Longitudinal stability and change across a year in children's gender stereotypes about four different STEM fields.

Gender stereotypes about science, technology, engineering, and math (STEM) are salient for children and adolescents and contribute to achievement-related disparities and inequalities in STEM participation. However, few studies have used a longitudinal design to examine changes in gender stereotypes across a range of STEM fields. In a large, preregistered study, we examined the developmental trajectories of two gender stereotypes (involving interest and ability) in four STEM fields across three time points within a calendar year, starting in Grades 2-8. The diverse sample included 803 students ages 7-15 years old at the start of the study (50% girls; 8.5% Asian, 6.0% Black, 25.5% Hispanic/Latinx, 43.7% White, and 16.3% other). Multilevel growth modeling was used to examine developmental trajectories in students' stereotypes for four STEM fields (math, science, computer science, and engineering) while considering both gender and grade level. We found that different STEM disciplines displayed different developmental patterns: Math ability and science interest stereotypes more strongly favored girls over the year among elementary school participants, whereas computer science stereotypes less strongly favored boys over time, and engineering stereotypes (which largely favored boys) were stable across time. The results highlight that the development of stereotypes is not the same for all STEM fields as well as the need to understand the complexity and specificity of developmental change across fields and types of stereotypes. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Heart-to-heart: infant heart rate at 3 months is linked to infant-directed speech, mother-infant interaction, and later language outcomes.

Introduction: Previous studies underscore the importance of speech input, particularly infant-directed speech (IDS) during one-on-one (1:1) parent-infant interaction, for child language development. We hypothesize that infants' attention to speech input, specifically IDS, supports language acquisition. In infants, attention and orienting responses are associated with heart rate deceleration. We examined whether individual differences in infants' heart rate measured during 1:1 mother-infant interaction is related to speech input and later language development scores in a longitudinal study. Methods: Using a sample of 31 3-month-olds, we assessed infant heart rate during mother-infant face-to-face interaction in a laboratory setting. Multiple measures of speech input were gathered at 3 months of age during naturally occurring interactions at home using the Language ENvironment Analysis (LENA) system. Language outcome measures were assessed in the same children at 30 months of age using the MacArthur-Bates Communicative Development Inventory (CDI). Results: Two novel findings emerged. First, we found that higher maternal IDS in a 1:1 context at home, as well as more mother-infant conversational turns at home, are associated with a lower heart rate measured during mother-infant social interaction in the laboratory. Second, we found significant associations between infant heart rate during mother-infant interaction in the laboratory at 3 months and prospective language development (CDI scores) at 30 months of age. Discussion: Considering the current results in conjunction with other converging theoretical and neuroscientific data, we argue that high IDS input in the context of 1:1 social interaction increases infants' attention to speech and that infants' attention to speech in early development fosters their prospective language growth.

Mother-infant social and language interactions at 3 months are associated with infants' productive language development in the third year of life.

Previous studies underscore the importance of social interactions for child language development-particularly interactions characterized by maternal sensitivity, infant-directed speech (IDS), and conversational turn-taking (CT) in one-on-one contexts. Although infants engage in such interactions from the third month after birth, the prospective link between speech input and maternal sensitivity in the first half year of life and later language development has been understudied. We hypothesized that social interactions embodying maternal sensitivity, IDS and CTs in the first 3 months of life, are significantly associated with later language development and tested this using a longitudinal design. Using a sample of 40 3-month-old infants, we assessed maternal sensitivity during a structured mother-infant one-on-one (1:1) interaction based on a well-validated scoring system (the Coding Interactive Behavior system). Language input (IDS, CT) was assessed during naturally occurring interactions at home using the Language ENvironment Analysis (LENA) system. Language outcome measures were obtained from 18 to 30 months of age using the MacArthur-Bates Communicative Development Inventory. Three novel findings emerged. First, maternal sensitivity at 3 months was significantly associated with infants' productive language scores at 18, 21, 24, 27, and 30 months of age. Second, LENA-recorded IDS during mother-infant 1:1 interaction in the home environment at 3 months of age was positively correlated with productive language scores at 24, 27, and 30 months of age. Third, mother-infant CTs during 1:1 interaction was significantly associated with infants' productive language scores at 27 and 30 months of age. We propose that infants' social attention to speech during this early period-enhanced by sensitive maternal one-on-one interactions and IDS-are potent factors in advancing language development.

