with intrinsic valence were observed for RT, error rate, frontal theta power, posterior P2, P300, and LPP. Moreover, outcome systematically affected post-test valence and arousal ratings. During acquisition, a contingency effect (90 % > 50 %) on amplitude of a frontal negative slow wave accompanied the progress of learning, independently of outcome, valence, and congruence. The relative absence of outcome effects during acquisition suggests "cold" semantic rather than genuinely affective processing of gains and losses. However, with real gains and losses in the test phase, "hot" affective processing took place, and outcome and its congruence with intrinsic valence influenced behavior and neural processing. Finally, the data suggest both shared and distinct brain mechanisms of intrinsic and acquired valence.

Reward History Modulates the Processing of Task-Irrelevant Emotional Faces in a Demanding Task

The aim of the current study was to examine how reward-associated emotional facial distractors could capture attentional resources in a demanding visual task using event-related potentials (ERPs). In the learning phase, a high- or low-reward probability was paired with angry, happy, or neutral faces. Then, in the test phase, participants performed a face-irrelevant task with no reward at stake, in which they needed to discriminate the length of two lines presented in the center of the screen while faces that were taken from the learning phase were used as distractors presented in the periphery. The behavioral results revealed no effect of distractor emotional valence since the emotional information was task-irrelevant. The ERP results in the test phase revealed a significant main effect of distractor emotional valence for the parieto-occipital P200 (170-230 ms); the mean amplitudes in both the angry- and happy-face conditions were more positive than the neutral-face condition. Moreover, we found that the high-reward association enhanced both the N170 (140-180 ms) and EPN (260-330 ms) relative to the low-reward association condition. Finally, the N2pc (270-320 ms) also exhibited enhanced neural activity in the high-reward condition compared to the low-reward condition. The absence of emotional effects indicated that task-irrelevant emotional facial stimuli did not impact behavioral or neural responses in this highly demanding task. However, reward-associated information was processed when attention was directed elsewhere, suggesting that the processing of reward-associated information worked more in an automatic way, irrespective of the top-down task demand.

Regulatory Effects of Reward Anticipation and Target on Attention Processing of Emotional Stimulation

Studies suggest that reward and emotion are interdependent. However, there are discrepancies regarding the interaction between these variables. Some researchers speculate that the inconsistent findings may be due to different targets being used. Although reward and emotion both affect attention, it is not clear whether their impacts are independent. This study examined the impact of reward anticipation on emotion processing for different targets. A cue-target paradigm was used, and behavior and eye-tracking data were recorded in an emotion or sex recognition task under the conditions of reward and non-reward anticipation. The results showed that when the target was related to the emotional attribute of the stimulus, the reward promoted the processing target information, thereby generating reward-oriented attention. When the target was unrelated to the emotional attributes of the stimulus, the reward did not promote the processing target information, and at the same time, individuals had negative emotional biases toward the emotional faces. The results revealed that, in addition to affecting the attention to emotional faces independently, the target regulated the promotion of reward anticipation to emotional attention and attention bias toward negative stimuli.

Working memory load affects early affective responses to concrete and abstract words differently: Evidence from ERPs

Early posterior negativity (EPN) is an early-occurring, event-related, potential that is elicited by pictures and words that have highly arousing characteristics. Whilst EPN has been found with words presented in isolation several times, different types of words have shown quite different effects across different types of tasks. One possible reason for this is that memory and attentional demands may affect the way semantic features of words are processed, and this may modulate EPN. This was investigated in a silent reading task using abstract and concrete words of negative and neutral valence and a dual phonological working memory task to manipulate memory load. The results showed that abstract but not concrete words elicited EPN, and this may have affected downstream processing. Further analyses examining alpha desynchronization showed that negative concrete words appeared to be significantly affected by the memory load manipulation, unlike negative abstract words. These results provide evidence that the processing of features in negative concrete words is more affected by working memory and attentional demands than the processing of features in negative abstract words, and this may be responsible for the failure of negative concrete words to elicit EPN in this study. Thus, the extent to which words elicit EPN appears to be dependent on both their semantic representations and competing cognitive processes. These results provide a potential explanation for some of the differences that have been reported in previous experiments as well as insight into how memory and attention can affect the processing of the semantic features of words.

