Associated valence impacts early visual processing of letter strings: Evidence from ERPs in a cross-modal learning paradigm

The influence of word concreteness on acquired positive emotion association: An event-related potential study

The ability to acquire positive emotions from words is essential to psychological well-being. How word concreteness affects the process of positive emotion acquisition remains unknown. Here, using an evaluation conditioning paradigm, participants learned the association between pseudowords and concrete/abstract and positive/neutral words. Behavior and event-related potential data were recorded while participants performed emotional recognition tasks. Behavioral results showed that, for neutral words, concrete words were more accurate than abstract words, whereas for positive words, abstract words were more accurate than concrete words. Moreover, N1 and P2 amplitudes in the pseudowords were modulated by interacting word emotion and concreteness. Specifically, pseudowords associated with neutral concrete words elicited larger N1 and P2 amplitudes than pseudowords associated with neutral abstract words. Conversely, N1 and P2 amplitudes in pseudowords associated with positive abstract words were not significant compared to those in positive concrete words. Additionally, an emotional effect was observed when pseudowords were associated with abstract words, showing higher P3 amplitude for the pseudowords associated with positive abstract words than neutral abstract words. No significant effects were found for the pseudowords associated with positive abstract or concrete words. These findings suggest that association learning may influence the early attention processing of emotion acquisition from words, and emotional information of positive abstract words might boost positive emotion acquisition, thereby eliminating the acquisition advantage from positive concrete words.

Motivated attention and task relevance in the processing of cross-modally associated faces: Behavioral and electrophysiological evidence

It has repeatedly been shown that visually presented stimuli can gain additional relevance by their association with affective stimuli. Studies have shown effects of associated affect in event-related potentials (ERP) like the early posterior negativity (EPN), late positive complex (LPC), and even earlier components as the P1 or N170. However, findings are mixed as to the extent associated affect requires directed attention to the emotional quality of a stimulus and which ERP components are sensitive to task instructions during retrieval. In this preregistered study ( https://osf.io/ts4pb ), we tested cross-modal associations of vocal affect-bursts (positive, negative, neutral) to faces displaying neutral expressions in a flash-card-like learning task, in which participants studied face-voice pairs and learned to correctly assign them to each other. In the subsequent EEG test session, we applied both an implicit ("old-new") and explicit ("valence-classification") task to investigate whether the behavior at retrieval and neurophysiological activation of the affect-based associations were dependent on the type of motivated attention. We collected behavioral and neurophysiological data from 40 participants who reached the preregistered learning criterium. Results showed EPN effects of associated negative valence after learning and independent of the task. In contrast, modulations of later stages (LPC) by positive and negative associated valence were restricted to the explicit, i.e., valence-classification, task. These findings highlight the importance of the task at different processing stages and show that cross-modal affect can successfully be associated to faces.

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.

Differential effects of intra-modal and cross-modal reward value on perception: ERP evidence

In natural environments objects comprise multiple features from the same or different sensory modalities but it is not known how perception of an object is affected by the value associations of its constituent parts. The present study compares intra- and cross-modal value-driven effects on behavioral and electrophysiological correlates of perception. Human participants first learned the reward associations of visual and auditory cues. Subsequently, they performed a visual discrimination task in the presence of previously rewarded, task-irrelevant visual or auditory cues (intra- and cross-modal cues, respectively). During the conditioning phase, when reward associations were learned and reward cues were the target of the task, high value stimuli of both modalities enhanced the electrophysiological correlates of sensory processing in posterior electrodes. During the post-conditioning phase, when reward delivery was halted and previously rewarded stimuli were task-irrelevant, cross-modal value significantly enhanced the behavioral measures of visual sensitivity, whereas intra-modal value produced only an insignificant decrement. Analysis of the simultaneously recorded event-related potentials (ERPs) of posterior electrodes revealed similar findings. We found an early (90-120 ms) suppression of ERPs evoked by high-value, intra-modal stimuli. Cross-modal stimuli led to a later value-driven modulation, with an enhancement of response positivity for high- compared to low-value stimuli starting at the N1 window (180-250 ms) and extending to the P3 (300-600 ms) responses. These results indicate that sensory processing of a compound stimulus comprising a visual target and task-irrelevant visual or auditory cues is modulated by the reward value of both sensory modalities, but such modulations rely on distinct underlying mechanisms.

