People matter: Perceived sender identity modulates cerebral processing of socio-emotional language feedback

How and when social evaluative feedback is processed in the brain: A systematic review on ERP studies

Social evaluative feedback informs the receiver of the other's views, which may contain judgments of personality-related traits and/or the level of likability. Such kinds of social evaluative feedback are of particular importance to humans. Event-related potentials (ERPs) can directly measure where in the processing stream feedback valence, expectancy, or contextual relevance modulate information processing. This review provides an overview and systematization of studies and early, mid-latency, and late ERP effects. Early effects were inconsistently reported for all factors. Feedback valence effects are more consistently reported for specific mid-latency ERPs (Reward Positivity, RewP, and Early Posterior Negativity, EPN) and late positivities (P3 and Late Positive Potential, LPP). Unexpected feedback consistently increased the Feedback Related Negativity (FRN) and, less consistently, decreased P3 amplitudes. Contextual relevance of the sender (e.g., human vs computer sender) or self-relatedness increased mid-latency to late ERPs. Interactions between valence and other factors were less often found, arising during mid-latency stages, where most consistent interactions showed larger EPN and P3 amplitude differences for valent feedback in a more relevant context. The ERP findings highlight that social evaluative feedback is consistently differentiated during mid-latency processing stages. The review discusses the relevance of findings, possible shortcomings of different experimental designs, and open questions. Furthermore, we suggest concrete venues for future research.

Nudging healthy food choices through e-messages in a supermarket

This paper analyses the impact of a healthy food nudge intervention on purchases of 1590 customers of a supermarket chain's loyalty program in Uruguay through a randomized controlled trial. Nudges were presented in the form of messages sent through WhatsApp to customers three times a week for 8 weeks (between July and September 2020). Messages highlighted the benefits of cooking at home and eating mindfully and healthy (vegetables, fruits, healthy snacks, legumes, and fish), and included easy to implement tips. Results show that, on average, customers assigned to the treatment group increased their purchases of healthy food by 8% and substituted sugar-sweetened for sugar-free beverages. We find an unintended increase in purchases of unhealthy food of 7%, with no correlative increase in calories, suggesting that customers substituted higher calorie products for lower calorie ones. We find that households with lower educational attainment, lower income, and with children under the age of 12 are more likely to increase purchases of fruits and vegetables, while other households are more likely to improve the diet quality without increasing expenditure. Effects do not persist after the intervention is over, suggesting that salience, rather than information is the main channel triggering the effects.

Dyadic cooperation with human and artificial agents: Event-related potentials trace dynamic role taking during an interactive game

Humans are highly co-operative and thus cognitively, affectively, and motivationally tuned to pursue shared goals. Yet, cooperative tasks typically require people to constantly take and switch individual roles. Task relevance is dictated by these roles and thereby dynamically changing. Here, we designed a dyadic game to test whether the family of P3 components can trace this dynamic allocation of task relevance. We demonstrate that late positive event-related potential (ERP) modulations not only reflect predictable asymmetries between receiving and sending information but also differentiate whether the receiver's role is related to correct decision making or action monitoring. Furthermore, similar results were observed when playing the game with a computer, suggesting that experimental games may motivate humans to similarly cooperate with an artificial agent. Overall, late positive ERP waves provide a real-time measure of how role taking dynamically shapes the meaning and relevance of stimuli within collaborative contexts. Our results, therefore, shed light on how the processes of mutual coordination unfold during dyadic cooperation.

Fear of negative evaluation modulates the processing of social evaluative feedback with different valence and contexts

Fear of negative evaluation (FNE) is a susceptible and maintaining factor of social anxiety disorders. However, the question, how people process negative evaluation is influenced by individual differences in FNE, is poorly understood. To clarify the habitual processing characteristics of individuals with different levels of FNE, electroencephalography was recorded when two groups of participants with high FNE (hFNE) and low FNE (lFNE) performed a social evaluation perception task in which the feedback context/source (human vs. a computer) and valence (thumb-up/like vs. thumb-down/dislike) were manipulated. We found effects of feedback source and valence on N1, P2, and P3, which reflect early attention, integrated perception, and elaborative processing, respectively, as well as general reward effects on reward positivity (RewP) across contexts. Importantly, compared to the lFNE group, the hFNE group showed larger midfrontal N1 and theta oscillation in response to negative feedback indicating dislike (vs. like), and also showed larger P3. These findings suggest that individuals with hFNE are more attentional vigilance to negative (vs. positive) social feedback, implying that individuals with different levels of FNE assign different implicit threat values to social-evaluation threat stimuli.