Neural Dynamic Responses of Monetary and Social Reward Processes in Adolescents

Adolescence is an essential developmental period characterized by reward-related processes. The current study investigated the development of monetary and social reward processes in adolescents compared with that in children and adults; furthermore, it assessed whether adolescents had different levels of sensitivity to various types of rewards. Two adapted incentive delay tasks were employed for each participant, and event-related potentials (ERPs) were recorded. The behavioral results showed that both monetary and social rewards could motivate response speed, and participants were more accurate under the monetary reward condition than under the social reward condition. The behavioral performances of individuals increased with age. For the ERP data, the cue-P3, target-P2, target-P3 and feedback-related negativity (FRN) components were investigated to identify reward motivation, emotional arousal, attention allocation and feedback processing. Children and adolescents showed higher motivation (larger cue-P3) to rewards than adults. Adolescents showed larger emotional responses to rewards; that is, they had larger target-P2 amplitudes than adults and shorter target-P2 latencies than children. Children showed stronger emotional reactivity for monetary rewards than for social rewards. All age groups had stronger attentional control (larger target-P3) under the monetary reward condition than under the social reward condition. The present study sheds light on the neurodevelopment of reward processes in children, adolescents and adults and shows that various reward process stages demonstrate different age-related and reward-type-related characteristics.

Emotional Interference in Early Adolescence: Positive Reinforcement Modulates the Behavioral and Neural Effects of Negative Emotional Distracters

Limited research has examined functioning within fronto-limbic systems subserving the resistance to emotional interference in adolescence despite evidence indicating that alterations in these systems are implicated in the developmental trajectories of affective disorders. This study examined the functioning of fronto-limbic systems subserving emotional interference in early adolescence and whether positive reinforcement could modulate these systems to promote resistance to emotional distraction. Fifty healthy early adolescents (10-13 years old) completed an emotional delayed working memory (WM) paradigm in which no distractors (fixation crosshair) and emotional distracters (neutral and negative images) were presented with and without positive reinforcement for correct responses. WM accuracy decreased with negative distracters relative to neutral distracters and no distracters, and activation increased in amygdala and prefrontal cortical (PFC) regions (ventrolateral, dorsomedial, ventromedial, and subgenual anterior cingulate) with negative distracters compared with those with no distracters. Reinforcement improved performance and reduced activation in the amygdala, dorsomedial PFC, and ventrolateral PFC. Decreases in amygdala activation to negative distracters due to reinforcement mediated observed decreases in reaction times. These findings demonstrate that healthy adolescents recruit similar fronto-limbic systems subserving emotional interference as adults and that positive reinforcement can modulate fronto-limbic systems to promote resistance to emotional distraction.

Emotional Contexts Modulate Anticipatory Late Positive Component and Reward Feedback Negativity in Adolescents With Major Depressive Disorder

BACKGROUND

Neuroimaging research has determined deficits in the dopaminergic circuit of major depressive disorder (MDD) during adolescence. This study investigated how emotional contexts modulate the temporal dynamics of reward anticipation and feedback in adolescents.

METHODS

EEG data from 35 MDD and 37 healthy adolescents were recorded when they conducted a gambling task after being presented with emotional pictures.

RESULTS

The results demonstrated that both MDD and healthy adolescents exhibited the largest late positive component (LPC) in positive contexts at the frontal sites and the largest LPC in negative contexts at the central sites; however, MDD adolescents exhibited anticipatory LPC hypoactivation than healthy adolescents. However, MDD adolescents exhibited smaller gain feedback negativity (FN) than healthy adolescents independent of emotional contexts, positively correlating with the trait anhedonia according to the consummatory aspect of the Temporal Experience of Pleasure Scale. In contrast, MDD adolescents exhibited greater FN loss in positive and neutral contexts than healthy adolescents while no difference in FN loss was found between the two groups in negative contexts. Moreover, the FN loss amplitudes negatively correlated with hedonic tone according to the Snaith-Hamilton Pleasure Scale over the past week.

