Validation of an open source, remote web-based eye-tracking method (WebGazer) for research in early childhood

Measuring eye movements remotely via the participant's webcam promises to be an attractive methodological addition to in-person eye-tracking in the lab. However, there is a lack of systematic research comparing remote web-based eye-tracking with in-lab eye-tracking in young children. We report a multi-lab study that compared these two measures in an anticipatory looking task with toddlers using WebGazer.js and jsPsych. Results of our remotely tested sample of 18-27-month-old toddlers (N = 125) revealed that web-based eye-tracking successfully captured goal-based action predictions, although the proportion of the goal-directed anticipatory looking was lower compared to the in-lab sample (N = 70). As expected, attrition rate was substantially higher in the web-based (42%) than the in-lab sample (10%). Excluding trials based on visual inspection of the match of time-locked gaze coordinates and the participant's webcam video overlayed on the stimuli was an important preprocessing step to reduce noise in the data. We discuss the use of this remote web-based method in comparison with other current methodological innovations. Our study demonstrates that remote web-based eye-tracking can be a useful tool for testing toddlers, facilitating recruitment of larger and more diverse samples; a caveat to consider is the larger drop-out rate.

Toddlers' affective responses to sociomoral scenes: Insights from physiological measures

A growing literature suggests that preverbal infants are sensitive to sociomoral scenes and prefer prosocial agents over antisocial agents. It remains unclear, however, whether and how emotional processes are implicated in infants' responses to prosocial/antisocial actions. Although a recent study found that infants and toddlers showed more positive facial expressions after viewing helping (vs. hindering) events, these findings were based on naïve coder ratings of facial activity; furthermore, effect sizes were small. The current studies examined 18- and 24-month-old toddlers' real-time reactivity to helping and hindering interactions using three physiological measures of emotion-related processes. At 18 months, activity in facial musculature involved in smiling/frowning was explored via facial electromyography (EMG). At 24 months, stress (sweat) was explored via electrodermal activity (EDA). At both ages, arousal was explored via pupillometry. Behaviorally, infants showed no preferences for the helper over the hinderer across age groups. EMG analyses revealed that 18-month-olds showed higher corrugator activity (more frowning) during hindering (vs. helping) actions, followed by lower corrugator activity (less frowning) after hindering (vs. helping) actions finished. These findings suggest that antisocial actions elicited negativity, perhaps followed by brief disengagement. EDA analyses revealed no significant event-related differences. Pupillometry analyses revealed that both 18- and 24-month-olds' pupils were smaller after viewing hindering (vs. helping), replicating recent evidence with 5-month-olds and suggesting that toddlers also show less arousal following hindering than following helping. Together, these results provide new evidence with respect to whether and how arousal/affective processes are involved when infants process sociomoral scenarios.

How to build up big team science: a practical guide for large-scale collaborations

The past decade has witnessed a proliferation of big team science (BTS), endeavours where a comparatively large number of researchers pool their intellectual and/or material resources in pursuit of a common goal. Despite this burgeoning interest, there exists little guidance on how to create, manage and participate in these collaborations. In this paper, we integrate insights from a multi-disciplinary set of BTS initiatives to provide a how-to guide for BTS. We first discuss initial considerations for launching a BTS project, such as building the team, identifying leadership, governance, tools and open science approaches. We then turn to issues related to running and completing a BTS project, such as study design, ethical approvals and issues related to data collection, management and analysis. Finally, we address topics that present special challenges for BTS, including authorship decisions, collaborative writing and team decision-making.

We aren't especially fearful apes, and fearful apes aren't especially prosocial

Grossmann posits that heightened fearfulness in humans evolved to facilitate cooperative caregiving. We argue that three of his claims - that children express more fear than other apes, that they are uniquely responsive to fearful expressions, and that expression and perception of fear are linked with prosocial behaviors - are inconsistent with existing literature or require additional supporting evidence.

Are Real-World Prosociality Programs Associated with Greater Psychological Well-Being in Primary School-Aged Children?