Encoding in a social feedback context enhances and biases behavioral and electrophysiological correlates of long-term recognition memory

Encoding often occurs in social contexts, yet research has hardly addressed their role in verbal memory. In three experiments, we investigated the behavioral and neural effects of encoding context on memory for positive, negative, and neutral adjectives, contrasting a social-feedback group (N = 24) with an explicit verbal-learning (N = 24) and a levels-of-processing group (N = 24). Participants in the social-feedback group were not aware of a recognition session one week later, but their memory was better than the explicit learning or the levels-of-processing groups'. However, they also exhibited the strongest response bias, particularly for positive words. Brain event-related potentials (ERPs) revealed largest early negativities (EPN) and late positivities (LPP) in the social-feedback group. Only in the subsequent slow-wave did the explicit learning group show higher amplitudes than the other two groups, suggesting reliance on strategic rather than automatic processes. Still, context-driven incidental encoding outweighed explicit instructions, specifying a decisive role of social factors in memory.

Feel Thine Own Self – Mood Congruency Evaluation of Emotional State Adjectives

Abstract. The goal of the study was to explore event-related potential (ERP) differences during the processing of emotional adjectives that were evaluated as congruent or incongruent with the current mood. We hypothesized that the first effects of congruence evaluation would be evidenced during the earliest stages of semantic analysis. Sixty mood adjectives were presented separately for 1,000 ms each during two sessions of mood induction. After each presentation, participants evaluated to what extent the word described their mood. The results pointed to incongruence marking of adjective’s meaning with current mood during early attention orientation and semantic access stages (the P150 component time window). This was followed by enhanced processing of congruent words at later stages. As a secondary goal the study also explored word valence effects and their relation to congruence evaluation. In this regard, no significant effects were observed on the ERPs; however, a negativity bias (enhanced responses to negative adjectives) was noted on the behavioral data (RTs), which could correspond to the small differences traced on the late positive potential.

Situating language in a minimal social context: how seeing a picture of the speaker's face affects language comprehension

Natural use of language involves at least two individuals. Some studies have focused on the interaction between senders in communicative situations and how the knowledge about the speaker can bias language comprehension. However, the mere effect of a face as a social context on language processing remains unknown. In the present study, we used event-related potentials to investigate the semantic and morphosyntactic processing of speech in the presence of a photographic portrait of the speaker. In Experiment 1, we show that the N400, a component related to semantic comprehension, increased its amplitude when processed within this minimal social context compared to a scrambled face control condition. Hence, the semantic neural processing of speech is sensitive to the concomitant perception of a picture of the speaker's face, even if irrelevant to the content of the sentences. Moreover, a late posterior negativity effect was found to the presentation of the speaker's face compared to control stimuli. In contrast, in Experiment 2, we found that morphosyntactic processing, as reflected in left anterior negativity and P600 effects, is not notably affected by the presence of the speaker's portrait. Overall, the present findings suggest that the mere presence of the speaker's image seems to trigger a minimal communicative context, increasing processing resources for language comprehension at the semantic level.

Mood Induction Differently Affects Early Neural Correlates of Evaluative Word Processing in L1 and L2

We investigate how mood inductions impact the neural processing of emotional adjectives in one's first language (L1) and a formally acquired second language (L2). Twenty-three student participants took part in an EEG experiment with two separate sessions. Happy or sad mood inductions were followed by series of individually presented positive, negative, or neutral adjectives in L1 (German) or L2 (English) and evaluative decisions had to be performed. Visual event-related potentials elicited during word processing were analyzed during N1 (125-200 ms), Early Posterior Negativities (EPN, 200-300 ms and 300-400 ms), N400 (350-450 ms), and the Late Positive Potential (LPP, 500-700 ms). Mood induction differentially impacted word processing already on the N1, with stronger left lateralization following happy than sad mood induction in L1, but not in L2. Moreover, regardless of language, early valence modulation was found following happy but not sad mood induction. Over occipital areas, happy mood elicited larger amplitudes of the mood-congruent positive words, whereas over temporal areas mood-incongruent negative words had higher amplitudes. In the EPN-windows, effects of mood and valence largely persisted, albeit with no difference between L1 and L2. N400 amplitude was larger for L2 than for L1. On the LPP, mood-incongruent adjectives elicited larger amplitudes than mood-congruent ones. Results reveal a remarkably early valence-general effect of mood induction on cortical processing, in line with previous reports of N1 as a first marker of contextual integration. Interestingly, this effect differed between L1 and L2. Moreover, mood-congruent effects were found in perceptual processing and mood-incongruent ERP amplification in higher-order evaluative stages.

