Size does matter! Perceptual stimulus properties affect event-related potentials during feedback processing

The impact of social comparison on self-deception: An event-related potentials study

Self-deception refers to an individual holding inflated beliefs about their abilities, and it plays a crucial role in human behavior and decision-making. The present study employed event-related potentials (ERPs) technique to explore the neural responses to the impacts of social comparison direction and comparison gap on self-deceptive behavior. They were instructed to predict their performance in the forward-looking paradigm. Behavioral responses and neural reactions during the decision-making process were documented. The behavioral results indicated that, in contrast to the downward comparison condition, participants engaged in upward comparison exhibited more occurrences of self-deception. However, within the context of upward comparison, participants demonstrated a higher frequency of self-deception in the large gap condition compared with the small gap condition. The ERP results showed that induced self-deception under conditions with a large comparative gap between participants and their paired counterparts stimulated larger P300 and smaller N400 amplitude than under conditions with a small gap. However, when participants were in the upward comparison situation, the late positive potential (LPP) amplitude induced by self-deception behavior in the condition of a large comparison gap between participants and paired opponents was larger than that in the condition of a small comparison gap. These results indicated that individuals in the large gap group feel strong unfairness and negative emotions. More importantly, the self-deception induced by the large gap group in the upward comparison situation used fewer cognitive resources than the small gap condition, whereas the individuals in the downward comparison situation did not show the difference in cognitive resources.

Electrophysiological correlates of face and object perception: A comparative analysis of 2D laboratory and virtual reality conditions

Human face perception is a specialized visual process with inherent social significance. The neural mechanisms reflecting this intricate cognitive process have evolved in spatially complex and emotionally rich environments. Previous research using VR to transfer an established face perception paradigm to realistic conditions has shown that the functional properties of face-sensitive neural correlates typically observed in the laboratory are attenuated outside the original modality. The present study builds on these results by comparing the perception of persons and objects under conventional laboratory (PC) and realistic conditions in VR. Adhering to established paradigms, the PC- and VR modalities both featured images of persons and cars alongside standard control images. To investigate the individual stages of realistic face processing, response times, the typical face-sensitive N170 component, and relevant subsequent components (L1, L2; pre-, post-response) were analyzed within and between modalities. The between-modality comparison of response times and component latencies revealed generally faster processing under realistic conditions. However, the obtained N170 latency and amplitude differences showed reduced discriminative capacity under realistic conditions during this early stage. These findings suggest that the effects commonly observed in the lab are specific to monitor-based presentations. Analyses of later and response-locked components showed specific neural mechanisms for identification and evaluation are employed when perceiving the stimuli under realistic conditions, reflected in discernible amplitude differences in response to faces and objects beyond the basic perceptual features. Conversely, the results do not provide evidence for comparable stimulus-specific perceptual processing pathways when viewing pictures of the stimuli under conventional laboratory conditions.

Additive effects of emotional expression and stimulus size on the perception of genuine and artificial facial expressions: an ERP study

Seeing an angry individual in close physical proximity can not only result in a larger retinal representation of that individual and an enhanced resolution of emotional cues, but may also increase motivation for rapid visual processing and action preparation. The present study investigated the effects of stimulus size and emotional expression on the perception of happy, angry, non-expressive, and scrambled faces. We analyzed event-related potentials (ERPs) and behavioral responses of N = 40 participants who performed a naturalness classification task on real and artificially created facial expressions. While the emotion-related effects on accuracy for recognizing authentic expressions were modulated by stimulus size, ERPs showed only additive effects of stimulus size and emotional expression, with no significant interaction with size. This contrasts with previous research on emotional scenes and words. Effects of size were present in all included ERPs, whereas emotional expressions affected the N170, EPN, and LPC, irrespective of size. These results imply that the decoding of emotional valence in faces can occur even for small stimuli. Supra-additive effects in faces may necessitate larger size ranges or dynamic stimuli that increase arousal.

