Biology subjects

Schacht, A.

Publications and source records attributed to Schacht, A..

14 recordsLinked to original sources

bioRxiv2026

Pupil Dynamics reflect Compensatory Control during Continuous Motor-Control following Cognitive Demand

Pupillometry is commonly used to assess workload and fatigue, but its interpretation in applied, continuous-control tasks remains unclear because pupil responses are strongly shaped by task context and often lack a theory-guided interpretive basis. The Compensatory Control Model and Locus Coeruleus-Norepinephrine system offer complementary frameworks for interpreting pupil dynamics in relation to regulatory effort and engagement under sustained cognitive demand. We aimed to examine how tonic and phasic pupil dynamics reflect compensatory regulation following sustained cognitive demand, and how these dynamics relate to subsequent performance during continuous motor control. Participants completed two sessions consisting of a low- versus high- demand working-memory task followed by a joystick-based continuous motor-control task. Linear mixed-effects models tested demand effects on pupil dynamics and behavior and evaluated trial- level pupil-performance associations. Prior high demand produced small and specific changes in motor-control performance. Task-evoked pupil response showed effects of engagement dependent on prior demand and small associations with movement timing and accuracy. Our results show that pupil dynamics sensitively reflect sustained cognitive demand, but their trial-level predictive value for subsequent continuous motor performance is limited.

neuroscience↗

bioRxiv2025

Distinct neural routes for evaluative and informational social influence

Humans routinely revise their judgments based on input from others, yet how the brain mechanisms distinguish evaluative from informational social influence remains unclear. Using preregistered electroencephalography (EEG, N = 87) and the Judge-Advisor System, we identified distinct neurocognitive routes by which feedback and advice shape judgment revision. Participants made numerical estimates, received either feedback ("good"/"bad") or advice (alternative estimates) of varying proximity to their own judgment, and then revised their response. Feedback engaged rapid evaluative monitoring: a feedback-related negativity (FRN, 200-300ms) that decreased with confidence, indicating reflexive performance assessment. Advice triggered delayed deliberate processing: late positive complex (LPC) onset latencies that slowed when confident individuals encountered discrepant advice, indicating effortful integration of external information. Both routes converged on the P300 (250-250ms),whose amplitudes increased with proximity, consistent with the reward value of social validation. These findings reveal a dual-route architecture: feedback determines whether to revise through rapid evaluative signals, while advice specifies how much to revise through sustained integrative processes. Confidence calibrates both routes, protecting against misleading feedback while intensifying deliberation over discrepant advice. This temporal dissociation clarifies how metacognitive and social processes coordinate adaptive judgment revision.

neuroscience↗

bioRxiv2025

Social learning of emotion and its implication for memory: An ERP Study

Social learning of emotional salience from surrounding social cues is especially advantageous under conditions of uncertainty. Yet, the neural mechanisms underlying this process and its consolidation into long-term memory remain poorly understood. In this two-day EEG study, we examined whether emotional salience from social cues (facial expressions) transfers to perceptually uncertain target images, and whether such learned salience is preserved in memory even after the social cues are removed. On Day 1 (learning session), we found no evidence for automatic emotional salience transfer across trials. Instead, ERP results indicated that social cue use was modulated by participants metacognitive state of subjective uncertainty, as reflected in the P1 amplitudes. On Day 2 (test session), recognition memory revealed evidence of additive emotional salience: EPN amplitudes were enhanced for accurately classified positive target images previously paired with social cues. In contrast, LPC amplitudes were reduced for negative target images in the social condition, regardless of classification accuracy. Together, these findings suggest that the influence of social cues is contingent on subjective uncertainty. Social cues enhanced emotional salience when internal valence judgments were strong (as for positive images), but led to increased reliance on the cue--and therefore dampened memory encoding--when internal valence judgments were weaker (as for negative images).

neuroscience↗

bioRxiv2025

The Moral Brain in Context: Political Orientation, Empathy, and Evaluation of Everyday Behavior