Oscillatory EEG Signatures of Affective Processes during Interaction with Adaptive Computer Systems

Affect monitoring is being discussed as a novel strategy to make adaptive systems more user-oriented. Basic knowledge about oscillatory processes and functional connectivity underlying affect during naturalistic human-computer interactions (HCI) is, however, scarce. This study assessed local oscillatory power entrainment and distributed functional connectivity in a close-to-naturalistic HCI-paradigm. Sixteen participants interacted with a simulated assistance system which deliberately evoked positive (supporting goal-achievement) and negative (impeding goal-achievement) affective reactions. Electroencephalography (EEG) was used to examine the reactivity of the cortical system during the interaction by studying both event-related (de-)synchronization (ERD/ERS) and event-related functional coupling of cortical networks towards system-initiated assistance. Significantly higher α-band and β-band ERD in centro-parietal and parieto-occipital regions and β-band ERD in bi-lateral fronto-central regions were observed during impeding system behavior. Supportive system behavior activated significantly higher γ-band ERS in bi-hemispheric parietal-occipital regions. This was accompanied by functional coupling of remote β-band and γ-band activity in the medial frontal, left fronto-central and parietal regions, respectively. Our findings identify oscillatory signatures of positive and negative affective processes as reactions to system-initiated assistance. The findings contribute to the development of EEG-based neuroadaptive assistance loops by suggesting a non-obtrusive method for monitoring affect in HCI.

Attributed social context and emotional content recruit frontal and limbic brain regions during virtual feedback processing

In communication, who is communicating can be just as important as what is said. However, sender identity in virtual communication is often inferred rather than perceived. Therefore, the present research investigates the brain structures activated by sender identity attributions and evaluative feedback processing during virtual communication. In a functional magnetic resonance imaging (fMRI) study, 32 participants were told that they would receive personality feedback, either sent from another human participant or from a randomly acting computer. In reality, both conditions contained random but counterbalanced feedback, automatically delivered by approving or denying negative, neutral, or positive adjectives. Although physically identical, feedback attributed to the "human" sender activated multiple regions within a "social brain" network, including the superior frontal, medial prefrontal, and orbitofrontal cortex, anterior and posterior parts of the cingulate cortex, and the bilateral insula. Regardless of attributed sender, positive feedback increased responses in the striatum and bilateral amygdalae, while negative compared to neutral feedback elicited stronger insula and somatosensory responses. These results reveal the recruitment of an extensive mentalizing and social brain network by mere sender attributions and the activation of brain structures related to reward and punishment by verbal feedback, demonstrating its embodied processing.

Attending to Eliza: rapid brain responses reflect competence attribution in virtual social feedback processing

In the age of virtual communication, the source of a message is often inferred rather than perceived, raising the question of how sender attributions affect content processing. We investigated this issue in an evaluative feedback scenario. Participants were told that an expert psychotherapist, a layperson or a randomly acting computer was going to give them online positive, neutral or negative personality feedback while high-density EEG was recorded. Sender attribution affected processing rapidly, even though the feedback was on average identical. Event-related potentials revealed a linear increase with attributed expertise beginning 150 ms after disclosure and most pronounced for N1, P2 and early posterior negativity components. P3 and late positive potential amplitudes were increased for both human senders and for emotionally significant (positive or negative) feedback. Strikingly, feedback from a putative expert prompted large P3 responses, even for inherently neutral content. Source analysis localized early enhancements due to attributed sender expertise in frontal and somatosensory regions and later responses in the posterior cingulate and extended visual and parietal areas, supporting involvement of mentalizing, embodied processing and socially motivated attention. These findings reveal how attributed sender expertise rapidly alters feedback processing in virtual interaction and have implications for virtual therapy and online communication.

