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.

False belief understanding in deaf children: what are the difficulties?

Children with cochlear implants (CIs) demonstrate proficiency in verbal-story elicited-response (VS-ER) false-belief tasks, such as the Sally & Ann task, at a similar age as typically developing hearing children. However, they face challenges in non-verbal spontaneous-response (NV-SR) false-belief tasks, measured via looking times, which hearing infants typically pass by around 2 years of age, or earlier. The purpose of the present study was to examine whether these difficulties remain in a non-verbal-story elicited-response (NVS-ER) false-belief task, in which children are offered the opportunity to provide an elicited response to a non-verbal-story task. A total of thirty 4- to 8-year-old children with CI-s and hearing children completed three different kinds of false-belief tasks. The results showed that children with CI-s performed above chance level on the verbal task (i.e., VS-ER task), but not on the two non-verbal tasks, (i.e., NVS-ER and NV-SR tasks). The control group of typically developing hearing children performed above chance on all three kinds of tasks (one-tailed significance level). Our findings highlight the importance of external narrative support for children with CIs in tasks that involve mental perspective-taking, and specifically predicting actions based on false beliefs.

Belief attribution in deaf and hearing infants.

Based on anticipatory looking and reactions to violations of expected events, infants have been credited with 'theory of mind' (ToM) knowledge that a person's search behaviour for an object will be guided by true or false beliefs about the object's location. However, little is known about the preconditions for looking patterns consistent with belief attribution in infants. In this study, we compared the performance of 17- to 26-month-olds on anticipatory looking in ToM tasks. The infants were either hearing or were deaf from hearing families and thus delayed in communicative experience gained from access to language and conversational input. Hearing infants significantly outperformed their deaf counterparts in anticipating the search actions of a cartoon character that held a false belief about a target-object location. By contrast, the performance of the two groups in a true belief condition did not differ significantly. These findings suggest for the first time that access to language and conversational input contributes to early ToM reasoning.

Cross-cultural differences in early expectations about third party resource distribution.

Research using non-verbal looking-time methods suggests that pre-verbal infants are able to detect inequality in third party resource allocations. However, nothing is known about the emergence of this capacity outside a very narrow Western context. We compared 12- to 20-month-old infants (N = 54) from one Western and two non-Western societies. Swedish infants confirmed the pattern from previous Western samples by looking longer at the unequal distribution, suggesting that they expected the resources to be distributed equally. Samburu infants looked longer at the equal distribution, suggesting an expectation of unequal distribution. The Kikuyu infants looked equally at both distributions, and did not show any specific exactions. These results suggest that expectations of equal distributions in third party allocations are affected by experience of cultural variations of distributive norms and social interaction early in development.

Infants Consider the Distributor's Intentions in Resource Allocation.

Recent experimental studies suggest that preverbal infants are able to evaluate agents on the basis of their distributive actions. Here we asked whether such evaluations are based on infants' understanding of the distributors' intentions, or only the outcome of their actions. Ten-month-old infants observed animated movies of unequal resource allocations by distributors who attempted but failed to distribute resources equally or unequally between two individuals. We found that infants attended longer to the test event showing a third agent approaching a distributor who was unable to make an unequal distribution, compared to the test event where the third agent approached a distributor who was unable to make an equal distribution of resources. Our results suggest that infants' ability to encode distributive actions goes beyond an analysis of the outcome of these actions, by including the intentions of the distributors whose actions lead to these outcomes.

Do Infants Attribute Moral Traits? Fourteen-Month-Olds' Expectations of Fairness Are Affected by Agents' Antisocial Actions.

We investigated whether and how infants link the domains of harm, help and fairness. Fourteen-month-old infants were familiarized with a character that either helped or hindered another agent's attempts to reach the top of a hill. Then, in the test phase they saw the helper or the hinderer carrying out an equal or an unequal distribution toward two identical recipients. Infants who saw the helper performing an unequal distribution looked longer than those who saw the helper performing an equal distribution, whereas infants who saw the hinderer performing an unequal distribution looked equally long than those who saw the hinderer performing an equal distribution. These results suggest that infants linked the hindering actions to a diminished propensity for distributive fairness. This provides support for theories that posit an early emerging ability to attribute moral traits to agents and to generate socio-moral evaluations of their actions. RESEARCH HIGHLIGHTS  - Infants expect agents that previously helped another agent to perform egalitarian distributions, but they do not generate such expectation about agents that previously hindered another agent. - This ability to link hindering and distributive actions is important because it may help the development of reasoning about agents' stable moral traits. - Results provide support for recent theories on early social evaluation skills and they constraint theories on the acquisition of moral competence.