Quality education can build a sustainable, happier world, but what experiences support student well-being? Numerous laboratory studies suggest that prosocial behavior predicts greater psychological well-being. However, relatively little work has examined whether real-world prosociality programs are associated with greater well-being in primary school-aged children (aged 5-12). In Study 1, we surveyed 24/25 students who completed their 6th Grade curriculum in a long-term care home alongside residents called "Elders," which offered numerous opportunities for planned and spontaneous helping. We found that the meaning that students derived from their prosocial interactions with the Elders was strongly associated with greater psychological well-being. In Study 2, we conducted a pre-registered field experiment with 238 primary school-aged children randomly assigned to package essential items for children who experience homelessness and/or poverty who were either demographically similar or dissimilar in age and/or gender to them as part of a classroom outing. Children self-reported their happiness both pre- and post-intervention. While happiness increased from pre- to post-intervention, this change did not differ for children who helped a similar or dissimilar recipient. These studies offer real-world evidence consistent with the possibility that engaging in prosocial classroom activities-over an afternoon or year-is associated with greater psychological well-being in primary school-aged children.

A Cooperation Advantage for Theory of Mind in Children and Adults

Three studies test whether people engage in mental state reasoning or theory of mind (ToM) differently across two fundamental social contexts: cooperation and competition. Study 1 examines how children with an emerging understanding of false beliefs deploy ToM across these contexts. We find that young preschool children are better able to plant false beliefs in others' minds in a cooperative versus competitive context; this difference does not emerge for other cognitive capacities tested (e.g., executive functioning, memory). Studies 2a and 2b reveal the same systematic difference in adults' ToM for cooperation and competition, even after accounting for relevant predictors (e.g., preference for a task condition, feelings about deception). Together, these findings provide initial evidence for enhanced ToM for cooperation versus competition in early development and also adulthood.

A multi-lab study of bilingual infants: Exploring the preference for infant-directed speech

From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants' IDS preference. As part of the multi-lab ManyBabies 1 project, we compared lab-matched samples of 333 bilingual and 385 monolingual infants' preference for North-American English IDS (cf. ManyBabies Consortium, 2020: ManyBabies 1), tested in 17 labs in 7 countries. Those infants were tested in two age groups: 6-9 months (the younger sample) and 12-15 months (the older sample). We found that bilingual and monolingual infants both preferred IDS to ADS, and did not differ in terms of the overall magnitude of this preference. However, amongst bilingual infants who were acquiring North-American English (NAE) as a native language, greater exposure to NAE was associated with a stronger IDS preference, extending the previous finding from ManyBabies 1 that monolinguals learning NAE as a native language showed a stronger preference than infants unexposed to NAE. Together, our findings indicate that IDS preference likely makes a similar contribution to monolingual and bilingual development, and that infants are exquisitely sensitive to the nature and frequency of different types of language input in their early environments.

Building a collaborative Psychological Science: Lessons learned from ManyBabies 1

The field of infancy research faces a difficult challenge: some questions require samples that are simply too large for any one lab to recruit and test. ManyBabies aims to address this problem by forming large-scale collaborations on key theoretical questions in developmental science, while promoting the uptake of Open Science practices. Here, we look back on the first project completed under the ManyBabies umbrella - ManyBabies 1 - which tested the development of infant-directed speech preference. Our goal is to share the lessons learned over the course of the project and to articulate our vision for the role of large-scale collaborations in the field. First, we consider the decisions made in scaling up experimental research for a collaboration involving 100+ researchers and 70+ labs. Next, we discuss successes and challenges over the course of the project, including: protocol design and implementation, data analysis, organizational structures and collaborative workflows, securing funding, and encouraging broad participation in the project. Finally, we discuss the benefits we see both in ongoing ManyBabies projects and in future large-scale collaborations in general, with a particular eye towards developing best practices and increasing growth and diversity in infancy research and psychological science in general. Throughout the paper, we include first-hand narrative experiences, in order to illustrate the perspectives of researchers playing different roles within the project. While this project focused on the unique challenges of infant research, many of the insights we gained can be applied to large-scale collaborations across the broader field of psychology.

The Homogeneity and Heterogeneity of Moral Functioning in Preschool

The current study examined relations between distinct aspects of moral functioning, and their cognitive and emotional correlates, in preschool age children. Participants were 171 typically developing 3- to 6-year-olds. Each child completed several tasks, including (a) moral tasks assessing both performance of various moral actions and evaluations of moral scenarios presented both verbally and nonverbally; and (b) non-moral tasks assessing general cognitive skill, executive functioning, theory-of-mind, and emotion recognition. Shyness and empathic concern were assessed from video acquired during participation. Results demonstrated positive associations among distinct moral actions, as well as among distinct moral evaluation tasks, but few associations between tasks assessing moral actions and moral evaluation. Empathic concern and inhibitory control each emerged as important predictors of preschoolers' moral functioning.