The effect of emotional and self-referential contexts on ERP responses towards surprised faces

The perception of surprised faces is demonstrably modulated by emotional context. However, the influence of self-relevance and its interaction with emotional context have not been explored. The present study investigated the effects of contextual valence and self-reference on the perception of surprised faces. Our results revealed that faces in a negative context elicited a larger N170 than those in a neutral context. The EPN was affected by the interaction between contextual valence and self-reference, with larger amplitudes for faces in self-related positive contexts and sender-related negative contexts. Additionally, LPP amplitudes were enhanced for faces in negative contexts relative to neutral and positive contexts, as well as for self-related contexts in comparison to sender-related contexts. Together, these findings help to elucidate the psychophysiological mechanisms underlying the effects of emotional and self-referential contexts on the perception of surprised faces, which are characterized by distinctive ERPs.

Dissociating neural signatures of mental state retrodiction and classification based on facial expressions

Posed facial expressions of actors have often been used as stimuli to induce mental state inferences, in order to investigate ‘Theory of Mind’ processes. However, such stimuli make it difficult to determine whether perceivers are using a basic or more elaborated mentalizing strategy. The current study used as stimuli covert recordings of target individuals who viewed various emotional expressions, which caused them to spontaneously mimic these expressions. Perceivers subsequently judged these subtle emotional expressions of the targets: in one condition (‘classification’) participants were instructed to classify the target’s expression (i.e. match it to a sample) and in another condition (‘retrodicting’) participants were instructed to retrodict (i.e. infer which emotional expression the target was viewing). When instructed to classify, participants showed more prevalent activations in event-related brain potentials (ERPs) at earlier and mid-latency ERP components N170, P200 and P300–600. By contrast, when instructed to retrodict participants showed enhanced late frontal and fronto-temporal ERPs (N800–1000), with more sustained activity over the right than the left hemisphere. These findings reveal different cortical processes involved when retrodicting about a facial expression compared to merely classifying it, despite comparable performance on the behavioral task.

Emotion in Context: How Sender Predictability and Identity Affect Processing of Words as Imminent Personality Feedback

Recent findings suggest that communicative context affects the timing and magnitude of emotion effects in word processing. In particular, social attributions seem to be one important source of plasticity for the processing of affectively charged language. Here, we investigate the timing and magnitude of ERP responses toward positive, neutral, and negative trait adjectives during the anticipation of putative socio-evaluative feedback from different senders (human and computer) varying in predictability. In the first experiment, during word presentation participants could not anticipate whether a human or a randomly acting computer sender was about to give feedback. Here, a main effect of emotion was observed only on the late positive potential (LPP), showing larger amplitudes for positive compared to neutral adjectives. In the second study the same stimuli and set-up were used, but a block-wise presentation was realized, resulting in fixed and fully predictable sender identity. Feedback was supposedly given by an expert (psychotherapist), a layperson (unknown human), and again by a randomly acting computer. Main effects of emotion started with an increased P1 for negative adjectives, followed by effects at the N1 and early posterior negativity (EPN), showing both largest amplitudes for positive words, as well as for the LPP, where positive and negative words elicited larger amplitudes than neutral words. An interaction revealed that emotional LPP modulations occurred only for a human sender. Finally, regardless of content, anticipating human feedback led to larger P1 and P3 components, being highest for the putative expert. These findings demonstrate the malleability of emotional language processing by social contexts. When clear predictions can be made, our brains rapidly differentiate between emotional and neutral information, as well as between different senders. Attributed human presence affects emotional language processing already during feedback anticipation, in line with a selective gating of attentional resources via anticipatory social significance attributions. By contrast, emotion effects occur much later, when crucial social context information is still missing. These findings demonstrate the context-dependence of emotion effects in word processing and are particularly relevant since virtual communication with unknown senders, whose identity is inferred rather than perceived, has become reality for millions of people.

An event-related potential comparison of facial expression processing between cartoon and real faces

Faces play important roles in the social lives of humans. Besides real faces, people also encounter numerous cartoon faces in daily life which convey basic emotional states through facial expressions. Using event-related potentials (ERPs), we conducted a facial expression recognition experiment with 17 university students to compare the processing of cartoon faces with that of real faces. This study used face type (real vs. cartoon), emotion valence (happy vs. angry) and participant gender (male vs. female) as independent variables. Reaction time, recognition accuracy, and the amplitudes and latencies of emotion processing-related ERP components such as N170, VPP (vertex positive potential), and LPP (late positive potential) were used as dependent variables. The ERP results revealed that cartoon faces caused larger N170 and VPP amplitudes as well as a briefer N170 latency than did real faces; that real faces induced larger LPP amplitudes than did cartoon faces. In addition, the results showed a significant difference in the brain regions as reflected in a right hemispheric advantage. The behavioral results showed that the reaction times for happy faces were shorter than those for angry faces; that females showed a higher accuracy than did males; and that males showed a higher recognition accuracy for angry faces than happy faces. Due to the sample size, these results may suggestively but not rigorously demonstrate differences in facial expression recognition and neurological processing between cartoon faces and real faces. Cartoon faces showed a higher processing intensity and speed than real faces during the early processing stage. However, more attentional resources were allocated for real faces during the late processing stage.