Language access and theory of mind reasoning: evidence from deaf children in bilingual and oralist environments.

This investigation examined whether access to sign language as a medium for instruction influences theory of mind (ToM) reasoning in deaf children with similar home language environments. Experiment 1 involved 97 deaf Italian children ages 4-12 years: 56 were from deaf families and had LIS (Italian Sign Language) as their native language, and 41 had acquired LIS as late signers following contact with signers outside their hearing families. Children receiving bimodal/bilingual instruction in LIS together with Sign-Supported and spoken Italian significantly outperformed children in oralist schools in which communication was in Italian and often relied on lipreading. Experiment 2 involved 61 deaf children in Estonia and Sweden ages 6-16 years. On a wide variety of ToM tasks, bilingually instructed native signers in Estonian Sign Language and spoken Estonian succeeded at a level similar to age-matched hearing children. They outperformed bilingually instructed late signers and native signers attending oralist schools. Particularly for native signers, access to sign language in a bilingual environment may facilitate conversational exchanges that promote the expression of ToM by enabling children to monitor others' mental states effectively.

Early conversational environment enables spontaneous belief attribution in deaf children.

Previous research suggests that deaf children who grow up with hearing parents display considerable difficulties in understanding mental states of others, up to their teenage years when explicitly asked in a verbal test situation (Meristo et al., 2007). On the other hand, typically developing pre-verbal infants display evidence of spontaneous false belief attribution when tested in looking-time tasks, although verbal tests are typically not passed before the age of 4years (Onishi & Baillargeon, 2005). The purpose of the present study was to examine whether deaf children of hearing parents are able to demonstrate spontaneous belief attribution in a non-verbal eye-tracking task. Thirty 4- to 8-year-old, deaf and hearing children, completed a non-verbal spontaneous-response false-belief task and a verbal elicited-response false-belief task. The deaf children were either children with cochlear implants or children with hearing aids. Comparative analyses were also carried out with a previous sample of deaf and hearing 2-year-olds (reported in Meristo, Morgan, et al., 2012). We found that in the non-verbal spontaneous-response task typically hearing children, but not deaf children, were able to predict that a person with a false belief about an object's location will search erroneously for the object. However, hearing children and deaf children with implants, but not deaf children with hearing aids, passed the verbal elicited-response task. Language development was significantly correlated with both types of false-belief tasks for the whole sample. Our findings strengthen the hypothesis that the emergence of the ability to recognize others' beliefs needs to be supported initially by very early conversational input in dialogues with caregivers.

Infants distinguish antisocial actions directed towards fair and unfair agents.

Three experiments provide evidence of an incipient sense of fairness in preverbal infants. Ten-month-old infants were shown cartoon videos with two agents, the 'donors', who distributed resources to two identical recipients. One donor always distributed the goods equally, while the other performed unequal distributions by giving everything to one recipient. In the test phase, a third agent hit or took resources away from either the fair or the unfair donor. We found that infants looked longer when the antisocial actions were directed towards the unfair rather than the fair donor. These findings support the view that infants are able to evaluate agents based on their distributive actions and suggest that the foundations of human socio-moral competence are acquired independently of parental feedback and linguistic experience.

Do infants detect indirect reciprocity?

In social interactions involving indirect reciprocity, agent A acts prosocially towards B and this prompts C to act prosocially towards A. This happens because A's actions enhanced its reputation in the eyes of third parties. Indirect reciprocity may have been of central importance in the evolution of morality as one of the major mechanisms leading to the selection of helping and fair attitudes. Here we show that 10-month-old infants expect third parties to act positively towards fair donors who have distributed attractive resources equally between two recipients, rather than toward unfair donors who made unequal distributions. Infants' responses were dependent on the reciprocator's perceptual exposure to previous relevant events: they expected the reciprocator to reward the fair donor only when it had seen the distributive actions performed by the donors. We propose that infants were able to generate evaluations of agents that were based on the fairness of their distributive actions and to generate expectations about the social preferences of informed third parties.