On the dynamics of gain and loss: Electrophysiological evidence from associative learning

Associated relevance affects the sensory encoding of low-level visual features of symbolic stimuli. It is unclear, however, which dimension of low-level visual features benefits from prioritized processing, and how these effects develop throughout the course of relevance acquisition. Moreover, previous evidence is inconclusive regarding the preservation of processing advantage once the association is no longer relevant, as well as its generalization to perceptually similar but novel stimuli. The present study addresses these questions by employing an associative learning paradigm. In two experiments (N = 24 each, between-subject design), different dimensions of low-level visual features of symbolic stimuli were associated with monetary gain, loss, or zero outcome. In a consecutive old/new decision task, associated stimuli were presented together with perceptually similar but novel stimuli. Event-related brain potentials (P1, EPN, LPC) were measured throughout both sessions. Early sensory encoding (P1) was boosted by loss association and appeared to be sensitive to the dimension of the associated low-level visual features. Gain association influenced post-perceptual processing stages (LPC), arising over the course of the learning phase, and are preserved even when the associated outcome was no longer relevant. Gain association also resulted in EPN modulations similar to the effects observed in the case of emotional words. None of the observed effects generalized to perceptually similar stimuli. These results show that acquired relevance can influence the sensory processing of specific dimensions of low-level visual features. Moreover, this study extends previous evidence of a dissociation of early and late neural effects of associated motivational relevance.

Attentional tuning of valent word forms

Using event-related brain potentials (ERPs), we tested the hypothesis of valent word forms (Kissler et al., 2006, Prog Brain Res) stating that the mere visual shapes of emotional words acquire valence through numerous co-occurrences with affective activation over an experienced reader's life. Thereby, associations between neuronal representations of visual word forms and affect are strengthened. If so, selective attention to a specific level of the valence of single visual words should not only pre-activate neuronal representations of that level of valence, but this activation should also spread to the associated word forms. This should improve their processing and/or affective discrimination. In a valence-detection task, N = 53 participants made speeded responses only to words of the current target level of valence (negative, neutral, or positive), which varied across separate blocks. We focused on posterior visual P1 and N170 components, two well-established ERP markers of low-level and structural word form processing, respectively. P1 increased from negative over neutral to positive words; this effect was stronger in target compared to nontarget words. N170 was larger for emotional compared to neutral target words, whereas nontarget words showed a strong reverse pattern. The P1 effect for target words and the N170 effect for nontarget words both were driven by good task performers in terms of fast hit responses. Results support the idea of valent word forms that can be tuned by selective attention to valence, which implies both, facilitated affective discrimination and processing of target words, and inhibition of the processing of nontarget words.

Association between eating behavior and the immediate neural activity caused by viewing food images presented in and out of awareness: A magnetoencephalography study

Obesity is a serious health problem in modern society. Considering the fact that the outcomes of treatments targeting appetitive behavior are suboptimal, one potential reason proposed for these poor outcomes is that appetitive behavior is driven more by unconscious decision-making processes than by the conscious ones targeted by traditional behavioral treatments. In this study, we aimed to investigate both the conscious and unconscious decision-making processes related to eating behavior, and to examine whether an interaction related to eating behavior exists between conscious and unconscious neural processes. The study was conducted on healthy male volunteers who viewed pictures of food and non-food items presented both above and below the awareness threshold. The oscillatory brain activity affected by viewing the pictures was assessed by magnetoencephalography. A visual backward masking procedure was used to present the pictures out of awareness. Neural activity corresponding to the interactions between sessions (i.e., food or non-food) and conditions (i.e., visible or invisible) was observed in left Brodmann's areas 45 and 47 in the high-gamma (60-200 Hz) frequency range. The interactions were associated with eating behavior indices such as emotional eating and cognitive restraint, suggesting that conscious and unconscious neural processes are differently involved in eating behavior. These findings provide valuable clues for devising methods to assess conscious and unconscious appetite regulation in individuals with normal or abnormal eating behavior.