Moral judgments are central to guiding social interactions, influencing whom we trust, cooperate with, or avoid. While extensive research has examined the cognitive and affective bases of moral evaluation, less is known about how stable traits - such as political orientation and empathy - shape these judgments and their neural correlates in ecologically valid contexts. Across two studies, we investigated how people evaluate individuals who committed harmful, helpful, or neutral actions. In Study 1 (N = 214), participants read everyday moral scenarios paired with neutral faces. Empathy moderated gender effects in judging harmful acts, and political orientation selectively influenced ratings of morally ambiguous (neutral) actions. In Study 2 (N = 39), pre-screened conservatives and progressives (N = 675 prescreen) viewed the same agents in an EEG paradigm. Likeability ratings varied by moral valence but not political orientation. Event-related potential analyses revealed that conservatives showed consistently elevated Late Positive Potentials (LPPs) across all conditions, whereas progressives displayed selective LPP enhancement for helpful individuals, suggesting group differences in motivational salience attribution. Together, these findings show that political orientation and empathy influence both explicit moral evaluations and neural processing of socially relevant information. Such insights deepen our understanding of how enduring traits shape moral judgments.

neuroscience↗

bioRxiv2025

Mapping social relevance in affective scenes: A large-scale multidimensional rating study

Understanding how individuals evaluate social content in affective scenes is crucial for research in emotion, social cognition, and decision-making. However, standardized image databases often lack fine-grained ratings of social dimensions beyond basic emotional content. We present a normative dataset of 296 affective scenes rated by 424 adult participants across six social-affective dimensions: social relevance, emotion sharing, action sharing, interpersonal equality, scene pleasantness, and participatory arousal. Each image was independently coded for objective features such as number of people, face visibility, and gaze direction. All rating dimensions showed excellent interrater reliability. Pleasantness ratings demonstrated strong convergent validity with established valence norms from the International Affective Picture System (IAPS), while arousal ratings differentiated between experienced and participatory arousal, suggesting that the latter captures a distinct affective component. Correlation analyses revealed that social relevance was strongly predicted by scene pleasantness and a composite "engagement" factor combining emotion sharing, action sharing, and equality. Notably, the association between pleasantness and social relevance was especially pronounced in scenes depicting single individuals. Linear mixed models further indicated that extraversion modestly amplified the relationship between engagement and social relevance, while other personality traits and empathy did not significantly affect ratings. This open-access dataset provides a reliable, multidimensional tool for selecting affective scenes based on both emotional and social-interpersonal features. It supports improved stimulus control and design in a wide range of behavioral and neurocognitive research. By systematically mapping social meaning in static affective scenes, our study advances existing methodological resources and offers empirical insight into the structure of social-affective appraisals. All image codes, mean ratings, and analysis scripts are publicly available via the Open Science Framework.

neuroscience↗

bioRxiv2025

Continuous dynamics of cooperation and competition in social foraging

Real-life social interactions often unfold continuously and involve dynamic cooperation and competition, yet most studies rely on discrete games that do not capture the adaptive and graded nature of continuous sensorimotor decisions. To address this gap, we developed the Cooperation-Competition Foraging game -- an ecologically grounded paradigm in which pairs of participants (dyads) navigate a continuous shared space under face-to-face visibility, deciding in real-time to collect rewarded targets either individually or jointly. Dyads (n=58, 116 participants) spontaneously converged on distinct stable strategies along the cooperation-competition spectrum, forming three groups: cooperative, intermediate, and competitive. Despite the behavioral complexity, our computational model, which incorporated travel path minimization, sensorimotor communication, and recent choice history, predicted dyadic decisions with 87% accuracy, and linked prediction certainty with ensuing dynamics of spatiotemporal coordination. Further modeling revealed how sensorimotor factors, such as movement speed and skill, shape distinct strategies and payoffs. Crucially, we quantify the cost of cooperation, demonstrating that in many dyads prosocial tendencies outweigh the individual benefits of exploiting skill advantages. Our versatile framework provides a predictive, mechanistic account of how social and embodied drivers promote the emergence of dynamic cooperation and competition, and offers rigorous metrics for investigating the neural basis of naturalistic social interactions, and for linking personality traits to distinct strategies.