Verbal instructions override the meaning of facial expressions

Psychological research has long acknowledged that facial expressions can implicitly trigger affective psychophysiological responses. However, whether verbal information can alter the meaning of facial emotions and corresponding response patterns has not been tested. This study examined emotional facial expressions as cues for instructed threat-of-shock or safety, with a focus on defensive responding. In addition, reversal instructions were introduced to test the impact of explicit safety instructions on fear extinction. Forty participants were instructed that they would receive unpleasant electric shocks, for instance, when viewing happy but not angry faces. In a second block, instructions were reversed (e.g., now angry faces cued shock). Happy, neutral, and angry faces were repeatedly presented, and auditory startle probes were delivered in half of the trials. The defensive startle reflex was potentiated for threat compared to safety cues. Importantly, this effect occurred regardless of whether threat was cued by happy or angry expressions. Although the typical pattern of response habituation was observed, defense activation to newly instructed threat cues remained significantly enhanced in the second part of the experiment, and it was more pronounced in more socially anxious participants. Thus, anxious individuals did not exhibit more pronounced defense activation compared to less anxious participants, but their defense activation was more persistent.

The right touch: Stroking of CT-innervated skin promotes vocal emotion processing

Research has revealed a special mechanoreceptor, called C-tactile (CT) afferent, that is situated in hairy skin and that seems relevant for the processing of social touch. We pursued a possible role of this receptor in the perception of other social signals such as a person’s voice. Participants completed three sessions in which they heard surprised and neutral vocal and nonvocal sounds and detected rare sound repetitions. In a given session, participants received no touch or soft brushstrokes to the arm (CT innervated) or palm (CT free). Event-related potentials elicited to sounds revealed that stroking to the arm facilitated the integration of vocal and emotional information. The late positive potential was greater for surprised vocal relative to neutral vocal and nonvocal sounds, and this effect was greater for arm touch relative to both palm touch and no touch. Together, these results indicate that stroking to the arm facilitates the allocation of processing resources to emotional voices, thus supporting the possibility that CT stimulation benefits social perception cross-modally.

Pupillary Responses to Robotic and Human Emotions: The Uncanny Valley and Media Equation Confirmed

Physiological responses during human–robots interaction are useful alternatives to subjective measures of uncanny feelings for nearly humanlike robots (uncanny valley) and comparable emotional responses between humans and robots (media equation). However, no studies have employed the easily accessible measure of pupillometry to confirm the uncanny valley and media equation hypotheses, evidence in favor of the existence of these hypotheses in interaction with emotional robots is scarce, and previous studies have not controlled for low level image statistics across robot appearances. We therefore recorded pupil size of 40 participants that viewed and rated pictures of robotic and human faces that expressed a variety of basic emotions. The robotic faces varied along the dimension of human likeness from cartoonish to humanlike. We strictly controlled for confounding factors by removing backgrounds, hair, and color, and by equalizing low level image statistics. After the presentation phase, participants indicated to what extent the robots appeared uncanny and humanlike, and whether they could imagine social interaction with the robots in real life situations. The results show that robots rated as nearly humanlike scored higher on uncanniness, scored lower on imagined social interaction, evoked weaker pupil dilations, and their emotional expressions were more difficult to recognize. Pupils dilated most strongly to negative expressions and the pattern of pupil responses across emotions was highly similar between robot and human stimuli. These results highlight the usefulness of pupillometry in emotion studies and robot design by confirming the uncanny valley and media equation hypotheses.