Quantifying Sources of Variability in Infancy Research Using the Infant-Directed-Speech Preference

Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure.

Do Dogs Prefer Helpers in an Infant-Based Social Evaluation Task?

Social evaluative abilities emerge in human infancy, highlighting their importance in shaping our species' early understanding of the social world. Remarkably, infants show social evaluation in relatively abstract contexts: for instance, preferring a wooden shape that helps another shape in a puppet show over a shape that hinders another character (Hamlin et al., 2007). Here we ask whether these abstract social evaluative abilities are shared with other species. Domestic dogs provide an ideal animal species in which to address this question because this species cooperates extensively with conspecifics and humans and may thus benefit from a more general ability to socially evaluate prospective partners. We tested dogs on a social evaluation puppet show task originally used with human infants. Subjects watched a helpful shape aid an agent in achieving its goal and a hinderer shape prevent an agent from achieving its goal. We examined (1) whether dogs showed a preference for the helpful or hinderer shape, (2) whether dogs exhibited longer exploration of the helpful or hinderer shape, and (3) whether dogs were more likely to engage with their handlers during the helper or hinderer events. In contrast to human infants, dogs showed no preference for either the helper or the hinderer, nor were they more likely to engage with their handlers during helper or hinderer events. Dogs did spend more time exploring the hindering shape, perhaps indicating that they were puzzled by the agent's unhelpful behavior. However, this preference was moderated by a preference for one of the two shapes, regardless of role. These findings suggest that, relative to infants, dogs show weak or absent social evaluative abilities when presented with abstract events and point to constraints on dogs' abilities to evaluate others' behavior.

Children’s Judgments of Epistemic and Moral Agents: From Situations to Intentions

Children’s evaluations of moral and epistemic agents crucially depend on their discerning that an agent’s actions were performed intentionally. Here we argue that children’s epistemic and moral judgments reveal practices of forgiveness and blame, trust and mistrust, and objection or disapproval and that such practices are supported by children’s monitoring of the situational constraints on agents. Inherent in such practices is the understanding that agents are responsible for actions performed under certain conditions but not others. We discuss a range of situational constraints on children’s early epistemic and moral evaluations and clarify how these situational constraints serve to support children’s identification of intentional actions. By monitoring the situation, children distinguish intentional from less intentional action and selectively hold epistemic and moral agents accountable. We argue that these findings inform psychological and philosophical theorizing about attributions of moral and epistemic agency and responsibility.

Preschoolers Focus on Others' Intentions When Forming Sociomoral Judgments

Many studies suggest that preschoolers initially privilege outcome over intention in their moral judgments. The present findings reveal that, in contrast, even younger preschoolers can privilege intentions when evaluating characters who successfully or unsuccessfully help or hinder a third party in achieving its goal. Following a live-action puppet show originally created for infant populations, children made a forced-choice social judgment (which puppet was liked) and two forced-choice moral judgments (which puppet was nicer, which puppet should be punished), and were asked to explain their punishment allocations. In two experiments (N = 195), 3- and 4-year-olds evaluated characters with distinct intentions to help or to hinder who were associated with either positive or negative outcomes. Both ages judged characters with more positive intentions as nicer, and allocated punishment to characters with more negative intentions; neither of these tendencies depended on the outcomes the characters were associated with. Three-year-olds’ responses were somewhat less consistent than were 4-year-olds’, in that 3-year-olds’ judgments were disrupted by ambiguous harmful intent. Notably, children’s social judgments were less consistent than their moral judgments. In a third and final experiment (N = 100), children evaluated characters with the same intention but who were associated with different outcomes. Children showed inconsistent responding across age and outcome valence, but only 4-year-olds evaluating two characters with positive intentions reliably responded based on outcome. When providing informative responses in all three studies, children most frequently explained their punishment allocations by appealing to the puppet’s (attempted) hindering action or failure to help. These findings raise questions as to what underlies different patterns of response across studies in the literature, and suggests that observing live interactions may facilitate young children’s intention-based moral judgments.

The early emergence of sociomoral evaluation: infants prefer prosocial others

Humans readily evaluate third-parties' prosocial and antisocial acts. Recent evidence reveals that this tendency emerges early in development-even preverbal infants selectively approach prosocial others and avoid antisocial ones. Rather than reflecting attraction toward or away from low-level characteristics of the displays or simple behavioral rules, infants are sensitive to characteristics of both the agents and recipients of prosocial and antisocial acts. Specifically, infants' preferences require that the recipients of positive and negative acts be social agents with clear unfulfilled goals, who have not previously harmed others. In addition, prosocial and antisocial agents must act intentionally, in the service of positive and negative goals. It is an open question whether these prosocial preferences reflect self-interested and/or moral concerns.

