The proximate regulation of prosocial behaviour: towards a conceptual framework for comparative research.

Humans and many other animal species act in ways that benefit others. Such prosocial behaviour has been studied extensively across a range of disciplines over the last decades, but findings to date have led to conflicting conclusions about prosociality across and even within species. Here, we present a conceptual framework to study the proximate regulation of prosocial behaviour in humans, non-human primates and potentially other animals. We build on psychological definitions of prosociality and spell out three key features that need to be in place for behaviour to count as prosocial: benefitting others, intentionality, and voluntariness. We then apply this framework to review observational and experimental studies on sharing behaviour and targeted helping in human children and non-human primates. We show that behaviours that are usually subsumed under the same terminology (e.g. helping) can differ substantially across and within species and that some of them do not fulfil our criteria for prosociality. Our framework allows for precise mapping of prosocial behaviours when retrospectively evaluating studies and offers guidelines for future comparative work.

Control in context: The theta rhythm provides evidence for reactive control but no evidence for proactive control.

A prime goal of psychological science is to understand how humans can flexibly adapt to rapidly changing contexts. The foundation of this cognitive flexibility rests on contextual adjustments of cognitive control, which can be tested using the list-wide proportion congruency effect (LWPC). Blocks with mostly incongruent (MI) trials show smaller conflict interference effects compared to blocks with mostly congruent (MC) trials. A critical debate is how proactive and reactive control processes drive contextual adjustments. In this preregistered study (N = 30), we address this conundrum, by using the theta rhythm as a key neural marker for cognitive control. In a confound-minimized Stroop paradigm with short alternating MC and MI blocks, we tested reaction times, error rates, and participants' individualized theta activity (2-7 Hz) in the scalp-recorded electroencephalogram. An LWPC effect was found for both, reaction times and error rates. Importantly, the results provided clear evidence for reactive control processes in the theta rhythm: Theta power was higher in rare incongruent compared with congruent trials in MC blocks, but there was no such modulation in MI blocks. However, regarding proactive control, there were no differences in sustained theta power between MC and MI blocks. A complementary analysis of the alpha activity (8-14 Hz) also revealed no evidence for sustained attentional resources in MI blocks. These findings suggest that contextual adjustments rely mainly on reactive control processes in the theta rhythm. Proactive control, in the present study, may be limited to a flexible attentional shift but does not seem to require sustained theta activity.

Visual attention across cultures: Similarities and differences in child development and maternal attention styles.

Previous cross-cultural research has described two different attention styles: a holistic style, characterized by context-sensitive processing, generally associated with interdependent cultural contexts, and an analytic style, a higher focus on salient objects, generally found in independent cultural contexts. Though a general assumption in the field is that attention styles are gradually socialized in culture-specific interactions in childhood, empirical evidence for the proximal mechanisms underlying this development is scarce. This study aimed to document the emergence of cross-cultural differences in attention styles in three cultural contexts differing in social orientations, namely in urban middle-class families from Münster, Germany (i.e., more independent context), and Kyoto, Japan, and Indigenous-heritage families from Cotacachi, Ecuador (i.e., more interdependent contexts). Furthermore, to test the assumption that caregivers' attention guidance is one of the forces driving differential development, we investigated how caregivers guide children's attention. In total, 270 children between 4 and 9 years of age and their mothers participated in three tasks: an eye-tracking task, a picture description task and a forced-choice recognition task. Results indicate a mixed pattern of findings: While some tasks revealed the expected cultural differences, namely a higher object focus in Münster compared to Kyoto and Cotacachi, others did not. Regarding caregivers' attention guidance, we found that mothers in Münster more strongly emphasized the focal object than mothers in Kyoto and Cotacachi. The results are discussed in terms of culture-specific developmental trajectories and the generalizability of attentional processes across tasks and cultural contexts. RESEARCH HIGHLIGHTS: We investigated visual attention styles in 4- to 9-year-old children and their mothers from urban Germany, urban Japan, and rural Ecuador in three different tasks. Special emphasis lied on mothers' verbal attention guidance toward their children as a proximal mechanism underlying the emergence of culture-specific attention styles. Mothers from urban Germany guided their children's attention in more analytic ways than mothers from urban Japan and rural Ecuador. The relevance of verbal attention guidance in the development of culture-specific attention styles has been demonstrated beyond the East-West dichotomy.