ERP correlates of motivating voices: quality of motivation and time-course matters

Here, we conducted the first study to explore how motivations expressed through speech are processed in real-time. Participants listened to sentences spoken in two types of well-studied motivational tones (autonomy-supportive and controlling), or a neutral tone of voice. To examine this, listeners were presented with sentences that either signaled motivations through prosody (tone of voice) and words simultaneously (e.g. ‘You absolutely have to do it my way’ spoken in a controlling tone of voice), or lacked motivationally biasing words (e.g. ‘Why don’t we meet again tomorrow’ spoken in a motivational tone of voice). Event-related brain potentials (ERPs) in response to motivations conveyed through words and prosody showed that listeners rapidly distinguished between motivations and neutral forms of communication as shown in enhanced P2 amplitudes in response to motivational when compared with neutral speech. This early detection mechanism is argued to help determine the importance of incoming information. Once assessed, motivational language is continuously monitored and thoroughly evaluated. When compared with neutral speech, listening to controlling (but not autonomy-supportive) speech led to enhanced late potential ERP mean amplitudes, suggesting that listeners are particularly attuned to controlling messages. The importance of controlling motivation for listeners is mirrored in effects observed for motivations expressed through prosody only. Here, an early rapid appraisal, as reflected in enhanced P2 amplitudes, is only found for sentences spoken in controlling (but not autonomy-supportive) prosody. Once identified as sounding pressuring, the message seems to be preferentially processed, as shown by enhanced late potential amplitudes in response to controlling prosody. Taken together, results suggest that motivational and neutral language are differentially processed; further, the data suggest that listening to cues signaling pressure and control cannot be ignored and lead to preferential, and more in-depth processing mechanisms.

It's not me, it's you - Differential neural processing of social and non-social nogo cues in joint action

This study used a joint flanker task to investigate differences in processing of social and non-social nogo cues, i.e., between cues indicating that a co-actor should respond and cues signaling that neither actor nor co-actor should respond, using event-related potentials (ERPs) and trial-to-trial response times (RTs). It was hypothesized that a social co-actor's response should be reflected in stronger modulation (slower RTs on subsequent trials; augmented neural responses) for social compared to non-social nogo. RTs and ERPs replicated flanker compatibility effects, with faster responses and increased P3a on compatible trials. In line with the hypotheses, ERPs revealed distinct coding of social and non-social nogo in the conflict-sensitive N2 which showed a compatibility effect only for social nogo, and in the attention/memory-related P3b which was larger for social relative to non-social nogo. The P3a did not distinguish between social and non-social nogo, but was larger for compatible and smaller for go trials. Contrary to our hypotheses, RTs were faster after social relative to non-social nogo. Hence, the representation of the co-actor's response in joint action modulates conflict processing reflected in the N2 and response discrimination and evaluation reflected in the P3b and may facilitate subsequent responses in the context of social versus non-social nogo.

Empathy, Pain and Attention: Cues that Predict Pain Stimulation to the Partner and the Self Capture Visual Attention

Empathy motivates helping and cooperative behaviors and plays an important role in social interactions and personal communication. The present research examined the hypothesis that a state of empathy guides attention towards stimuli significant to others in a similar way as to stimuli relevant to the self. Sixteen couples in romantic partnerships were examined in a pain-related empathy paradigm including an anticipation phase and a stimulation phase. Abstract visual symbols (i.e., arrows and flashes) signaled the delivery of a Pain or Nopain stimulus to the partner or the self while dense sensor event-related potentials (ERPs) were simultaneously recorded from both persons. During the anticipation phase, stimuli predicting Pain compared to Nopain stimuli to the partner elicited a larger early posterior negativity (EPN) and late positive potential (LPP), which were similar in topography and latency to the EPN and LPP modulations elicited by stimuli signaling pain for the self. Noteworthy, using abstract cue symbols to cue Pain and Nopain stimuli suggests that these effects are not driven by perceptual features. The findings demonstrate that symbolic stimuli relevant for the partner capture attention, which implies a state of empathy to the pain of the partner. From a broader perspective, states of empathy appear to regulate attention processing according to the perceived needs and goals of the partner.

Differential effects of face-realism and emotion on event-related brain potentials and their implications for the uncanny valley theory

Cartoon characters are omnipresent in popular media. While few studies have scientifically investigated their processing, in computer graphics, efforts are made to increase realism. Yet, close approximations of reality have been suggested to evoke sometimes a feeling of eeriness, the “uncanny valley” effect. Here, we used high-density electroencephalography to investigate brain responses to professionally stylized happy, angry, and neutral character faces. We employed six face-stylization levels varying from abstract to realistic and investigated the N170, early posterior negativity (EPN), and late positive potential (LPP) event-related components. The face-specific N170 showed a u-shaped modulation, with stronger reactions towards both most abstract and most realistic compared to medium-stylized faces. For abstract faces, N170 was generated more occipitally than for real faces, implying stronger reliance on structural processing. Although emotional faces elicited highest amplitudes on both N170 and EPN, on the N170 realism and expression interacted. Finally, LPP increased linearly with face realism, reflecting activity increase in visual and parietal cortex for more realistic faces. Results reveal differential effects of face stylization on distinct face processing stages and suggest a perceptual basis to the uncanny valley hypothesis. They are discussed in relation to face perception, media design, and computer graphics.