CONCLUSIONS

These findings suggest that MDD adolescents exhibited dissociable deficits in reward anticipation and gain or loss feedback that are distinctly modulated by emotional contexts, and they deepen our understanding of the modulation of emotional contexts on the temporal dynamic reorganization of the reward circuit in MDD adolescents.

Differential Impact of Emotion on Semantic Processing of Abstract and Concrete Words: ERP and fMRI Evidence

Emotional valence is known to influence word processing dependent upon concreteness. Whereas some studies point towards stronger effects of emotion on concrete words, others claim amplified emotion effects for abstract words. We investigated the interaction of emotion and concreteness by means of fMRI and EEG in a delayed lexical decision task. Behavioral data revealed a facilitating effect of high positive and negative valence on the correct processing of abstract, but not concrete words. EEG data yielded a particularly low amplitude response of the late positive component (LPC) following concrete neutral words. This presumably indicates enhanced allocation of processing resources to abstract and emotional words at late stages of word comprehension. In fMRI, interactions between concreteness and emotion were observed within the semantic processing network: the left inferior frontal gyrus (IFG) and the left middle temporal gyrus (MTG). Higher positive or negative valence appears to facilitate semantic retrieval and selection of abstract words. Surprisingly, a reversal of this effect occurred for concrete words. This points towards enhanced semantic control for emotional concrete words compared to neutral concrete words. Our findings suggest fine-tuned integration of emotional valence and concreteness. Specifically, at late processing stages, semantic control mechanisms seem to integrate emotional cues depending on the previous progress of semantic retrieval.

Effects of valence and arousal on affective priming vary with the degree of affective experience denoted by words

We investigated whether the effect of the valence and arousal of less or more affective experiential words on affective priming using event-related potentials (ERPs). The stimuli included less affective experiential (LE) words (Experiment 1) and more affective experiential (ME) words (Experiment 2) that were organized in an orthogonal design, with valence (positive and negative) and arousal (low and high) as factors in a lexical decision task. In Experiment 1, the results revealed no obvious effect of affective priming on response times (RTs) or ERPs for LE words. In Experiment 2, affective priming effects of ME words were influenced interactively by valence and arousal. Specifically, for positive ME words with high- and low-arousal, affectively incongruent trials were associated with longer RTs and enhanced late positive components (LPCs, 430-700 ms) compared with congruent trials (a positive effect). For negative ME words with low-arousal, no significant differences in RTs or LPC amplitudes were found between affectively congruent and incongruent trials (a null effect), whereas for negative ME words with high-arousal, the processing of congruent trials was associated with longer RTs and enhanced LPC amplitudes over that of incongruent trials (a reversal effect). On the one hand, our findings suggest that LE and ME words as primes produce different effects on the processing of subsequently presented targets. On the other hand, our findings further indicate that there seems to have a continuous transition from the spreading activation of ME words to an inhibition process in semantic memory along with their valence and arousal, which is involved in decision-making processes and memory-related stages.

Increased neural sensitivity to self-relevant stimuli in major depressive disorder

The current research examined how individuals with depression process emotional, self-relevant stimuli. Across two studies, individuals with depression and healthy controls read stimuli that varied in self-relevance while EEG data were recorded. We examined the late positive potential (LPP), an ERP component that captures the dynamic allocation of attention to motivationally salient stimuli. In Study 1, participants read single words in a passive-viewing task. Participants viewed negative, positive, or neutral words that were either normative or self-generated. Exploratory analyses indicated that participants with depression exhibited affective modulation of the LPP for self-generated stimuli only (both positive and negative) and not for normative stimuli; healthy controls exhibited similar affective modulation of the LPP for both self-relevant and normative stimuli. In Study 2, using a separate sample and a different task, stimuli were provided within the context of sentence stems referring to the self or other people. Participants with depression were more likely to endorse negative self-referent sentences and reject positive ones compared to healthy controls. Depressed participants also exhibited an increased LPP to negative stimuli compared to positive or neutral stimuli. Together, these two studies suggest that depression is characterized by relatively increased sensitivity to affective self-relevant stimuli, perhaps in the context of a broader reduction in emotional reactivity to stimuli that are not self-relevant. Thus, depression may be characterized by a more nuanced pattern based on the degree of stimulus self-relevance than either a global decrease or increase in reactivity to affective stimuli.