neuroscience↗

bioRxiv2021

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

Stimuli associated with high reward modulate perception and such value-driven effects have been shown to originate from the modulation of the earliest stages of sensory processing in the brain. In natural environments objects comprise multiple features (imagine a rolling soccer ball, with its black and white patches and the swishing sound made during its motion), where each feature may signal different associations with previously encountered rewards. How perception of such an object is affected by the value associations of its constituent parts is unknown. The present study compares intra- and cross-modal value-driven effects on behavioral and electrophysiological correlates of visual perception. Human participants first learned the reward associations of visual and auditory cues. Subsequently, they performed a visual orientation discrimination task in the presence of previously rewarded visual or auditory cues (intra- and cross-modal cues, respectively) that were concurrently presented with the target stimulus. During the conditioning phase, when reward associations were learned and reward cues were the target of the task, reward value of both modalities enhanced the electrophysiological correlates of sensory processing in visual cortex. During the post-conditioning phase, when reward delivery was halted and previously rewarded stimuli were task-irrelevant, cross-modal value-enhanced behavioral measures of visual sensitivity whereas intra-modal value led to a trend for suppression. A similar pattern of modulations was found in the simultaneously recorded event-related potentials (ERPs) of posterior electrodes. We found an early (90-120 ms) suppression of ERPs evoked by high-value, intra-modal stimuli. Cross-modal cues 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 of the posterior electrodes. These results indicate that visual cortex is modulated by the reward value of visual as well as auditory cues. Previously rewarded, task-irrelevant cues from the same or different sensory modality have a different effect on visual perception, as intra-modal high-value cues may interfere with the target processing, whereas cross-modal high-value cues boost the perception of the target.

neuroscience↗

bioRxiv2019

Hormonal and modality specific effects on males’ emotion recognition ability

Successful emotion recognition is a key component of our socio-emotional communication skills. However, little is known about the factors impacting males accuracy in emotion recognition tasks. This pre-registered study examined potential candidates, focusing on the modality of stimulus presentation, emotion category, and individual hormone levels. We obtained accuracy and reaction time scores from 312 males who categorized voice, face and voice-face stimuli for nonverbal emotional content. Results showed that recognition accuracy was significantly higher in the audio-visual than in the auditory or visual modality. While no significant association was found for testosterone and cortisol alone, the effect of the interaction with recognition accuracy and reaction time was significant, but small. Our results establish that audio-visual congruent stimuli enhance recognition accuracy and provide novel empirical support by showing that the interaction of testosterone and cortisol modulate to some extent males accuracy and response times in emotion recognition tasks.

physiology↗

bioRxiv2019

The Role of Emotions in Moral Judgments: Time-resolved evidence from event-related brain potentials

The influence of emotion on moral judgments has become increasingly prominent in recent years. While explicit normative measures are widely used to investigate this relationship, event-related potentials (ERPs) offer the advantage of a preconscious method to visualize the modulation of moral judgments. Based on Gray and Wegners (2009) Dimensional Moral Model, the present study investigated whether the processing of neutral faces is modulated by moral context information. We hypothesized that neutral faces gain emotional valence when presented in a moral context and thus elicit ERP responses comparable to those established for the processing of emotional faces. Participants (N= 26, 13 female) were tested with regard to their implicit (ERPs) and explicit (morality rating) responses to neutral faces, shown in either a morally positive, negative, or neutral context. Higher ERP amplitudes in early (P100, N170) and later (EPN, LPC) processing stages were expected for harmful/helpful scenarios compared to neutral scenarios. Agents and patients were expected to differ for moral compared to neutral scenarios. In the explicit ratings neutral scenarios were expected to differ from moral scenarios. In ERPs, we found indications for an early modulation of moral valence (harmful/helpful) and an interaction of agency and moral valence after 80-120 ms. Later time sequences showed no significant differences. Morally positive and negative scenarios were rated as significantly different from neutral scenarios. Overall, the results indicate that the relationship of emotion and moral judgments can be observed on a preconscious neural level at an early processing stage as well as in explicit judgments.

neuroscience↗

bioRxiv2018

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

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

neuroscience↗

bioRxiv2017

Differential effects of learned associations with words and pseudowords on event-related brain potentials

Associated stimulus valence affects neural responses at an early processing stage. However, in the field of written language processing, it is unclear whether semantics of a word or low-level visual features affect early neural processing advantages. The current study aimed to investigate the role of semantic content on reward and loss associations. Participants completed a learning session to associate either words (Experiment 1, N=24) or pseudowords (Experiment 2, N=24) with different monetary outcomes (gain-associated, neutral or loss-associated). Gain-associated stimuli were learned fastest. Behavioural and neural response changes based on the associated outcome were further investigated in separate test sessions. Responses were faster towards gain- and loss-associated than neutral stimuli if they were words, but not pseudowords. Early P1 effects of associated outcome occurred for both pseudowords and words. Specifically, loss-association resulted in increased P1 amplitudes to pseudowords, compared to decreased amplitudes to words. Although visual features are likely to explain P1 effects for pseudowords, the inversed effect for words suggests that semantic content affects associative learning, potentially leading to stronger associations.\n\nHighlights- Neural mechanisms of gain/loss association to pseudowords and words were investigated\n- Loss effects can be observed for the P1 component\n- Words and pseudowords differ in the direction of loss effects\n- Semantic content may play a role during word association\n- Low-level visual features may play a role during pseudoword association

