When viewing pupil sizes change, our own pupil sizes change, a phenomenon known as pupillary contagion. This involuntary response is reliable between humans, but can be affected by familiarity and empathy. We investigated whether the pupillary contagion response occurs for humans viewing familiar species - cats and dogs - and whether it is modulated by preferences for particular species. Pupil sizes were measured while viewing cat, dog, and human images with small, medium, and large pupils. Trait empathy, cat and dog affiliation and experience were subsequently measured. There was an image pupil size effect, but this did not vary by species. There was greater pupil size change to cats and dogs than to humans, but this might have been due to the varying size and appearance of the cats and dogs. Greater dog affiliation was also associated with smaller overall pupil size change to dogs and larger change to humans, but this did not interact with image pupil size. Dog affiliation might be associated with less arousal to dog images. In sum, pupillary contagion responses indicate a spontaneous transfer of information about internal states and the findings suggest that humans are sensitive to this across species, regardless of individual preference.
In addition to controlling the influx of light to the retina, the pupil also reacts as a result of cognitive and emotional processing. This makes it possible to use pupil dilation as an index for cognitive effort and emotional arousal. We show how an extended version of a computational model of pupil dilation can account for pupillary contagion effects where the pupil of an observer dilates upon seeing another person with dilated pupils. We also show how the model can reproduce the effects of cognitive effort in a math exercise. Furthermore, we investigate how the model can account for different explanations for the abnormal pupil response seen in individuals with or at risk for autism spectrum disorder. The reported computer simulations illustrate the usefulness of system-level models of the brain in addressing complex cognitive and emotional phenomena.
From early in life, infants synchronize with others on a physiological level, a process thought to underlie social connections and group cohesion. This synchronization is seen, for example, when their pupils dilate in response to observing another person with dilated pupils – known as “pupillary contagion.” There is mixed evidence on whether arousal synchrony is modulated by interpersonal similarity factors, such as race, and even in studies that find such an effect, confounding visual factors could play a role. In the current study, language was used to manipulate interpersonal similarity for 10-month-old infants who saw speakers’ pupils dilate or constrict, while their own pupil size and gaze were assessed. Results from the first half of the study show that only own-language speakers elicited pupillary contagion and increased attention when their pupils dilated. While in the second half of the study, when infants’ level of attention was also decreasing, this effect did not hold. Together, the results indicate that infants’ sharing of arousal is modulated by shared language, though further research can help to clarify how these effects unfold over time.
Being sensitive and responsive to others’ internal states is critical for social life. One reliable cue to what others might be feeling is pupil dilation because it is linked to increases in arousal. When adults view an individual with dilated pupils, their pupils dilate in response, suggesting not only sensitivity to pupil size, but a corresponding response as well. However, little is known about the origins or mechanism underlying this phenomenon of pupillary contagion. Here we show that 4- to 6-month-old infants show pupillary contagion when viewing photographs of eyes with varying pupil sizes: their pupils dilate in response to others’ large, but not small or medium pupils. The results suggest that pupillary contagion is likely driven by a transfer of arousal and that it is present very early in life in human infants, supporting the view that it could be an adaptation fundamental for social and emotional development.
We demonstrate that 18-month-olds, but not 14-month-olds, can anticipate others' actions based on an interpretation of shared goals that bind together individual actions into a collaborative sequence. After viewing a sequence of actions performed by two people who socially interact, 18-month-olds bound together the socially engaged actors' actions such that they later expected the actors to share the same final goal. Eighteen-month-olds who saw nonsocially engaged actors did not have this expectation and neither did 14-month-olds when viewing either socially or nonsocially engaged actors. The results are discussed in light of the possibility that experience in collaborations could be necessary for understanding collaboration from a third-person perspective.