Foundations of infants' social group evaluations

Previous research has suggested that infants exhibit a preference for familiar over unfamiliar social groups (e.g., preferring individuals from their own language group over individuals from a foreign language group). However, because past studies often employ forced-choice procedures, it is not clear whether infants' intergroup preferences are driven by positivity toward members of familiar groups, negativity toward members of unfamiliar groups, or both. Across six experiments, we implemented a habituation procedure to independently measure infants' positive and negative evaluations of speakers of familiar and unfamiliar languages. We report that by 1 year of age, infants positively evaluate individuals who speak a familiar language, but do not negatively evaluate individuals who speak an unfamiliar language (Experiments 1 and 2). Several experiments rule out lower-level explanations (Experiments 3-6). Together these data suggest that children's early social group preferences may be shaped by positive evaluations of familiar group(s), rather than negative evaluations of unfamiliar groups.

Is Psychology Moving in the Right Direction? An Analysis of the Evidentiary Value Movement

The following article considers whether psychology is moving in the right direction by exploring the evidentiary value movement. Although the author considers the movement to be a net positive, she discusses concerns regarding the scope and tone of the discussions to date. She encourages the movement to consider heretofore underrepresented subfields and to reduce the use of negative tone.

Moral judgement by the disconnected left and right cerebral hemispheres: a split-brain investigation

Owing to the hemispheric isolation resulting from a severed corpus callosum, research on split-brain patients can help elucidate the brain regions necessary and sufficient for moral judgement. Notably, typically developing adults heavily weight the intentions underlying others' moral actions, placing greater importance on valenced intentions versus outcomes when assigning praise and blame. Prioritization of intent in moral judgements may depend on neural activity in the right hemisphere's temporoparietal junction, an area implicated in reasoning about mental states. To date, split-brain research has found that the right hemisphere is necessary for intent-based moral judgement. When testing the left hemisphere using linguistically based moral vignettes, split-brain patients evaluate actions based on outcomes, not intentions. Because the right hemisphere has limited language ability relative to the left, and morality paradigms to date have involved significant linguistic demands, it is currently unknown whether the right hemisphere alone generates intent-based judgements. Here we use nonlinguistic morality plays with split-brain patient J.W. to examine the moral judgements of the disconnected right hemisphere, demonstrating a clear focus on intent. This finding indicates that the right hemisphere is not only necessary but also sufficient for intent-based moral judgement, advancing research into the neural systems supporting the moral sense.

A Collaborative Approach to Infant Research: Promoting Reproducibility, Best Practices, and Theory-Building

The ideal of scientific progress is that we accumulate measurements and integrate these into theory, but recent discussion of replicability issues has cast doubt on whether psychological research conforms to this model. Developmental research-especially with infant participants-also has discipline-specific replicability challenges, including small samples and limited measurement methods. Inspired by collaborative replication efforts in cognitive and social psychology, we describe a proposal for assessing and promoting replicability in infancy research: large-scale, multi-laboratory replication efforts aiming for a more precise understanding of key developmental phenomena. The ManyBabies project, our instantiation of this proposal, will not only help us estimate how robust and replicable these phenomena are, but also gain new theoretical insights into how they vary across ages, linguistic communities, and measurement methods. This project has the potential for a variety of positive outcomes, including less-biased estimates of theoretically important effects, estimates of variability that can be used for later study planning, and a series of best-practices blueprints for future infancy research.

Young children remedy second- and third-party ownership violations

When responding to ownership violations, children can focus on the victim's needs, the perpetrator's punishment, or both. Recent studies show that 3- and 5-year-olds are equally likely to respond to second- and third-party violations, and 3-year-olds return objects to their rightful owners. Children's interventions are consistent with justice for victims.

Agency attribution in infancy: evidence for a negativity bias

Adults tend to attribute agency and intention to the causes of negative outcomes, even if those causes are obviously mechanical. Is this over-attribution of negative agency the result of years of practice with attributing agency to actual conspecifics, or is it a foundational aspect of our agency-detection system, present in the first year of life? Here we present two experiments with 6-month-old infants, in which they attribute agency to a mechanical claw that causes a bad outcome, but not to a claw that causes a good outcome. Control experiments suggest that the attribution stems directly from the negativity of the outcome, rather than from physical cues present in the stimuli. Together, these results provide evidence for striking developmental continuity in the attribution of agency to the causes of negative outcomes.