Young infants process prediction errors at the theta rhythm.

Examining how young infants respond to unexpected events is key to our understanding of their emerging concepts about the world around them. From a predictive processing perspective, it is intriguing to investigate how the infant brain responds to unexpected events (i.e., prediction errors), because they require infants to refine their predictions about the environment. Here, to better understand prediction error processes in the infant brain, we presented 9-month-olds (N = 36) a variety of physical and social events with unexpected versus expected outcomes, while recording their electroencephalogram (EEG). We found a pronounced response in the ongoing 4-5 Hz theta rhythm for the processing of unexpected (in contrast to expected) events, for a prolonged time window (2 s) and across all scalp-recorded electrodes. The condition difference in the theta rhythm was not related to the condition difference in infants' event-related activity to unexpected (versus expected) events in the negative central (Nc) component (0.4-0.6 s), a component, which is commonly analyzed in infant violation of expectation studies using EEG. These findings constitute critical evidence that the theta rhythm is involved in the processing of prediction errors from very early in human brain development. We discuss how the theta rhythm may support infants' refinement of basic concepts about the physical and social environment.

Motor cortex activity during action observation predicts subsequent action imitation in human infants.

From early on, human infants acquire novel actions through observation and imitation. Yet, the neural mechanisms that underlie infants' action learning are not well understood. Here, we combine the assessment of infants' neural processes during the observation of novel actions on objects (i.e. transitive actions) and their subsequent imitation of those actions. Most importantly, we found that the 7-10 â€‹Hz motor cortex activity increased during action observation and predicted action imitation in 20-month-olds (n â€‹= â€‹36). 10-month-olds (n â€‹= â€‹42), who did not yet reliably imitate others' actions, showed a highly similar neural activity pattern during action observation. The presence or absence of communicative signals did neither affect infants' neural processing nor their subsequent imitation behavior. These findings provide first evidence for neural processes in the motor cortex that allow infants to acquire transitive actions from others ‒ and pinpoint a key learning mechanism in the developing brain of human infants.

Memory entrainment by visually evoked theta-gamma coupling.

The wake human brain constantly encodes novel information and integrates them into existing neuronal representations. It is posited that the formation of new memory traces is orchestrated by the synchronization of neuronal activity in the theta rhythm (3-8 Hz), theta coupled gamma activity (40-120 Hz), and decreases in the alpha rhythm (8-12 Hz). Critically, given the correlative nature of neurophysiological recordings, the functional relevance of oscillatory processes is not well understood. Here, we experimentally enhanced memory formation processes by a rhythmic visual stimulation at an individual theta frequency, in contrast to the stimulation at an individual alpha frequency. This memory entrainment effect was not explained by theta power per se, but was driven by a visually evoked theta-gamma coupling pattern. This underlines the functional role of the theta rhythm and the theta-gamma neuronal code in human episodic memory. The entrainment of mnemonic network mechanisms by a visual stimulation technique provides a proof of concept that visual pacemakers can entrain complex cognitive processes in the wake human brain.

Visually Entrained Theta Oscillations Increase for Unexpected Events in the Infant Brain.

Infants form basic expectations about their physical and social environment, as indicated by their attention toward events that violate their expectations. Yet little is known about the neuronal processing of unexpected events in the infant brain. Here, we used rhythmic visual brain stimulation in 9-month-olds (N = 38) to elicit oscillations of the theta (4 Hz) and the alpha (6 Hz) rhythms while presenting events with unexpected or expected outcomes. We found that visually entrained theta oscillations sharply increased for unexpected outcomes, in contrast to expected outcomes, in the scalp-recorded electroencephalogram. Visually entrained alpha oscillations did not differ between conditions. The processing of unexpected events at the theta rhythm may reflect learning processes such as the refinement of infants' basic representations. Visual brain-stimulation techniques provide new ways to investigate the functional relevance of neuronal oscillatory dynamics in early brain development.