Processing of fair and unfair offers in the ultimatum game under social observation

Social context influences social decisions and outcome processing, partially depending on inter-individual differences. The present study investigated social context-dependent modulation of behavior and feedback processing in the ultimatum game (UG) in relation to inter-individual differences in social anxiety. Thirty-two healthy adults completed the UG both under social observation and without observation. Offers were allegedly either randomly generated by the computer or drawn from a pool of offers from previous human players. Overall, fewer unfair than fair offers were accepted. Observation decreased acceptance rates for unfair offers. The feedback-locked feedback-related negativity (FRN) but not the P3 was modulated by observation and fairness, with stronger differential coding of unfair/fair under observation. This effect was strongly correlated with individual levels of social anxiety, with higher levels associated with stronger differential fairness coding in the FRN under observation. Behavioral findings support negative reciprocity in the UG, suggesting that (implicit) social norms overwrite explicit task instructions even in the absence of (alleged) social interaction. Observation enhances this effect. Fairness coding in the FRN was modulated by observation as a function of social anxiety, supporting the notion that altered sensitivity to equality in a social context may contribute to social avoidance in socially anxious individuals.

Selective visual attention to emotional words: Early parallel frontal and visual activations followed by interactive effects in visual cortex

Human brains spontaneously differentiate between various emotional and neutral stimuli, including written words whose emotional quality is symbolic. In the electroencephalogram (EEG), emotional-neutral processing differences are typically reflected in the early posterior negativity (EPN, 200-300 ms) and the late positive potential (LPP, 400-700 ms). These components are also enlarged by task-driven visual attention, supporting the assumption that emotional content naturally drives attention. Still, the spatio-temporal dynamics of interactions between emotional stimulus content and task-driven attention remain to be specified. Here, we examine this issue in visual word processing. Participants attended to negative, neutral, or positive nouns while high-density EEG was recorded. Emotional content and top-down attention both amplified the EPN component in parallel. On the LPP, by contrast, emotion and attention interacted: Explicit attention to emotional words led to a substantially larger amplitude increase than did explicit attention to neutral words. Source analysis revealed early parallel effects of emotion and attention in bilateral visual cortex and a later interaction of both in right visual cortex. Distinct effects of attention were found in inferior, middle and superior frontal, paracentral, and parietal areas, as well as in the anterior cingulate cortex (ACC). Results specify separate and shared mechanisms of emotion and attention at distinct processing stages. Hum Brain Mapp 37:3575-3587, 2016. © 2016 Wiley Periodicals, Inc.

Uninstructed BIAT faking when ego depleted or in normal state: differential effect on brain and behavior

BACKGROUND

Deception can distort psychological tests on socially sensitive topics. Understanding the cerebral processes that are involved in such faking can be useful in detection and prevention of deception. Previous research shows that faking a brief implicit association test (BIAT) evokes a characteristic ERP response. It is not yet known whether temporarily available self-control resources moderate this response. We randomly assigned 22 participants (15 females, 24.23 ± 2.91 years old) to a counterbalanced repeated-measurements design. Participants first completed a Brief-IAT (BIAT) on doping attitudes as a baseline measure and were then instructed to fake a negative doping attitude both when self-control resources were depleted and non-depleted. Cerebral activity during BIAT performance was assessed using high-density EEG.

RESULTS

Compared to the baseline BIAT, event-related potentials showed a first interaction at the parietal P1, while significant post hoc differences were found only at the later occurring late positive potential. Here, significantly decreased amplitudes were recorded for 'normal' faking, but not in the depletion condition. In source space, enhanced activity was found for 'normal' faking in the bilateral temporoparietal junction. Behaviorally, participants were successful in faking the BIAT successfully in both conditions.

CONCLUSIONS

Results indicate that temporarily available self-control resources do not affect overt faking success on a BIAT. However, differences were found on an electrophysiological level. This indicates that while on a phenotypical level self-control resources play a negligible role in deliberate test faking the underlying cerebral processes are markedly different.