A Comparative Study on the Temporal Effects of 2D and VR Emotional Arousal

Previous research comparing traditional two-dimensional (2D) and virtual reality with stereoscopic vision (VR-3D) stimulations revealed that VR-3D resulted in higher levels of immersion. However, the effects of these two visual modes on emotional stimulus processing have not been thoroughly investigated, and the underlying neural processing mechanisms remain unclear. Thus, this paper introduced a cognitive psychological experiment that was conducted to investigate how these two visual modes influence emotional processing. To reduce fatigue, participants (n = 16) were randomly assigned to watch a series of 2D and VR-3D short emotional videos for two days. During their participation, electroencephalograms (EEG) were recorded simultaneously. The results showed that even in the absence of sound, visual stimuli in the VR environment significantly increased emotional arousal, especially in the frontal region, parietal region, temporal region, and occipital region. On this basis, visual evoked potential (VEP) analysis was performed. VR stimulation compared to 2D led to a larger P1 component amplitude, while VEP analysis based on the time course of the late event-related potential component revealed that, after 1200 ms, the differences across visual modes became stable and significant. Furthermore, the results also confirmed that VEP in the early stages is more sensitive to emotions and presumably there are corresponding emotion regulation mechanisms in the late stages.

Attention to affect 2.0: Multiple effects of emotion and attention on event-related potentials of visual word processing in a valence-detection task

Here we continue recent work on the specific mental processes engaged in a valence-detection task. Fifty-seven participants responded to one predefined target level of valence (negative, neutral, or positive), and ignored the remaining two levels. This enables more precise fine-tuning of neuronal pathways, compared to valence categorization where attention is divided between different levels of valence. Our group recently used valence detection with emotional words. Posterior P1 and N170 effects in the event-related potential (ERP) supported the idea of valent word forms that can be tuned by selective attention to valence. Here we report findings on three distinct posterior N2 components, P300, N400, and the late positive potential (LPP). Target but not nontarget words showed an arousal effect (emotional > neutral) on left-side early posterior negativity (180-280 ms). In contrast, an arousal effect on a sharp N2 deflection in left-minus-right difference ERPs (230-270 ms), suggesting facilitation of lexical access for emotional words, was independent of target status. This also applied to increased medial parieto-occipital N2 (260-300 ms) specific to negative words, indicating attentional capture. Medial-central N400 was specifically enhanced for negative nontarget words, further supporting attentional capture. The typical LPP arousal effect was observed, being stronger and more left-lateralized in target words. An exploratory finding concerned a broad component-overarching ERP valence effect (250-650 ms). Independent of target status, ERPs were more positive for positive than negative words. Combined with our previous results, data suggest multiple loci of emotion-attention interactions in valence detection.

Enhanced spontaneous retrieval of cues from emotional events: An ERP study

Recent evidence points to enhanced episodic memory retrieval not only for emotional items but also for neutral information encoded in emotional contexts. However, prior research only tested instructed explicit recognition, and hence here we investigated whether memory retrieval is also heightened for cues from emotional contexts when retrieval is not explicitly probed. During the first session of a two-session experiment, neutral objects were presented on different background scenes varying in emotional and neutral contents. One week later, objects were presented again (with no background) intermixed with novel objects. In both sessions, participants were instructed to attentively watch the stimuli (free viewing procedure), and during the second session, ERPs were also collected to measure the ERP Old/New effect, an electrophysiological correlate of episodic memory retrieval. Analyses were performed using cluster-based permutation tests in order to identify reliable spatio-temporal ERP differences. Based on this approach, old relative to new objects, were associated with larger ERP positivity in an early (364-744 ms) and late time window (760-1148 ms) over distinct central electrode clusters. Interestingly, significant late ERP Old/New differences were only observed for objects previously encoded with emotional, but not neutral scenes (504 to 1144 ms). Because these ERP differences were observed in a non-instructed retrieval context, our results indicate that long-term, spontaneous retrieval for neutral objects, is particularly heightened if encoded within emotionally salient contextual information. These findings may assist in understanding mechanisms underlying spontaneous retrieval of emotional associates and the utility of ERPs to study maladaptive involuntary memories in trauma- and stress-related disorders.

Neurophysiological Effects Associated With Subliminal Conditioning of Appetite Motivations

When attempting to encourage eating, explicitly providing statements like "eating is pleasant" may produce little effect. This may be due to subjective, negatively-valenced narratives evoked by perception of the verb "eating" (e.g., eating →fat →lonely), overriding any explicitly provided eating-pleasant valence information. In our study, we presented eating-related verbs under subliminal visual conditions to mitigate the onset of eating-associated deliberation. Verbs were linked with neutral or positively valenced terms across independent blocks. Modulations of event-related magnetoencephalographic (MEG) components and parietal activations in the alpha range (8-12 Hz) illustrated a significant effect of valence during pre-lexical time windows. We found significantly greater saliva production and declarations of increasing hunger after eating-related verbs were linked with positive terms. Orally reported preferences did not vary between conditions.

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.