Infants' brain responses to social interaction predict future language growth.

In face-to-face interactions with infants, human adults exhibit a species-specific communicative signal. Adults present a distinctive "social ensemble": they use infant-directed speech (parentese), respond contingently to infants' actions and vocalizations, and react positively through mutual eye-gaze and smiling. Studies suggest that this social ensemble is essential for initial language learning. Our hypothesis is that the social ensemble attracts attentional systems to speech and that sensorimotor systems prepare infants to respond vocally, both of which advance language learning. Using infant magnetoencephalography (MEG), we measure 5-month-old infants' neural responses during live verbal face-to-face (F2F) interaction with an adult (social condition) and during a control (nonsocial condition) in which the adult turns away from the infant to speak to another person. Using a longitudinal design, we tested whether infants' brain responses to these conditions at 5 months of age predicted their language growth at five future time points. Brain areas involved in attention (right hemisphere inferior frontal, right hemisphere superior temporal, and right hemisphere inferior parietal) show significantly higher theta activity in the social versus nonsocial condition. Critical to theory, we found that infants' neural activity in response to F2F interaction in attentional and sensorimotor regions significantly predicted future language development into the third year of life, more than 2 years after the initial measurements. We develop a view of early language acquisition that underscores the centrality of the social ensemble, and we offer new insight into the neurobiological components that link infants' language learning to their early brain functioning during social interaction.

Exploring whether and how Black and White parents talk with their children about race: M(ai)cro race conversations about Black Lives Matter.

Previous research on parent-led race conversations reports robust racial differences in the content of race conversations between Black and white parents. It was unknown, however, whether these racial differences shifted in the months immediately following the summer of 2020 when there was heightened public attention directed toward white parents, specifically, to talk with children about racism. In the present study, we investigated whether and how Black (n = 344) and white (n = 381) parents talked about Black Lives Matter (BLM) with their 8- to 11-year-old children. Overall, 80% of parents (n = 725) reported talking about BLM, but Black parents were significantly more likely to discuss BLM than white parents (p = .008). Further qualitative analysis of the content of parents' reports showed that Black parents were significantly more likely than white parents to provide responses about BLM that acknowledge racial inequality in society or explicitly affirm/support Black lives. White parents, in contrast, were significantly more likely to discuss BLM by focusing on equality but without acknowledging racial injustice or to provide responses that lacked clarity and/or substance. Using the m(ai)cro model of human development (Rogers, Niwa, et al., 2021), we discuss how parents' reported race conversations are shaped by the sociopolitical context and their role in disrupting (or perpetuating) systemic racism through socialization. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Am I a good person? Academic correlates of explicit and implicit self-esteem during early childhood.

Implicit and explicit self-esteem are not commonly measured in the same children. Using a cross-sectional design, data from 354 Croatian children (184 girls) in Grade 1 (Mage = 7.55 years) and Grade 5 (Mage = 11.58 years) were collected in Spring 2019. All children completed explicit and implicit self-esteem measures; math and language grades were obtained. For the explicit measure, older children showed lower self-esteem than younger children, and girls showed lower self-esteem than boys. For the implicit measure, there were no age effects, and girls showed higher self-esteem than boys. Although both types of self-esteem were positively associated with academic achievement, implicit self-esteem was associated more strongly with language than with math achievement. Discussion is provided about why self-esteem relates to academic achievement during childhood.

Differentiating Between Us & Them: Reduced In-Group Bias as a Novel Mechanism Linking Childhood Violence Exposure with Internalizing Psychopathology.