Eye tracking was used to show that 18-month-old infants are sensitive to social context as a sign that others' actions are bound together as a collaborative sequence based on a joint goal. Infants observed five identical demonstrations in which Actor 1 moved a block to one location and Actor 2 moved the same block to a new location, creating a sequence of actions that could be considered either individual actions or collaboration. In the test phase, Actor 1 was alone and sitting so that she could reach both locations. The question was whether she would place a new block in the location she had previously (individual goal) or in the location that could be considered the goal of collaboration (joint goal). Importantly, in the Social condition, the actors were socially engaged with each other before and during the demonstration, while in the Non-Social condition, they were not. Results revealed that infants in the Social condition spontaneously anticipated Actor 1 placing her block in the joint goal location more often than those in the Non-Social condition. Thus, the social context seems to allow infants to bind actions into a collaborative sequence and anticipate joint rather than individual goals, giving insight into how actions are perceived using top-down processing early in life.
Abstract Infants show remarkable skills for processing music in the first year of life. Such skills are believed to foster social and communicative development, yet little is known about how infants? own preferences for music develop and whether social information plays a role. Here, we investigate whether the reactions of another person influence infants? responses to music. Specifically, 12-month-olds (N = 33) saw an actor react positively or negatively after listening to clips of instrumental music. Arousal (measured via pupil dilation) and attention (measured via looking time) were assessed when infants later heard the clips without the actor visible. Results showed greater pupil dilation when listening to music clips that had previously been reacted to negatively than those that had been reacted to positively (Exp. 1). This effect was not replicated when a similar, rather than identical, clip from the piece of music was used in the test phase (Exp. 2, N = 35 12-month-olds). There were no effects of the actor's positive or negative reaction on looking time. Together, our findings suggest that infants are sensitive to others? positive and negative reactions not only for concrete objects, such as food or toys, but also for more abstract stimuli including music.
In the current eye-tracking study, we explored whether 12-month-old infants can predict others' social preferences. We showed infants scenes in which two characters alternately helped or hindered an agent in his goal of climbing a hill. In a control condition, the two characters moved up and down the hill in identical ways to the helper and hinderer but did not make contact with the agent; thus, they did not cause him to reach or not reach his goal. Following six alternating familiarization trials of helping and hindering interactions (helphinder condition) or up and down interactions (updown condition), infants were shown one test trial in which they could visually anticipate the agent approaching one of the two characters. As predicted, infants in the helphinder condition made significantly more visual anticipations toward the helping than hindering character, suggesting that they predicted the agent to approach the helping character. In contrast, infants revealed no difference in visual anticipations between the up and down characters. The updown condition served to control for low-level perceptual explanations of the results for the helphinder condition. Thus, together the results reveal that 12-month-old infants make predictions about others' behaviour and social preferences from a third-party perspective.
Across two experiments, we examined the relationship between 18-month-old infants' mimicry and social behavior - particularly invitations to play with an adult play partner. In Experiment 1, we manipulated whether an adult mimicked the infant's play or not during an initial play phase. We found that infants who had been mimicked were subsequently more likely to invite the adult to join their play with a new toy. In addition, they reen-acted marginally more steps from a social learning demonstration she gave. In Experiment 2, infants had the chance to spontaneously mimic the adult during the play phase. Complementing Experiment 1, those infants who spent more time mimicking the adult were more likely to invite her to play with a new toy. This effect was specific to play and not apparent in other communicative acts, such as directing the adult's attention to an event or requesting toys. Together, the results suggest that infants use mimicry as a tool to establish social connections with others and that mimicry has specific influences on social behaviors related to initiating subsequent joint interactions.
Infants imitate others' individual actions, but do they also replicate others' joint activities? To examine whether observing joint action influences infants' initiation of joint action, forty-eight 18-month-old infants observed object demonstrations by 2 models acting together (joint action), 2 models acting individually (individual action), or 1 model acting alone (solitary action). Infants' behavior was examined after they were given each object. Infants in the joint action condition attempted to initiate joint action more often than infants in the other conditions, yet they were equally likely to communicate for other reasons and to imitate the demonstrated object-directed actions. The findings suggest that infants learn to replicate others' joint activity through observation, an important skill for cultural transmission of shared practices.