neuroscience↗

bioRxiv2017

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

Emotion effects in event-related potentials (ERPs) during reading have been observed at very short latencies of around 100 to 200 ms after word onset. The nature of these effects remains a matter of debate: First, it is possible that they reflect semantic access, which might thus occur much faster than proposed by most reading models. Second, it is possible that associative learning of a words shape might contribute to the emergence of emotion effects during visual processing. The present study addressed this question by employing an associative learning paradigm on pronounceable letter strings (pseudowords). In a learning session, letter strings were associated with positive, neutral or negative valence by means of monetary gain, loss or zero-outcome. Crucially, half of the stimuli were learned in the visual modality, while the other half was presented acoustically, allowing for experimental separation of associated valence and physical percept. In a test session one or two days later, acquired letter string were presented in an old/new decision task while we recorded event-related potentials. Behavioural data showed an advantage for gain-associated stimuli both during learning and in the delayed old/new task. Early emotion effects in ERPs were limited to visually acquired letter strings, but absent for acoustically acquired letter strings. These results imply that associative learning of a words visual features might play an important role in the emergence of emotion effects at the stage of perceptual processing.

neuroscience↗

bioRxiv2017

Implicit reward associations impact face processing: Time-resolved evidence from event-related brain potentials and pupil dilations

The present study aimed at investigating whether associated motivational salience causes preferential processing of inherently neutral faces similar to emotional expressions by means of event-related brain potentials (ERPs) and changes of the pupil size. To this aim, neutral faces were implicitly associated with monetary outcome, while participants (N = 44) performed a subliminal face-matching task that ensured performance around chance level and thus an equal proportion of gain, loss, and zero outcomes. Motivational context strongly impacted processing of all - even task-irrelevant - stimuli prior to the target face, indicated by enhanced amplitudes of subsequent ERP components and increased pupil size. In a separate test session, previously associated faces as well as novel faces with emotional expressions were presented within the same task but without motivational context and performance feedback. Most importantly, previously gain-associated faces amplified the LPC, although the individually contingent face-outcome assignments were not made explicit during the learning session. Emotional expressions impacted the N170 and EPN components. Modulations of the pupil size were absent in both motivationally-associated and emotional conditions. Our findings demonstrate that neural representations of neutral stimuli can acquire increased salience via implicit learning, with an advantage for gain over loss associations.

neuroscience↗

bioRxiv2017

Spatio-Temporal Pattern of Appraising Social and Emotional Relevance: Evidence from Event-Related Brain Potentials

Social information is highly intrinsically relevant for the human species because of its direct link to guiding physiological responses and behavior. Accordingly, extant functional magnetic resonance imaging (fMRI) data suggest that social content may form a unique stimulus dimension. It remains largely unknown, however, how neural activity underlying social (versus nonsocial) information processing temporally unfolds, and how such social information appraisal may interact with the processing of other stimulus characteristics, particularly emotional meaning. Here, we presented complex visual scenes differing in both social (versus nonsocial) and emotional relevance (positive, negative, neutral) intermixed with scrambled versions of these pictures to N= 24 healthy young adults. Event-related brain potentials (ERPs) to intact pictures were examined for gaining insight to the dynamics of appraisal of both dimensions, implemented within the brain. Our main finding is an early interaction between social and emotional relevance due to enhanced amplitudes of early ERP components to emotionally positive pictures of social compared to nonsocial content, presumably reflecting rapid allocation of attention and counteracting an overall negativity bias. Importantly, our ERP data show high similarity with previously observed fMRI data using the same stimuli, and source estimations located the ERP effects in overlapping occipito-temporal brain areas. Our new data suggest that relevance detection may occur already as early as around 100 ms after stimulus onset and may combine relevance checks not only examining intrinsic pleasantness/emotional valence, but also social content as a unique, highly relevant stimulus dimension.

neuroscience↗