Strong in-group bonds, facilitated by implicit favoritism for in-group members (i.e., in-group bias), promote mental health across development. Yet, we know little about how the development of in-group bias is shaped by early-life experiences. Childhood violence exposure is known to alter social information processing biases. Violence exposure may also influence social categorization processes, including in-group biases, in ways that influence risk for psychopathology. We examined associations of childhood violence exposure with psychopathology and behavioral and neural indices of implicit and explicit bias for novel groups in children followed longitudinally across three time points from age 5 to 10 years old (n = 101 at baseline; n = 58 at wave 3). To instantiate in-group and out-group affiliations, youths underwent a minimal group assignment induction procedure, in which they were randomly assigned to one of two groups. Youth were told that members of their assigned group shared common interests (in-group) and members of the other group did not (out-group). In pre-registered analyses, violence exposure was associated with lower implicit in-group bias, which in turn was associated prospectively with higher internalizing symptoms and mediated the longitudinal association between violence exposure and internalizing symptoms. During an fMRI task examining neural responses while classifying in-group and out-group members, violence-exposed children did not exhibit the negative functional coupling between vmPFC and amygdala to in-group vs. out-group members that was observed in children without violence exposure. Reduced implicit in-group bias may represent a novel mechanism linking violence exposure with the development of internalizing symptoms.

Dual-MEG interbrain synchronization during turn-taking verbal interactions between mothers and children.

Verbal interaction and imitation are essential for language learning and development in young children. However, it is unclear how mother-child dyads synchronize oscillatory neural activity at the cortical level in turn-based speech interactions. Our study investigated interbrain synchrony in mother-child pairs during a turn-taking paradigm of verbal imitation. A dual-MEG (magnetoencephalography) setup was used to measure brain activity from interactive mother-child pairs simultaneously. Interpersonal neural synchronization was compared between socially interactive and noninteractive tasks (passive listening to pure tones). Interbrain networks showed increased synchronization during the socially interactive compared to noninteractive conditions in the theta and alpha bands. Enhanced interpersonal brain synchrony was observed in the right angular gyrus, right triangular, and left opercular parts of the inferior frontal gyrus. Moreover, these parietal and frontal regions appear to be the cortical hubs exhibiting a high number of interbrain connections. These cortical areas could serve as a neural marker for the interactive component in verbal social communication. The present study is the first to investigate mother-child interbrain neural synchronization during verbal social interactions using a dual-MEG setup. Our results advance our understanding of turn-taking during verbal interaction between mother-child dyads and suggest a role for social "gating" in language learning.

Social experiences and youth psychopathology during the COVID-19 pandemic: A longitudinal study.

The early stages of the COVID-19 pandemic and associated stay-at-home orders resulted in a stark reduction in daily social interactions for children and adolescents. Given that peer relationships are especially important during this developmental stage, it is crucial to understand the impact of the COVID-19 pandemic on social behavior and risk for psychopathology in children and adolescents. In a longitudinal sample (N=224) of children (7-10y) and adolescents (13-15y) assessed at three strategic time points (before the pandemic, during the initial stay-at-home order period, and six months later after the initial stay-at-home order period was lifted), we examine whether certain social factors protect against increases in stress-related psychopathology during the pandemic, controlling for pre-pandemic symptoms. Youth who reported less in-person and digital socialization, greater social isolation, and less social support had worsened psychopathology during the pandemic. Greater social isolation and decreased digital socialization during the pandemic were associated with greater risk for psychopathology after experiencing pandemic-related stressors. In addition, children, but not adolescents, who maintained some in-person socialization were less likely to develop internalizing symptoms following exposure to pandemic-related stressors. We identify social factors that promote well-being and resilience in youth during this societal event.

Early-childhood temperament moderates the prospective associations of coping with adolescent internalizing and externalizing symptoms.