Modulating the difficulty of a visual oddball-like task and P3m amplitude

It is often necessary to modulate the difficulty of an experimental task without changing physical stimulus characteristics that are known to modulate event-related potentials. Here, we developed a new, oddball-like visual discrimination task with varying levels of difficulty despite using almost identical visual stimuli. Gabor patches of one orientation served as frequent standard stimuli with 75% probability. Gabor patches with a slightly different orientation served as infrequent target stimuli (25% probability). Analyzing the behavioral outcomes revealed a successful modulation of task difficulty, i.e. the hard condition revealed decreased d' values and longer reaction times for standard stimuli. In addition, we recorded MEG and computed event-related fields in response to the stimuli. In line with our expectation, the amplitude of the P3m was reduced in the hard condition. We localized the sources of the P3m with a focus on those that are modulated by changes in task difficulty. The sources of P3m modulation by difficulty were found primarily in the centro-parietal regions of both hemispheres. Additionally, we found significant differences in source activity between the easy and hard conditions in parts of the pre and post-central gyrus and inferior parietal lobe. Our findings are in line with previous research suggesting that the brain areas responsible for the conventional P3m generators also contribute to a modulation by task difficulty.

Feedback processing in cognitive and motor tasks: A meta-analysis on the feedback-related negativity

For motor learning, the processing of behavioral outcomes is of high significance. The feedback-related negativity (FRN) is an event-related potential, which is often described as a correlate of the reward prediction error in reinforcement learning. The number of studies examining the FRN in motor tasks is increasing. This meta-analysis summarizes the component in the motor domain and compares it to the cognitive domain. Therefore, a data set of a previous meta-analysis in the cognitive domain that comprised 47 studies  was reanalyzed and compared to additional 25 studies of the motor domain. Further, a moderator analysis for the studies in the motor domain was conducted. The FRN amplitude was higher in the motor domain than in the cognitive domain. This might be related to a higher task complexity and a higher feedback ambiguity of motor tasks. The FRN latency was shorter in the motor domain than in the cognitive domain. Given that sensory information can be used as an external feedback predictor prior to the presentation of the final feedback, reward processing in the motor domain may have been faster and reduced the FRN latency. The moderator variable analysis revealed that the feedback modality influenced the FRN latency, with shorter FRN latencies after bimodal than after visual feedback. Processing of outcome feedback seems to share basic principles in both domains; however, differences exist and should be considered in FRN studies. Future research is motivated to scrutinize the effects of bimodal feedback and other moderators within the motor domain.

Perceptual contrast reduces the judgments of learning of small-font words and increases the judgments of learning of large-font words compared with the no-contrast conditions

The font-size effect on judgments of learning (JOLs) refers to large-font words being rated as more memorable than small ones when required to predict memory performance during the study phase. This study examines perceptual contrast as the prerequisite for this font-size effect on JOLs and explores how perceptual contrast leads to this effect. In Experiment 1, perceptual contrast was achieved by inserting words with one font (e.g., 18 pt) into a series of words with another font (e.g., 70 pt) at a particular proportion (1:4). In Experiment 2, perceptual contrast was manipulated by presenting two different font words up and down in a pair. The results of both experiments showed that: (1) participants rated higher JOLs for large than small fonts under the contrast conditions, but the JOL difference between the two fonts was not significant under the no-contrast conditions; (2) the JOLs of small-font words under the contrast conditions was reduced compared with the no-contrast conditions, but the JOLs of large-font words under the contrast conditions was increased compared with the no-contrast conditions. These results indicated that perceptual contrast was the prerequisite for the font-size effect on JOLs. The reason for this effect is that, compared to no-contrast conditions, perceptual contrast reduces the JOLs of small-font words while increasing the JOLs of large-font words. This study may deepen researchers' understanding of the mechanism of the font-size effect on JOLs and help educators effectively guide students to learn.

Evaluation of Single-Trial Classification to Control a Visual ERP-BCI under a Situation Awareness Scenario

An event-related potential (ERP)-based brain-computer interface (BCI) can be used to monitor a user's cognitive state during a surveillance task in a situational awareness context. The present study explores the use of an ERP-BCI for detecting new planes in an air traffic controller (ATC). Two experiments were conducted to evaluate the impact of different visual factors on target detection. Experiment 1 validated the type of stimulus used and the effect of not knowing its appearance location in an ERP-BCI scenario. Experiment 2 evaluated the effect of the size of the target stimulus appearance area and the stimulus salience in an ATC scenario. The main results demonstrate that the size of the plane appearance area had a negative impact on the detection performance and on the amplitude of the P300 component. Future studies should address this issue to improve the performance of an ATC in stimulus detection using an ERP-BCI.