Sensitivity to others' emotional signals is an important factor for social interaction. While many studies of emotional reactivity focus on facial emotional expressions, signals such as pupil dilation which can indicate arousal, may also affect observers. For example, observers' pupils dilate when viewing someone with dilated pupils, so-called pupillary contagion. Yet it is unclear how pupil size and emotional expression interact as signals. Further, examining individual differences in emotional reactivity to others can shed light on its mechanisms and potential outcomes. In the current study, adults' (N = 453) pupil size was assessed while they viewed images of the eye region of individuals varying in emotional expression (neutral, happy, sad, fearful, angry) and pupil size (large, medium, small). Participants showed pupillary contagion regardless of the emotional expression. Individual differences in demographics (gender, age, socioeconomic status) and psychosocial factors (anxiety, depression, sleep problems) were also examined, yet the only factor related to pupillary contagion was socioeconomic status, with higher socioeconomic status predicting less pupillary contagion for emotionally-neutral stimuli. The results suggest that while pupillary contagion is a robust phenomenon, it can vary meaningfully across individuals.
Infants socially engage with others and observe others' social interactions from early in life. One characteristic found to be important for signaling and establishing affiliative social relationships is physical coordination and synchronization of movements. This study investigated whether synchrony in others' movements signals affiliation to 12- and 15-month-old infants. The infants were shown a scene in which two characters moved either synchronously or non-synchronously with a third character in the center. Next, the center character made an affiliation declaration and subsequently approached and cuddled one of the two characters. Using measures of gaze, we gauged infants' inferences about whom the center character would affiliate with before the cuddling took place. We found that 15-month-olds, but not 12-month-olds, inferred that the center character would affiliate with the previously synchronous character, suggesting that they can make inferences about others' affiliation based on movement synchrony. The findings are discussed in terms of their relevance to the infants' personal preferences and the potential importance of first-person experience in the development of social cognition.
Pupillary contagionresponding to pupil size observed in other people with changes in one's own pupilhas been found in adults and suggests that arousal and other internal states could be transferred across individuals using a subtle physiological cue. Examining this phenomenon developmentally gives insight into its origins and underlying mechanisms, such as whether it is an automatic adaptation already present in infancy. In the current study, 6- and 9-month-olds viewed schematic depictions of eyes with smaller and larger pupilspairs of concentric circles with smaller and larger black centerswhile their own pupil sizes were recorded. Control stimuli were comparable squares. For both age groups, infants' pupil size was greater when they viewed large-center circles than when they viewed small-center circles, and no differences were found for large-center compared with small-center squares. The findings suggest that infants are sensitive and responsive to subtle cues to other people's internal states, a mechanism that would be beneficial for early social development.
BACKGROUND: How is the perception of collaboration influenced by individual characteristics, in particular high levels of callous-unemotional (CU) traits? CU traits are associated with low empathy and endorsement of negative social goals such as dominance and forced respect. Thus, it is possible that they could relate to difficulties in interpreting that others are collaborating based on a shared goal.
METHODS: In the current study, a community sample of 15- to 16-year olds participated in an eye tracking task measuring whether they expect that others engaged in an action sequence are collaborating, depending on the emotion they display toward each other. Positive emotion would indicate that they share a goal, while negative emotion would indicate that they hold individual goals.
RESULTS: When the actors showed positive emotion toward each other, expectations of collaboration varied with CU traits. The higher adolescents were on CU traits, the less likely they were to expect collaboration. When the actors showed negative emotion toward each other, CU traits did not influence expectations of collaboration.
CONCLUSIONS: The findings suggest that CU traits are associated with difficulty in perceiving positive social interactions, which could further contribute to the behavioral and emotional problems common to those with high CU traits.
Infant engagement during guided play is a reliable indicator of early learning outcomes, psychiatric issues and familial wellbeing. An obstacle to using such information in real-world scenarios is the need for a domain expert to assess the data. We show that an end-to-end Deep Learning approach can perform well in automatic infant engagement detection from a single video source, without requiring a clear view of the face or the whole body. To tackle the problem of explainability in learning methods, we evaluate how four common attention mapping techniques can be used to perform subjective evaluation of the network’s decision process and identify multimodal cues used by the network to discriminate engagement levels. We further propose a quantitative comparison approach, by collecting a human attention baseline and evaluating its similarity to each technique.