From understanding others' needs to prosocial action: Motor and social abilities promote infants' helping.

In the present study, we test the main hypothesis that infants' understanding of others' needs translates into helping behavior, when critical motor and social competencies have emerged, early in the second year. We assessed the understanding of others' needs in an eye-tracking paradigm and the helping behavior of 10- (n = 41) and 16-month-olds (n = 37). Furthermore, we assessed the motor and social abilities of 16-month-olds. Critically, while infants understood others' needs already at 10 months, fine motor and social interaction skills moderated the link between infants' prosocial understanding and helping behavior at 16 months. This provides first evidence that infants' helping behavior relates to their understanding of others' needs. Furthermore, we found that fine motor, gross motor, and social interaction skills predicted early helping behavior by themselves. These findings highlight that the emergence of infants' helping behavior is the result of a developmental system that includes infants' understanding of others' needs and also their motor and social competencies. The link between infants' understanding of others' needs and their early helpful actions provide further support for the prosocial nature of early helping behavior.

Modeling Prosocial Behavior Increases Helping in 16-Month-Olds.

In two experiments, the imitation of helping behavior in 16-month-olds was investigated. In Study 1 (N = 31), infants either observed an adult model helping or not helping another individual before they had the opportunity to assist an unfamiliar experimenter. In one of two tasks, more children helped in the prosocial model condition than in the no model control condition. In Study 2 (N = 60), a second control condition was included to test whether infants imitated the prosocial intention (no neediness control). Children in the prosocial model condition helped more readily than children in the no model condition, with the second control condition falling in between. These findings propose that modeling provides a critical learning mechanism in early prosocial development.

Coherence in general and personal semantic knowledge: functional differences of the posterior and centro-parietal N400 ERP component.

A growing body of scientific literature investigated the difference between general and personal semantic knowledge. In contrast to general world knowledge, personal semantics comprises highly individual knowledge about oneself. The present study aimed to differentiate processes of integration into personal as opposed to general semantic knowledge. For that purpose, participants were presented with pictures of themselves (Self-condition) or unknown persons (Other-condition) superimposed on a congruent or incongruent background. We hypothesized that self-referential processing is based on automatic retrieval of personal information as opposed to the processing of unknown persons, which requires voluntary, i.e., strategic, attention demanding processing. The topography of the N400 effect varied as a function of the type of semantic knowledge. We found a centro-parietal N400 effect within the Self-condition and a posterior effect within the Other-condition. The voluntary integration of facial expressions of unknown persons within the Other-condition was, furthermore, indexed by an N170 effect. The unresolved tension in personal semantics was reflected by the N500. Our study thus provides new impulses for interpretation of the N400's functional properties and extends our knowledge about the N500. Implications for the functional properties of the self as an organizational structure are discussed.

Neuronal Oscillations Indicate Sleep-dependent Changes in the Cortical Memory Trace.

Sleep promotes the consolidation of newly acquired associative memories. Here we used neuronal oscillations in the human EEG to investigate sleep-dependent changes in the cortical memory trace. The retrieval activity for object-color associations was assessed immediately after encoding and after 3 hr of sleep or wakefulness. Sleep had beneficial effects on memory performance and led to reduced event-related theta and gamma power during the retrieval of associative memories. Furthermore, event-related alpha suppression was attenuated in the wake group for memorized and novel stimuli. There were no sleep-dependent changes in retrieval activity for missed items or items retrieved without color. Thus, the sleep-dependent reduction in theta and gamma oscillations was specific for the retrieval of associative memories. In line with theoretical accounts on sleep-dependent memory consolidation, decreased theta may indicate reduced mediotemporal activity because of a transfer of information into neocortical networks during sleep, whereas reduced parietal gamma may reflect effects of synaptic downscaling. Changes in alpha suppression in the wake group possibly index reduced attentional resources that may also contribute to a lower memory performance in this group. These findings indicate that the consolidation of associative memories during sleep is associated with profound changes in the cortical memory trace and relies on multiple neuronal processes working in concert.