Money or smiles: Independent ERP effects of associated monetary reward and happy faces

In comparison to neutral faces, facial expressions of emotion are known to gain attentional prioritization, mainly demonstrated by means of event-related potentials (ERPs). Recent evidence indicated that such a preferential processing can also be elicited by neutral faces when associated with increased motivational salience via reward. It remains, however, an open question whether impacts of inherent emotional salience and associated motivational salience might be integrated. To this aim, expressions and monetary outcomes were orthogonally combined. Participants (N = 42) learned to explicitly categorize happy and neutral faces as either reward- or zero-outcome-related via an associative learning paradigm. ERP components (P1, N170, EPN, and LPC) were measured throughout the experiment, and separately analyzed before (learning phase) and after (consolidation phase) reaching a pre-defined learning criterion. Happy facial expressions boosted early processing stages, as reflected in enhanced amplitudes of the N170 and EPN, both during learning and consolidation. In contrast, effects of monetary reward became evident only after successful learning and in form of enlarged amplitudes of the LPC, a component linked to higher-order evaluations. Interactions between expressions and associated outcome were absent in all ERP components of interest. The present study provides novel evidence that acquired salience impacts stimulus processing but independent of the effects driven by happy facial expressions.

Potential reward reduces the adverse impact of negative distractor stimuli

Knowledge about interactions between reward and negative processing is rudimentary. Here, we employed functional MRI to probe how potential reward signaled by advance cues alters aversive distractor processing during perception. Behaviorally, the influence of aversive stimuli on task performance was reduced during the reward compared to no-reward condition. In the brain, at the task phase, paralleling the observed behavioral pattern, we observed significant interactions in the anterior insula and dorsal anterior cingulate cortex, such that responses during the negative (vs neutral) condition were reduced during the reward compared to no-reward condition. Notably, negative distractor processing in the amygdala appeared to be independent of the reward manipulation. During the initial cue phase, we observed increased reward-related responses in the ventral striatum/accumbens, which were correlated with behavioral interference scores at the subsequent task phase, revealing that participants with increased reward-related responses exhibited a greater behavioral benefit of reward in reducing the adverse effect of negative images. Furthermore, during processing of reward (vs no-reward) cues, the ventral striatum exhibited stronger functional connectivity with fronto-parietal regions important for attentional control. Together, our findings contribute to the understanding of how potential reward influences attentional control and reduces negative distractor processing in the human brain.

Are Emotions Abstract or Concrete?

The ability to identify and communicate emotions is essential to psychological well-being. Yet research focusing exclusively on emotion concepts has been limited. This study examined nouns that represent emotions (e.g., pleasure, guilt) in comparison to nouns that represent abstract (e.g., wisdom, failure) and concrete entities (e.g., flower, coffin). Twenty-five healthy participants completed a lexical decision task. Event-related potential (ERP) data showed that emotion nouns elicited less pronounced N400 than both abstract and concrete nouns. Further, N400 amplitude differences between emotion and concrete nouns were evident in both hemispheres, whereas the differences between emotion and abstract nouns had a left-lateralized distribution. These findings suggest representational distinctions, possibly in both verbal and imagery systems, between emotion concepts versus other concepts, implications of which for theories of affect representations and for research on affect disorders merit further investigation.

Spanish norms for affective and lexico-semantic variables for 1,400 words

Studies of semantic variables (e.g., concreteness) and affective variables (i.e., valence and arousal) have traditionally tended to run in different directions. However, in recent years there has been growing interest in studying the relationship, as well as the potential overlaps, between the two. This article describes a database that provides subjective ratings for 1,400 Spanish words for valence, arousal, concreteness, imageability, context availability, and familiarity. Data were collected online through a process involving 826 university students. The results showed a high interrater reliability for all of the variables examined, as well as high correlations between our affective and semantic values and norms currently available in other Spanish databases. Regarding the affective variables, the typical quadratic correlation between valence and arousal ratings was obtained. Likewise, significant correlations were found between the lexico-semantic variables. Importantly, we obtained moderate negative correlations between emotionality and both concreteness and imageability. This is in line with the claim that abstract words have more affective associations than concrete ones (Kousta, Vigliocco, Vinson, Andrews, & Del Campo, 2011). The present Spanish database is suitable for experimental research into the effects of both affective properties and lexico-semantic variables on word processing and memory.