Infant engagement during play is an active area of research, relatedto the development of cognition. Automatic detection of engagementcould benefit the research process, but existing techniquesused for automatic affect detection are unsuitable for this scenario,since they rely on the automatic extraction of facial and posturalfeatures trained on clear video capture of adults. This study showsthat end-to-end Deep Learning methods can successfully detectengagement of infants, without the need of clear facial video, whentrained for a specific interaction task. It further shows that attentionmapping techniques can provide explainability, thereby enablingtrust and insight into a model’s reasoning process.
Early childhood educators’ math anxiety and its relation to their frequency of pedagogic actions was examined through a questionnaire completed by 352 participants (aged 21–65) representative of the Swedish municipality where the study was conducted. Our sample contained 189 certified preschool teachers and 163 preschool caregivers who significantly differed in their ratings reported for math teaching anxiety. Results revealed that certified preschool teachers who reported higher levels of math anxiety also reported teaching and talking about mathematics content less frequently. When controlling for certified preschool teachers’ gender and age, years of work in preschools, and whether they work only with younger (1–3), older (4–6) or with both groups of children (1–6-year-old), certified preschool teachers’ general math anxiety and math teaching anxiety predicted their reported frequency of math teaching and frequency of conversations about numbers, patterns, and geometric concepts with peak strength in gatherings, excursions and situations designed to teach mathematics to preschool children. Preschool caregivers’ math anxiety measures and their reported frequency of pedagogic actions did not display statistically significant relations. Findings showed setting specific associations between certified preschool teachers general math anxiety, math teaching anxiety and their avoidance of mathematics content, highlighting the importance of early childhood educators’ awareness of math anxiety, its nature, and consequences for teaching practices.
The theory of natural pedagogy stipulates that infants follow gaze because they are sensitive to the communicative intent of others. According to this theory, gaze following should be present if, and only if, accompanied by at least one of a set of specific ostensive cues. The current article demonstrates gaze following in a range of contexts, both with and without expressions of communicative intent in a between-subjects design with a large sample of 6-month-old infants (n = 94). Thus, conceptually replicating prior results from Szufnarowska et al. (2014) and falsifying a central pillar of the natural pedagogy theory. The results suggest that there are opportunities to learn from others’ gaze independently of their displayed communicative intent.
Previous studies on conformity have primarily focused on factors that moderate conformity rates overall and paid little attention to explaining the individual differences. In this study, we investigate five-factor model personality traits of both parents and children and experimentally elicited conformity in 3.5-year-olds (N = 59) using an Asch-like paradigm with which we measure both overt conformity (public responses) and covert opinions (private beliefs after conformist responses): A correct covert opinion after an incorrect conformist response results from a socially normative motivation, whereas an incorrect covert opinion results from an informational motivation. Our data show (1) low parental extroversion is associated with participants' overall rate of conformity, (2) and low participant extroversion and high openness are associated with an informational instead of a normative motivation to conform. This suggests that sensitivity to the social context or social engagement level, as manifested through extroversion, could be an important factor in conformist behaviour.
Children, just like adults, conform to peer testimony when making ostensibly easy decisions. Yet, some are more prone to conform than others and little is known about which factors contribute to this variability. In the current study, we aimed to investigate the reasons for individual differences in conformity by examining potential correlates of experimentally-elicited conformity in a sample of Swedish 3.5-year-olds (N = 55; 56%girls). Specifically, we asked whether conformity was socialized by parents via their parental style and whether conformity is correlated with the behaviors of anonymous sharing or obedience, which might each share a common motivation with conformity. Our data showed that children’s conformity was associated with fathers’, but not mothers’, authoritarian parental style and with anonymous sharing, but not obedience. The findings lend support to the notions that authoritarian parental style encourages conformist behavior, and that conformity is correlated with anonymous sharing behavior.