Moral Judgment and Action in Preverbal Infants and Toddlers

Although developmental psychologists traditionally explore morality from a learning and development perspective, some aspects of the human moral sense may be built-in, having evolved to sustain collective action and cooperation as required for successful group living. In this article, I review a recent body of research with infants and toddlers, demonstrating surprisingly sophisticated and flexible moral behavior and evaluation in a preverbal population whose opportunity for moral learning is limited at best. Although this work itself is in its infancy, it supports theoretical claims that human morality is a core aspect of human nature.

Not like me = bad: infants prefer those who harm dissimilar others

Adults tend to like individuals who are similar to themselves, and a growing body of recent research suggests that even infants and young children prefer individuals who share their attributes or personal tastes over those who do not. In this study, we examined the nature and development of attitudes toward similar and dissimilar others in human infancy. Across two experiments with combined samples of more than 200 infant participants, we found that 9- and 14-month-old infants prefer individuals who treat similar others well and treat dissimilar others poorly. A developmental trend was observed, such that 14-month-olds' responses were more robust than were 9-month-olds'. These findings suggest that the identification of common and contrasting personal attributes influences social attitudes and judgments in powerful ways, even very early in life.

The mentalistic basis of core social cognition: experiments in preverbal infants and a computational model

Evaluating individuals based on their pro- and anti-social behaviors is fundamental to successful human interaction. Recent research suggests that even preverbal infants engage in social evaluation; however, it remains an open question whether infants' judgments are driven uniquely by an analysis of the mental states that motivate others' helpful and unhelpful actions, or whether non-mentalistic inferences are at play. Here we present evidence from 10-month-olds, motivated and supported by a Bayesian computational model, for mentalistic social evaluation in the first year of life.A video abstract of this article can be viewed at http://youtu.be/rD_Ry5oqCYE.

Giving leads to happiness in young children

Evolutionary models of cooperation require proximate mechanisms that sustain prosociality despite inherent costs to individuals. The "warm glow" that often follows prosocial acts could provide one such mechanism; if so, these emotional benefits may be observable very early in development. Consistent with this hypothesis, the present study finds that before the age of two, toddlers exhibit greater happiness when giving treats to others than receiving treats themselves. Further, children are happier after engaging in costly giving--forfeiting their own resources--than when giving the same treat at no cost. By documenting the emotionally rewarding properties of costly prosocial behavior among toddlers, this research provides initial support for the claim that experiencing positive emotions when giving to others is a proximate mechanism for human cooperation.

Young infants prefer prosocial to antisocial others

The current study replicates and extends the finding (Hamlin, Wynn & Bloom, 2007) that infants prefer individuals who act prosocially toward unrelated third parties over those who act antisocially. Using different stimuli from those used by Hamlin, Wynn & Bloom (2007), somewhat younger subjects, and 2 additional social scenarios, we replicated the findings that (a) infants prefer those who behave prosocially versus antisocially, and (b) these preferences are based on the social nature of the actions. The generality of infants' responses across multiple examples of prosocial and antisocial actions supports the claim that social evaluation is fundamental to perceiving the world.

Three-month-olds show a negativity bias in their social evaluations

Previous research has shown that 6-month-olds evaluate others on the basis of their social behaviors--they are attracted to prosocial individuals, and avoid antisocial individuals (Hamlin, Wynn & Bloom, 2007). The current studies investigate these capacities prior to 6 months of age. Results from two experiments indicate that even 3-month-old infants evaluate others based on their social behavior towards third parties, and that negative social information is developmentally privileged.

Do as I do: 7-month-old infants selectively reproduce others' goals

In the current study, we tested whether 7-month-old infants would selectively imitate the goal-relevant aspects of an observed action. Infants saw an experimenter perform an action on one of two small toys and then were given the opportunity to act on the toys. Infants viewed actions that were either goal-directed or goal-ambiguous, and that represented either completed or uncompleted goals. Infants reproduced the goal of the experimenter only in those cases where the action was goal-directed, in both the complete and incomplete goal conditions. These results provide the first evidence that infants as young as 7 months of age selectively imitate actions based on their goal-directedness, and that they are able to analyze the goals of even uncompleted actions. Even during the first year of life, infants' sensitivity to goal-directed action is expressed not only in their responses in visual habituation procedures, but also in their overt actions.