Visual cortical networks align with behavioral measures of context-sensitivity in early childhood.

This study investigates how visual cortical networks align with context-sensitivity, namely the relative focus on the object versus the background of a visual scene, in early childhood. Context-sensitivity was assessed by a picture description and a recognition memory task. To segregate object and background processing in the visual cortex in 5- and 7-year-old children, object and background were presented at different frequencies (12 Hz or 15 Hz), evoking disparate neuronal responses (steady state visually evoked potentials, SSVEPs) in the electroencephalogram. In younger compared to older children the background elicited higher SSVEPs. Visual cortical processing of object versus background was associated with behavioral measures for older but not for younger children. This relation was strongest for verbal descriptions and generalized to the cortical processing of abstract stimuli and object and background presented alone. Thus, visual cortical networks restructure and align with behavioral measures of context-sensitivity in early childhood.

Infants Understand Others' Needs.

Infants begin to help other individuals in the second year of life. However, it is still unclear whether early helping behavior is based on an understanding of other individuals' needs and is thus motivated prosocially. In the present eye-tracking study, 9- to 18-month-old infants (N= 71) saw a character in need of help, unable to reach its goal because of an obstacle, and a second character that was able to achieve a goal on its own. When a third individual (a helper) initiated an action, the infants expected the helper to help the character in need (as indicated during the anticipatory-looking and violation-of-expectation phases). Their prosocial understanding did not differ between age groups and was not related to their helping behavior (measured in two behavioral tasks). Thus, infants understand other individuals' needs even before they start to help others themselves. This indicates that early helping may indeed be motivated prosocially and raises the question of which other competences underlie the ontogeny of helping behavior.

Cultural Influences on Toddlers' Prosocial Behavior: How Maternal Task Assignment Relates to Helping Others.

This cross-cultural study investigates how maternal task assignment relates to toddlers' requested behavior and helping between 18 and 30 months. One hundred seven mother-child dyads were assessed in three different cultural contexts (rural Brazil, urban Germany, and urban Brazil). Brazilian mothers showed assertive scaffolding (serious and insistent requesting), whereas German mothers employed deliberate scaffolding (asking, pleading, and giving explanations). Assertive scaffolding related to toddlers' requested behavior in all samples. Importantly, assertive scaffolding was associated with toddlers' helping in rural Brazil, whereas mothers' deliberate scaffolding related to toddlers' helping behavior in urban Germany. These findings highlight the role of caregivers' socialization practices for the early ontogeny of helping behavior and suggest culture-specific developmental pathways along the lines of interpersonal responsibility and personal choice.

The theta-gamma code in predictive processing and mnemonic updating.

Predictive processing has become a leading theory about how the brain works. Yet, it remains an open question how predictive processes are realized in the brain. Here I discuss theta-gamma coupling as one potential neural mechanism for prediction and model updating. Building on Lisman and colleagues SOCRATIC model, theta-gamma coupling has been associated with phase precession and learning phenomena in medio-temporal lobe of rodents, where it completes and retains a sequence of places or items (i.e., predictive models). These sequences may be updated upon prediction errors (i.e., model updating), signaled by dopaminergic inputs from prefrontal networks. This framework, spanning the molecular to the network level, matches excitingly well with recent findings on predictive processing, mnemonic updating, and perceptual foraging for the theta-gamma code in human cognition. In sum, I use the case of theta-gamma coupling to link the predictive processing account, a very general concept of how the brain works, to specific neural processes which may implement predictive processing and model updating at the cognitive, network, cellular and molecular level.