Previous studies on conformity have primarily focused on factors that moderate conformity rates overall and paid little attention to explaining the individual differences. In the current study we investigate five factor model personality traits of both parents and children and experimentally-elicited conformity in 3.5-year-olds (N=59) using an Asch-like paradigm with which we measure both overt conformity (public responses) and covert opinions (private beliefs after conformist responses): A correct covert opinion after an incorrect conformist response results from a socially normative motivation whereas an incorrect covert opinion results from an informational motivation. Our data show (1) low parental extroversion is associated with participants’ overall rate of conformity; (2) and low participant extroversion and high openness are associated with an informational instead of a normative motivation to conform. This suggests that sensitivity to the social context or social engagement level, as manifested through extroversion, could be an important factor in conformist behaviour.
Typically developing humans automatically synchronize their arousal levels, resulting in pupillary contagion, or spontaneous adaptation of pupil size to that of others. This phenomenon emerges in infancy and is believed to facilitate social interaction. Williams syndrome (WS) is a genetic condition characterized by a hyper-social personality and social interaction challenges. Pupillary contagion was examined in individuals with WS (n=44), age-parallel-matched typically developing children and adults (n=65), and infants (n=79). Bayesian statistics were used. As a group, people with WS did not show pupillary contagion (Bayes factors supporting the null: 25-50) whereas control groups did. This suggests a very early emerging atypical developmental trajectory. In WS, higher pupillary contagion was associated with lower autistic symptoms of social communication. Diminished synchronization of arousal may explain why individuals with WS have social challenges, whereas synchronization of arousal is not a necessary correlate of high social motivation.
Recent work has shown that young children can learn about preferences by observing the choices and emotional reactions of other people, but there is no unified account of how this learning occurs. We show that a rational model, built on ideas from economics and computer science, explains the behavior of children in several experiments, and offers new predictions as well. First, we demonstrate that when children use statistical information to learn about preferences, their inferences match the predictions of a simple econometric model. Next, we show that this same model can explain children's ability to learn that other people have preferences similar to or different from their own and use that knowledge to reason about the desirability of hidden objects. Finally, we use the model to explain a developmental shift in preference understanding.
Williams syndrome (WS) is a rare genetic condition associated with high sociability, intellectual disability, and social cognitive challenges. Attention to others' eyes is crucial for social understanding. Orienting to, and from other’s eyes was studied in WS (n = 37, mean age = 23, age range 9–53). The WS group was compared to a typically developing comparison participants (n = 167) in stratified age groups from infancy to adulthood. Typically developing children and adults were quicker and more likely to orient to eyes than the mouth. This bias was absent in WS. The WS group had reduced peak saccadic velocities, indicating hypo-arousal. The current study indicates reduced orienting to others’ eyes in WS, which may affect social interaction skills.
To test how early social environments affect children's consideration of gender, 3- to 6-year-old children (N = 80) enrolled in gender-neutral or typical preschool programs in the central district of a large Swedish city completed measures designed to assess their gender-based social preferences, stereotypes, and automatic encoding. Compared with children in typical preschools, a greater proportion of children in the gender-neutral school were interested in playing with unfamiliar other-gender children. In addition, children attending the gender-neutral preschool scored lower on a gender stereotyping measure than children attending typical preschools. Children at the gender-neutral school, however, were not less likely to automatically encode others' gender. The findings suggest that gender-neutral pedagogy has moderate effects on how children think and feel about people of different genders but might not affect children's tendency to spontaneously notice gender.
According to natural pedagogy theory, infants are sensitive to particular ostensive cues that communicate to them that they are being addressed and that they can expect to learn referential information. We demonstrate that 6-month-old infants follow others' gaze direction in situations that are highly attention-grabbing. This occurs irrespective of whether these situations include communicative intent and ostensive cues (a model looks directly into the child's eyes prior to shifting gaze to an object) or not (a model shivers while looking down prior to shifting gaze to an object). In contrast, in less attention-grabbing contexts in which the model simply looks down prior to shifting gaze to an object, no effect is found. These findings demonstrate that one of the central pillars of natural pedagogy is false. Sensitivity to gaze following in infancy is not restricted to contexts in which ostensive cues are conveyed.