Real-life relevant face perception is not captured by the N170 but reflected in later potentials: A comparison of 2D and virtual reality stimuli

The perception of faces is one of the most specialized visual processes in the human brain and has been investigated by means of the early event-related potential component N170. However, face perception has mostly been studied in the conventional laboratory, i.e., monitor setups, offering rather distal presentation of faces as planar 2D-images. Increasing spatial proximity through Virtual Reality (VR) allows to present 3D, real-life-sized persons at personal distance to participants, thus creating a feeling of social involvement and adding a self-relevant value to the presented faces. The present study compared the perception of persons under conventional laboratory conditions (PC) with realistic conditions in VR. Paralleling standard designs, pictures of unknown persons and standard control images were presented in a PC- and a VR-modality. To investigate how the mechanisms of face perception differ under realistic conditions from those under conventional laboratory conditions, the typical face-specific N170 and subsequent components were analyzed in both modalities. Consistent with previous laboratory research, the N170 lost discriminatory power when translated to realistic conditions, as it only discriminated faces and controls under laboratory conditions. Most interestingly, analysis of the later component [230–420 ms] revealed more differentiated face-specific processing in VR, as indicated by distinctive, stimulus-specific topographies. Complemented by source analysis, the results on later latencies show that face-specific neural mechanisms are applied only under realistic conditions (A video abstract is available in the Supplementary material and via YouTube: https://youtu.be/TF8wiPUrpSY).

Event-related brain potentials reflect predictive coding of anticipated economic change

Research has demonstrated the importance of economic forecasts for financial decisions at the aggregate economic level. However, little is known about the psychological and neurophysiological mechanisms that economic forecasts activate at the level of individual decision-making. In the present study, we used event-related brain potentials (ERPs) to test the hypothesis that economic forecasts influence individuals’ internal model of the economy and their subsequent decision behavior. Using a simple economic decision-making game, the Balloon Analogue of Risk Task (BART) and predictive messages about possible economic changes in the game before each block, we test the idea that brain potentials time-locked to decision outcomes can vary as a function of exposure to economic forecasts. Behavioural results indicate that economic forecasts influenced the amount of risk that participants were willing to take. Analyses of brain potentials indicated parametric increases of the N1, P2, P3a, and P3b amplitudes as a function of the level of risk in subsequent inflation steps in the BART. Mismatches between economic forecasts and decision outcomes in the BART (i.e., reward prediction errors) were reflected in the amplitude of the P2, P3a, and P3b, suggesting increased attentional processing of unexpected outcomes. These electrophysiological results corroborate the idea that economic messages may indeed influence people’s beliefs about the economy and bias their subsequent financial decision-making. Our findings present a first important step in the development of a low-level neurophysiological model that may help to explain the self-fulfilling prophecy effect of economic news in the larger economy.

Examination of Driver Visual and Cognitive Responses to Billboard Elicited Passive Distraction Using Eye-Fixation Related Potential

Distractions external to a vehicle contribute to visual attention diversion that may cause traffic accidents. As a low-cost and efficient advertising solution, billboards are widely installed on side of the road, especially the motorway. However, the effect of billboards on driver distraction, eye gaze, and cognition has not been fully investigated. This study utilises a customised driving simulator and synchronised electroencephalography (EEG) and eye tracking system to investigate the cognitive processes relating to the processing of driver visual information. A distinction is made between eye gaze fixations relating to stimuli that assist driving and others that may be a source of distraction. The study compares the driver’s cognitive responses to fixations on billboards with fixations on the vehicle dashboard. The measured eye-fixation related potential (EFRP) shows that the P1 components are similar; however, the subsequent N1 and P2 components differ. In addition, an EEG motor response is observed when the driver makes an adjustment of driving speed when prompted by speed limit signs. The experimental results demonstrate that the proposed measurement system is a valid tool in assessing driver cognition and suggests the cognitive level of engagement to the billboard is likely to be a precursor to driver distraction. The experimental results are compared with the human information processing model found in the literature.