Early social-cognitive development as a dynamic developmental system-a lifeworld approach.

Based on developmental systems and dynamic systems theories, we propose the lifeworld approach-a conceptual framework for research and a hypothesis concerning early social-cognitive development. As a framework, the lifeworld approach recognizes the social embeddedness of development and shifts the focus away from individual developmental outcomes toward the reciprocal interplay of processes within and between individuals that co-constitutes early social-cognitive development. As a hypothesis, the lifeworld approach proposes that the changing developmental system-spanning the different individuals as their subsystems-strives toward attractor states through regulation at the behavioral level, which results in both the emergence and further differentiation of developmental attainments. The lifeworld approach-as a framework and a hypothesis, including key methodological approaches to test it-is exemplified by research on infants' self-awareness, prosocial behavior and social learning. Equipped with, first, a conceptual framework grounded in a modern view on development and, second, a growing suite of methodological approaches, developmental science can advance by analyzing the mutually influential relations between intra-individual and interactional processes in order to identify key mechanisms underlying early social-cognitive development.

Preverbal infants' understanding of social norms.

Social norms are foundational to human cooperation and co-existence in social groups. A crucial marker of social norms is that a behavior is not only shared, but that the conformity to the behavior of others is a basis for social evaluation (i.e., reinforcement and sanctioning), taking the is, how individuals usually behave, to an ought, how individuals should behave to be socially approved by others. In this preregistered study, we show that 11-month-old infants grasp this fundamental aspect about social norms already in their first year. They showed a pupillary surprise response for unexpected social responses, namely the disapproval and exclusion of an individual who showed the same behavior like others or the approval and inclusion of an individual who behaved differently. That preverbal infants link the conformity with others' behavior to social evaluations, before they respond to norm violations themselves, indicates that the foundations of social norm understanding lie in early infancy.

Communicative signals during joint attention promote neural processes of infants and caregivers.

Communicative signals such as eye contact increase infants' brain activation to visual stimuli and promote joint attention. Our study assessed whether communicative signals during joint attention enhance infant-caregiver dyads' neural responses to objects, and their neural synchrony. To track mutual attention processes, we applied rhythmic visual stimulation (RVS), presenting images of objects to 12-month-old infants and their mothers (n = 37 dyads), while we recorded dyads' brain activity (i.e., steady-state visual evoked potentials, SSVEPs) with electroencephalography (EEG) hyperscanning. Within dyads, mothers either communicatively showed the images to their infant or watched the images without communicative engagement. Communicative cues increased infants' and mothers' SSVEPs at central-occipital-parietal, and central electrode sites, respectively. Infants showed significantly more gaze behaviour to images during communicative engagement. Dyadic neural synchrony (SSVEP amplitude envelope correlations, AECs) was not modulated by communicative cues. Taken together, maternal communicative cues in joint attention increase infants' neural responses to objects, and shape mothers' own attention processes. We show that communicative cues enhance cortical visual processing, thus play an essential role in social learning. Future studies need to elucidate the effect of communicative cues on neural synchrony during joint attention. Finally, our study introduces RVS to study infant-caregiver neural dynamics in social contexts.

Mealtime conversations between parents and their 2-year-old children in five cultural contexts.

Children all over the world learn language, yet the contexts in which they do so vary substantially. This variation needs to be systematically quantified to build robust and generalizable theories of language acquisition. We compared communicative interactions between parents and their 2-year-old children (N = 99 families) during mealtime across five cultural settings (Brazil, Ecuador, Argentina, Germany, and Japan) and coded the amount of talk and gestures as well as their conversational embedding (interlocutors, function, and themes). We found a comparable pattern of communicative interactions across cultural settings, which were modified in ways that are consistent with local norms and values. These results suggest that children encounter similarly structured communicative environments across diverse cultural contexts and will inform theories of language learning. (PsycInfo Database Record (c) 2024 APA, all rights reserved).