Infants expect people to direct actions toward objects, and they respond to actions directed to themselves, but do they have expectations about actions directed to third parties? In two experiments, we used eye tracking to investigate 1- and 2-year-olds' expectations about communicative actions addressed to a third party. Experiment 1 presented infants with videos where an adult (the Emitter) either uttered a sentence or produced non-speech sounds. The Emitter was either face-to-face with another adult (the Recipient) or the two were back-to-back. The Recipient did not respond to any of the sounds. We found that 2-, but not 1-year-olds looked quicker and longer at the Recipient following speech than non-speech, suggesting that they expected her to respond to speech. These effects were specific to the face-to-face context. Experiment 2 presented 1-year-olds with similar face-to-face exchanges but modified to engage infants and minimize task demands. The infants looked quicker to the Recipient following speech than non-speech, suggesting that they expected a response to speech. The study suggests that by 1 year of age infants expect communicative actions to be directed at a third-party listener.
We investigated 14-month-old infants' expectations toward a third party addressee of communicative gestures and an instrumental action. Infants' eye movements were tracked as they observed a person (the Gesturer) point, direct a palm-up request gesture, or reach toward an object, and another person (the Addressee) respond by grasping it. Infants' looking patterns indicate that when the Gesturer pointed or used the palm-up request, infants anticipated that the Addressee would give the object to the Gesturer, suggesting that they ascribed a motive of request to the gestures. In contrast, when the Gesturer reached for the object, and in a control condition where no action took place, the infants did not anticipate the Addressee's response. The results demonstrate that infants' recognition of communicative gestures extends to others' interactions, and that infants can anticipate how third-party addressees will respond to others' gestures.
Callous-unemotional (CU) traits are associated with lower emotional reactivity in adolescents. However, since previous studies have focused mainly on reactivity to negative stimuli, it is unclear whether reactivity to positive stimuli is also affected. Further, few studies have addressed the link between CU traits and emotional reactivity in longitudinal community samples, which is important for determining its generalizability and developmental course. In the current study, pupil dilation and self-ratings of arousal and valence were assessed in 100 adolescents (15-17 years) from a community sample, while viewing images with negative and positive valence from the International Affective Pictures System (ZAPS). Behavioral traits (CU) were assessed concurrently, as well as at ages 12-15, and 8-9 (subsample, n = 68, low levels of prosocial behavior were used as a proxy for CU traits). The results demonstrate that CU traits assessed at ages 12-15 and 8-9 predicted less pupil dilation to both positive and negative images at ages 15-17. Further, CU traits at ages 12-15 and concurrently were associated with less negative valence ratings for negative images and concurrently to less positive valence ratings for positive images. The current findings demonstrate that CU traits are related to lower emotional reactivity to both negative and positive stimuli in adolescents from a community sample.
Matching the timing of one's movements to the movements of others has been proposed to increase affiliation and prosociality. Although coordinated movements facilitate early social interactions, not much is known about the mechanisms and effects of movement synchrony throughout development. Two studies investigated 12-month-olds' (Study 1, N=40) and 9-month-olds' (Study 2, N=41) preferences for synchronous others in a social as opposed to a nonsocial context. It was found that movement synchrony exclusively guides infants' social choices at 12months. In contrast, 9-month-olds did not show any preferences for synchronous movements in social or nonsocial contexts. Results suggest that movement synchrony is important in guiding infants' social preferences and its effects emerge toward the end of the 1st year of life.
Moving in time to others, as is often observed in dance, music, sports and much of children’s play cross-culturally, is thought to make people feel and act more prosocially towards each other. In a recent paper, Atwood et al. (2022) argued that the inferential validity of this link found between synchronous behaviour and prosociality might be mainly due to “expectancy effects generated by a combination of (1) experimenter expectancy, leading to experimenter bias; and (2) participant expectancy (i.e., placebo effects)”. Here, we counter these arguments with (1) examples of studies devoid of experimenter expectancy effects that nevertheless demonstrate a positive link between synchrony and prosociality, and (2) insights from the developmental literature that address participant expectancy by showing how expectations formed through lived experiences of synchronous interactions do not necessarily threaten inferential validity. In conclusion, there is already sufficient good-quality evidence showing the positive effects of synchronous behaviours on prosociality beyond what can be explained by experimenter or participant expectation effects.