Comparing the motivational value of rewards and losses in an EEG-pupillometry study

We found earlier that performance-contingent rewards lead to faster performance than equivalent losses [Carsten, Hoofs, Boehler, & Krebs, 2019. Motivation Science, 5(3). http://dx.doi.org/10.1037/mot0000117]. Here, we further tested the hypothesis that motivation to gain rewards is higher than to avoid losses, even when incentive values are matched. As implicit markers of motivation, we assessed electroencephalography (EEG) focusing on the P3 after target and feedback onset, and the Feedback-Related Negativity (FRN), as well as simultaneously recorded pupil size. Comparing only reward and loss prospect trials in Experiment 1, we found no consistent differences in behavior and electrophysiological markers of motivation, although pupil data suggested higher arousal after feedback in potential-loss trials. Including additional no-incentive trials in Experiment 2, we found consistent evidence that motivation to gain rewards was higher than to avoid losses: In line with behavior, the target-P3 was most pronounced for reward-related stimuli, followed by loss and no-incentive ones. This same ranking was found in the P3 and the FRN after positive outcomes (i.e., reward, avoided loss, and correct feedback in no-incentive trials). Negative outcomes featured a different pattern in line with the pupil response, which suggests that losses are emotionally salient events, without invigorating behavior proportionally. In sum, these findings suggest that the motivation to gain rewards is more pronounced than motivation to avoid equivalent losses, at least in tasks promoting transient increases in attention triggered by incentive prospect. These motivational differences may arise as avoided losses are not profitable in the long term, in contrast to gained rewards.

Converging electrophysiological evidence for a processing advantage of social over nonsocial feedback

We recently demonstrated a processing advantage of social versus nonsocial feedback stimuli in a western sample by assessing phase-locked neural responses. The current study extended our previous findings to another cultural sample (Chinese) to further test whether non-phase-locked neural oscillations also exhibit the social feedback processing advantage. Fifty-three Chinese volunteers performed a time estimation task with social and nonsocial feedback stimuli (matched for complexity) while electroencephalogram was recorded. Almost entirely replicating our previous results, feedback ERPs showed a processing advantage for social compared with nonsocial stimuli. Importantly, non-phase-locked oscillations also revealed this pattern. Frontal midline theta (FMΘ) oscillations differentiated between negative and positive feedback to a larger extent in response to social compared with nonsocial feedback. The current findings imply a rather universal effect of social stimulus characteristics during feedback processing and further corroborate the notion of social content as a distinct stimulus category.

Neurophysiological evidence for evaluative feedback processing depending on goal relevance

Feedback signaling the success or failure of actions is readily exploited to implement goal-directed behavior. Two event-related brain potentials (ERPs) have been identified as reliable markers of evaluative feedback processing: the Feedback-Related Negativity (FRN) and the P3. Recent ERP studies have shown a substantial reduction of these components when the feedback's goal relevance (in terms of goal informativeness) was decreased. However, it remains unclear whether this lowering of evaluative feedback processing at the FRN and P3 levels (i) reflects a common regulation process operating across them or (ii) indirectly and mostly depends on valence processing. To address these questions, 44 participants performed a time estimation task wherein the perceived goal relevance of the feedback following each decision was manipulated via instructions in different blocks. We recorded 64-channel EEG and collected subjective ratings of feedback valence and relevance, separately for goal-relevant and irrelevant conditions. ERP results showed a substantial reduction of the FRN and P3 components for irrelevant than relevant feedback, despite the balanced task relevance between them. Moreover, a Principal Component Analysis (PCA) showed that these two successive ERP effects had dissociable spatiotemporal properties. Crucially, a multivariate multiple regression analysis revealed that goal relevance per se, but not valence, was the unique significant predictor of the amplitude reduction of the FRN and P3 when the feedback was goal irrelevant. Our results suggest that although these ERP components exhibit non-overlapping spatiotemporal properties and performance monitoring effects, they can both be modulated by a common, valence-unspecific process related to goal relevance.

Social distance modulates the process of uncertain decision-making: evidence from event-related potentials

Purpose

Social distance affects risk perception in uncertain decision-making, but how this effect works and the mechanism of how social distance influences the early processing stages of uncertain decision-making are still unclear. This investigation aimed to explore how social distance influences risk-taking during uncertain decision-making using the Iowa Gambling Task with recording of event-related potentials.