Shock and awe: Distinct effects of taboo words on lexical decision and free recall

Taboo stimuli are highly arousing, but it has been suggested that they also have inherent taboo-specific properties such as tabooness, offensiveness, or shock value. Prior studies have shown that taboo words have slower response times in lexical decision and higher recall probabilities in free recall; however, taboo words often differ from other words on more than just arousal and taboo properties. Here, we replicated both of these findings and conducted detailed item analyses to determine which word properties drive these behavioural effects. We found that lexical-decision performance was best explained by measures of lexical accessibility (e.g., word frequency) and tabooness, rather than arousal, valence, or offensiveness. However, free-recall performance was primarily driven by emotional word properties, and tabooness was the most important emotional word property for model fit. Our results suggest that the processing of taboo words is influenced by distinct sets of factors and by an intrinsic taboo-specific property.

Affective Norms for 4900 Polish Words Reload (ANPW_R): Assessments for Valence, Arousal, Dominance, Origin, Significance, Concreteness, Imageability and, Age of Acquisition

In studies that combine understanding of emotions and language, there is growing demand for good-quality experimental materials. To meet this expectation, a large number of 4905 Polish words was assessed by 400 participants in order to provide a well-established research method for everyone interested in emotional word processing. The Affective Norms for Polish Words Reloaded (ANPW_R) is designed as an extension to the previously introduced the ANPW dataset and provides assessments for eight different affective and psycholinguistic measures of Valence, Arousal, Dominance, Origin, Significance, Concreteness, Imageability, and subjective Age of Acquisition. The ANPW_R is now the largest available dataset of affective words for Polish, including affective scores that have not been measured in any other dataset (concreteness and age of acquisition scales). Additionally, the ANPW_R allows for testing hypotheses concerning dual-mind models of emotion and activation (origin and subjective significance scales). Participants in the current study assessed all 4905 words in the list within 1 week, at their own pace in home sessions, using eight different Self-assessment Manikin (SAM) scales. Each measured dimension was evaluated by 25 women and 25 men. The ANPW_R norms appeared to be reliable in split-half estimation and congruent with previous normative studies in Polish. The quadratic relation between valence and arousal was found to be in line with previous findings. In addition, nine other relations appeared to be better described by quadratic instead of linear function. The ANPW_R provides well-established research materials for use in psycholinguistic and affective studies in Polish-speaking samples.

Effects of valence and arousal on emotional word processing are modulated by concreteness: Behavioral and ERP evidence from a lexical decision task

We investigated whether the effects of valence and arousal on emotional word processing are modulated by concreteness using event-related potentials (ERPs). The stimuli included concrete words (Experiment 1) and abstract words (Experiment 2) that were organized in an orthogonal design, with valence (positive and negative) and arousal (low and high) as factors in a lexical decision task. In Experiment 1, the impact of emotion on the effects of concrete words mainly resulted from the contribution of valence. Positive concrete words were processed more quickly than negative words and elicited a reduction of N400 (300-410ms) and enhancement of late positive complex (LPC; 450-750ms), whereas no differences in response times or ERPs were found between high and low levels of arousal. In Experiment 2, the interaction between valence and arousal influenced the impact of emotion on the effects of abstract words. Low-arousal positive words were associated with shorter response times and a reduction of LPC amplitudes compared with high-arousal positive words. Low-arousal negative words were processed more slowly and elicited a reduction of N170 (140-200ms) compared with high-arousal negative words. The present study indicates that word concreteness modulates the contributions of valence and arousal to the effects of emotion, and this modulation occurs during the early perceptual processing stage (N170) and late elaborate processing stage (LPC) for emotional words and at the end of all cognitive processes (i.e., reflected by response times). These findings support an embodied theory of semantic representation and help clarify prior inconsistent findings regarding the ways in which valance and arousal influence different stages of word processing, at least in a lexical decision task.