Methods

A total of 57 healthy subjects (36 female) participated in the modified single-choice Iowa Gambling Task when they gambled based on three quantified social distances (self, friend, and stranger). The social distance between participant and beneficiary was quantified on a scale of 0–100 points, with 0 representing self, 5 representing a close friend, and 100 representing a stranger.

Results

Three stages of uncertain decision-making were analyzed. Behavioral results showed that social distance worked interactively with choice frame, and high social distance made people choose a more advantageous deck and a less disadvantageous deck than low social distance. The P300 in the choice-evaluation stage, which reflects stimulus discrimination, directly proved this result by showing that gambling for a stranger caused higher P300 when evaluating an advantageous deck and lower P300 when evaluating a disadvantageous deck than for others. Decision preceding negativity in the response-selection stage represents the anticipation of risky choices: this was larger with high social distance when choosing a disadvantageous deck. Feedback-related negativity and feedback-related P300 had motivational significance, showing smaller amplitudes when gambling for a stranger than for oneself.

Conclusion

These results provide evidence that social distance works interactively with choice frames of uncertain decision-making. People at high social distance are more risk-taking in an advantageous frame and more risk-avoid ant in a disadvantageous frame.

Cardiac cycle modulates reward feedback processing: An ERP study

The present study aimed to investigate whether the evaluative processing of action feedback is influenced by the cardiac cycle. To this aim, we examined the influence of the cardiac cycle on an event-related brain potential (ERP) effect that indexed the evaluative processing of action feedback [i.e., an ERP effect that interpreted as a feedback-related negativity (FRN) elicited by "bad" action feedback or a reward positivity (RewP) elicited by "good" action feedback]. Participants performed a gambling task in which they chose one of two stimuli and received an action feedback that indicated monetary gain or loss. Each trial was retrospectively classified into systole and diastole trials; systole trials were defined as those where monetary outcomes were presented during systole, and the diastole trials as those where monetary outcomes were presented during diastole. The results showed that the FRN/RewP was larger for the systole trials than for the diastole trials, which was due to the modulation of gain rather than loss ERPs. These results provide evidence that the natural fluctuation of cardiac afferent signals can modulate the evaluative processing of feedback.

The influence of context condition on outcome evaluation in experimental conditions: Even vs. neutral

Feedback-related negativity (FRN) is an event-related brain potential that is elicited during outcome evaluation. Studies have found that FRN reflects a good vs. bad classification; more importantly, FRN reflects this classification in a context-dependent manner, which means that the outcome evaluation is obviously influenced by its embedded context. In the current study, we examined how the context conditions of even (i.e., the feedback was +4 or -4) and neutral (i.e., the feedback was always 0) affect the outcome evaluation in experimental conditions (gain and loss). The experimental conditions of gain (i.e., the feedback was +4 or 0) and loss (i.e., the feedback was 0 or -4) were presented with the even condition as the context in one section and with the neutral condition as the context in another section. The ERP (event-related potential) results of the two experimental conditions showed that the unfavorable outcome evoked more negative FRN than the favorable outcome in both even and neutral sections, however, the amplitude difference between unfavorable and favorable outcomes was greater in neutral section than in even section. Furthermore, the favorable outcomes evoked more positive FRN in the neutral section than in the even section. These results indicate that the context condition modulates outcome evaluation, in neutral context, the discrimination between favorable and unfavorable outcome is better, which might due to the facilitated identification of favorable outcomes in neutral context.

Cultural influences on the processing of social comparison feedback signals-an ERP study

This study investigated cultural differences regarding social connectedness in association with social vs non-social comparison feedback. We performed electroencephalography in 54 Chinese and 49 Western adults while they performed a time estimation task in which response-accuracy feedback was either delivered pertaining to participants' own performance (non-social reference frame) or to the performance of a reference group (social reference frame). Trait interdependence and independence were assessed using a cultural orientations questionnaire. Applying a principal component approach, we observed divergent effects for the two cultural groups during feedback processing. In particular, Feedback-Related Negativity results indicated that non-social (vs social) reference feedback was more salient/motivating for Chinese participants, while Westerners showed the opposite pattern. The results suggest that Chinese individuals perceive a non-social context as more salient than a social comparison context, possibly due to their extensive experience of social comparisons in daily life. The reverse pattern was found in Western participants, for whom a social comparison context is less common and presumably more salient. The cultural differences in neural responses to social vs non-social feedback might be caused by culturally diverse cognitive traits, as well as by exposure to culturally defined behaviour on a systemic level-such as the education system.