Development and Validation of a Persian Version of Dichotic Emotional Word Test

INTRODUCTION

Emotional words in comparison with neutral words have different hemispheric specialization. It is assumed that the right hemisphere has a role in processing every kind of emotional word. The objective of the present study was the development of a Persian version of the dichotic emotional word test and evaluate its validation among adult Persian speakers.

MATERIALS AND METHODS

The present study was done on 60 adults, with the age ranging from 18-30 years for both genders, who had no history of neurological disorders with normal hearing. The developed test included eight main lists; each had several dichotic emotional/ neutral pairs of words. Participants were asked to recall as many words in each list as they could after they listened to them. A content validity index was used to analyze the validity of the test.

RESULTS

The mean content validity index score was 0.94. The findings showed that in the left ear, emotional words were remembered more than neutral ones (P=0.007). While in the right ear, neutral words were remembered more (P=0.009). There were no significant differences in male and female scores.

CONCLUSION

Dichotic emotional word test has a high content validity. The ability to remember emotional words better in the left ear supports the dominant role of the right hemisphere in emotional word perception.

Reward expectation regulates brain responses to task-relevant and task-irrelevant emotional words: ERP evidence

We investigated the effect of reward expectation on the processing of emotional words in two experiments using event-related potentials (ERPs). A cue indicating the reward condition of each trial (incentive vs non-incentive) was followed by the presentation of a negative or neutral word, the target. Participants were asked to discriminate the emotional content of the target word in Experiment 1 and to discriminate the color of the target word in Experiment 2, rendering the emotionality of the target word task-relevant in Experiment 1, but task-irrelevant in Experiment 2. The negative bias effect, in terms of the amplitude difference between ERPs for negative and neutral targets, was modulated by the task-set. In Experiment 1, P31 and early posterior negativity revealed a larger negative bias effect in the incentive condition than that in the non-incentive condition. However, in Experiment 2, P31 revealed a diminished negative bias effect in the incentive condition compared with that in the non-incentive condition. These results indicate that reward expectation improves top-down attentional concentration to task-relevant information, with enhanced sensitivity to the emotional content of target words when emotionality is task-relevant, but with reduced differential brain responses to emotional words when their content is task-irrelevant.

Origin of Emotion Effects on ERP Correlates of Emotional Word Processing: The Emotion Duality Approach

We distinguish two evaluative systems which evoke automatic and reflective emotions. Automatic emotions are direct reactions to stimuli whereas reflective emotions are always based on verbalized (and often abstract) criteria of evaluation. We conducted an electroencephalography (EEG) study in which 25 women were required to read and respond to emotional words which engaged either the automatic or reflective system. Stimulus words were emotional (positive or negative) and neutral. We found an effect of valence on an early response with dipolar fronto-occipital topography; positive words evoked a higher amplitude response than negative words. We also found that topographically specific differences in the amplitude of the late positive complex were related to the system involved in processing. Emotional stimuli engaging the automatic system were associated with significantly higher amplitudes in the left-parietal region; the response to neutral words was similar regardless of the system engaged. A different pattern of effects was observed in the central region, neutral stimuli engaging the reflective system evoked a higher amplitudes response whereas there was no system effect for emotional stimuli. These differences could not be reduced to effects of differences between the arousing properties and concreteness of the words used as stimuli.

The effects of gender and self-insight on early semantic processing

This event-related potential (ERP) study explored individual differences associated with gender and level of self-insight in early semantic processing. Forty-eight Chinese native speakers completed a semantic judgment task with three different categories of words: abstract neutral words (e.g., logic, effect), concrete neutral words (e.g., teapot, table), and emotion words (e.g., despair, guilt). They then assessed their levels of self-insight. Results showed that women engaged in greater processing than did men. Gender differences also manifested in the relationship between level of self-insight and word processing. For women, level of self-insight was associated with level of semantic activation for emotion words and abstract neutral words, but not for concrete neutral words. For men, level of self-insight was related to processing speed, particularly in response to abstract and concrete neutral words. These findings provide electrophysiological evidence for the effects of gender and self-insight on semantic processing and highlight the need to take into consideration subject variables in related research.