Monetary Incentives Modulate Feedback-related Brain Activity

Previous research has shown that feedback evaluation is sensitive to monetary incentive. We investigated whether this sensitivity is driven by motivational salience (the difference between both rewarding and punishing events versus neutral events) or by motivational valence (the difference between rewarding and punishing events). Fifty-seven participants performed a monetary incentive delay task under a gain context, a loss context, and a neutral context with their electroencephalogram recorded. During the time domain, the feedback-related negativity (FRN) showed a motivational salience effect whereas the P3 displayed a reward valence effect. During the time-frequency domain, we observed a motivational salience effect for phase-locked theta power regardless of performance feedback, but a reward valence effect for non-phase-locked theta power in response to unsuccessful feedback. Moreover, we found a reward valence effect for phase-locked delta. These findings thus suggest that the affective modulation on feedback evaluation can be driven either by motivational valence or by motivational salience, which depends on the temporal dynamics (the FRN vs. the P3), the frequency dynamics (theta vs. delta power), as well as the phase dynamics (evoked vs. induced power).

Internal control beliefs and reference frame concurrently impact early performance monitoring ERPs

This study investigated the impact of criterion-based vs. social reference frames on behavioural and neural correlates of performance monitoring while taking individual differences in control beliefs into account. We conducted two experiments administering a time estimation task in which feedback was either delivered pertaining to participants’ own performance (nonsocial/criterion-based reference) or to the performance of a reference group of previous participants (social reference). In Experiment 1, 34 male volunteers participated. To test generalizability of the observed results to both sexes/genders, we recruited 36 female volunteers for Experiment 2. P2 and P300 amplitudes were generally larger in social than in nonsocial reference trials in the male participants of Experiment 1. ΔFRN amplitudes were larger for social compared to non-social reference trials in Experiment 1. No effects of reference frame were found in the female sample of Experiment 2. Rather, P2 and ΔFRN effects showed opposing patterns for nonsocial versus social reference frames. However, stronger internal control beliefs were accompanied by larger FRN amplitudes of negative social reference trials in both samples, suggesting generalizable effects independent of sex/gender. Enhanced P2 and ΔFRN amplitudes for social versus nonsocial reference trials suggest enhanced attentional capture and higher saliency of socially framed feedback in male participants only. In both sexes/genders, however, the social reference frame possibly challenges internal control beliefs and by this enhances performance monitoring. Our results demonstrate the complex interplay of trait variables and reference frames during performance monitoring influencing our daily lives-reference frames are omnipresent in education and one’s working environment.

Coercive and legitimate authority impact tax honesty: evidence from behavioral and ERP experiments

Cooperation in social systems such as tax honesty is of central importance in our modern societies. However, we know little about cognitive and neural processes driving decisions to evade or pay taxes. This study focuses on the impact of perceived tax authority and examines the mental chronometry mirrored in ERP data allowing a deeper understanding about why humans cooperate in tax systems. We experimentally manipulated coercive and legitimate authority and studied its impact on cooperation and underlying cognitive (experiment 1, 2) and neuronal (experiment 2) processes. Experiment 1 showed that in a condition of coercive authority, tax payments are lower, decisions are faster and participants report more rational reasoning and enforced compliance, however, less voluntary cooperation than in a condition of legitimate authority. Experiment 2 confirmed most results, but did not find a difference in payments or self-reported rational reasoning. Moreover, legitimate authority led to heightened cognitive control (expressed by increased MFN amplitudes) and disrupted attention processing (expressed by decreased P300 amplitudes) compared to coercive authority. To conclude, the neuronal data surprisingly revealed that legitimate authority may led to higher decision conflict and thus to higher cognitive demands in tax decisions than coercive authority.

Visual awareness negativity is an early neural correlate of awareness: A preregistered study with two Gabor sizes

Electrophysiological recordings are commonly used to study the neural correlates of consciousness in humans. Previous research is inconsistent as to whether awareness can be indexed with visual awareness negativity (VAN) at about 200 ms or if it occurs later. The present study was preregistered with two main aims: First, to provide independent evidence for or against the presence of VAN, and second, to study whether stimulus size may account for the inconsistent findings. Subjects were shown low-contrast Gaussian filtered gratings (Gabor patches) in the four visual quadrants. Gabor size (large and small) was varied in different sessions and calibrated to each subject's threshold of visual awareness. Event-related potentials were derived from trials in which subjects localized the Gabors correctly to capture the difference between trials in which they reported awareness versus no awareness. Bayesian analyses revealed very strong evidence for the presence of VAN for both Gabor sizes. However, there was no evidence for or against an effect of stimulus size. The present findings provide evidence for VAN as an early neural correlate of awareness.

Social dimension and complexity differentially influence brain responses during feedback processing

Recent research emphasizes the importance of social factors during performance monitoring. Thus, the current study investigated the impact of social stimuli -such as communicative gestures- on feedback processing. Moreover, it addressed a shortcoming of previous studies, which failed to consider stimulus complexity as potential confounding factor. Twenty-four volunteers performed a time estimation task while their electroencephalogram was recorded. Either social complex, social non-complex, non-social complex, or non-social non-complex stimuli were used to provide performance feedback. No effects of social dimension or complexity were found for task performance. In contrast, Feedback-Related Negativity (FRN) and P300 amplitudes were sensitive to both factors, with larger FRN and P300 amplitudes after social compared to non-social stimuli, and larger FRN amplitudes after complex positive than non-complex positive stimuli. P2 amplitudes were solely sensitive to feedback valence and social dimension. Subjectively, social complex stimuli were rated as more motivating than non-social complex ones. Independently of each other, social dimension and visual complexity influenced amplitude variation during performance monitoring. Social stimuli seem to be perceived as more salient, which is corroborated by P2, FRN and P300 results, as well as by subjective ratings. This could be explained due to their given relevance during every day social interactions.

Processing expected and unexpected uncertainty is modulated by fearless-dominance personality traits - An exploratory ERP study on feedback processing

Expectancy and certainty regarding an outcome are important factors during performance monitoring. However, the separate contributions of expected and unexpected uncertainty on different measures of performance monitoring, including feedback-related negativity (FRN) and P300 components, are not well established. The current study investigated their relationship to fearless-dominance, a personality construct described by high social potency and low anxiety. Accurately predicting environmental outcomes in certain and uncertain situations might be a prerequisite of social potency, therefore it may be associated with increased performance monitoring and its ERP correlates. Consequently, expected-uncertain and unexpected-uncertain feedback (by violating previously learned certain and expected feedback) was introduced in addition to expected-certain feedback in healthy individuals during a probabilistic gambling task. In both FRN and P300 components, difference waves were more pronounced for unexpected-uncertain and expected-uncertain compared to expected-certain feedback. Moreover, more fearless-dominant individuals showed diminished feedback processing specifically in expected-uncertain trials, but concurrently enhanced attentional processing in expected-certain trials. These findings indicate adaptive and situation-appropriate utilization of performance monitoring resources in individuals with more pronounced fearless-dominance personality traits. The results indicate that a precise differentiation of expected and unexpected uncertainty in fearless-dominant individuals is mandatory in order to better understand the underlying personality construct and related behavior.

Electrophysiological Correlates of Emotional Content and Volume Level in Spoken Word Processing

For visual stimuli of emotional content as pictures and written words, stimulus size has been shown to increase emotion effects in the early posterior negativity (EPN), a component of event-related potentials (ERPs) indexing attention allocation during visual sensory encoding. In the present study, we addressed the question whether this enhanced relevance of larger (visual) stimuli might generalize to the auditory domain and whether auditory emotion effects are modulated by volume. Therefore, subjects were listening to spoken words with emotional or neutral content, played at two different volume levels, while ERPs were recorded. Negative emotional content led to an increased frontal positivity and parieto-occipital negativity-a scalp distribution similar to the EPN-between ~370 and 530 ms. Importantly, this emotion-related ERP component was not modulated by differences in volume level, which impacted early auditory processing, as reflected in increased amplitudes of the N1 (80-130 ms) and P2 (130-265 ms) components as hypothesized. However, contrary to effects of stimulus size in the visual domain, volume level did not influence later ERP components. These findings indicate modality-specific and functionally independent processing triggered by emotional content of spoken words and volume level.