While appraisal and coping are known to impact adolescent psychopathology, more vulnerable or resilient responses to stress may depend on individual temperament. This study examined early life temperament as a moderator of the prospective relations of pre-adolescent appraisal and coping with adolescent psychopathology. The sample included 226 (62% female, 14-15 years) adolescents with assessments starting at 3 years of age. Adolescents were predominately White (12% Black 9% Asian, 11% Latinx, 4% Multiracial, and 65% White). Observed early-childhood temperament (fear, frustration, executive control, and delay ability) were tested as moderators of pre-adolescent coping (active and avoidant) and appraisal (threat, positive) on internalizing and externalizing symptoms during the pandemic. Interaction effects were tested using regression in R. Sex and family context of stress were covariates. Early-childhood temperament was correlated with pre-adolescent symptoms, however, pre-adolescent appraisal and coping but not temperament predicted adolescent psychopathology. Frustration moderated the relations of active and avoidant coping and positive appraisal to symptoms such that coping and appraisal related to lower symptoms only for those low in frustration. Executive control moderated the associations of avoidant coping with symptoms such that avoidance reduced the likelihood of symptoms for youth low in executive control. Findings underscore the role of emotionality and self-regulation in youth adjustment, with the impact of coping differing with temperament. These findings suggest that equipping youth with a flexible assortment of coping skills may serve to reduce negative mental health outcomes.

Infant brain imaging using magnetoencephalography: Challenges, solutions, and best practices.

The excellent temporal resolution and advanced spatial resolution of magnetoencephalography (MEG) makes it an excellent tool to study the neural dynamics underlying cognitive processes in the developing brain. Nonetheless, a number of challenges exist when using MEG to image infant populations. There is a persistent belief that collecting MEG data with infants presents a number of limitations and challenges that are difficult to overcome. Due to this notion, many researchers either avoid conducting infant MEG research or believe that, in order to collect high-quality data, they must impose limiting restrictions on the infant or the experimental paradigm. In this article, we discuss the various challenges unique to imaging awake infants and young children with MEG, and share general best-practice guidelines and recommendations for data collection, acquisition, preprocessing, and analysis. The current article is focused on methodology that allows investigators to test the sensory, perceptual, and cognitive capacities of awake and moving infants. We believe that such methodology opens the pathway for using MEG to provide mechanistic explanations for the complex behavior observed in awake, sentient, and dynamically interacting infants, thus addressing core topics in developmental cognitive neuroscience.

Lower implicit self-esteem as a pathway linking childhood abuse to depression and suicidal ideation.

Identifying the potential pathways linking childhood abuse to depression and suicidal ideation is critical for developing effective interventions. This study investigated implicit self-esteem-unconscious valenced self-evaluation-as a potential pathway linking childhood abuse with depression and suicidal ideation. A sample of youth aged 8-16 years (N = 240) completed a self-esteem Implicit Association Test (IAT) and assessments of abuse exposure, and psychopathology symptoms, including depression, suicidal ideation, anxiety, and externalizing symptoms. Psychopathology symptoms were re-assessed 1-3 years later. Childhood abuse was positively associated with baseline and follow-up depression symptoms and suicidal ideation severity, and negatively associated with implicit self-esteem. Lower implicit self-esteem was associated with both depression and suicidal ideation assessed concurrently and predicted significant increases in depression and suicidal ideation over the longitudinal follow-up period. Lower implicit self-esteem was also associated with baseline anxiety, externalizing symptoms, and a general psychopathology factor (i.e. p-factor). We found an indirect effect of childhood abuse on baseline and follow-up depression symptoms and baseline suicidal ideation through implicit self-esteem. These findings point to implicit self-esteem as a potential mechanism linking childhood abuse to depression and suicidal ideation.

Exploring developmental changes in infant anticipation and perceptual processing: EEG responses to tactile stimulation.

There is an increasing interest in alpha-range rhythms in the electroencephalogram (EEG) in relation to perceptual and attentional processes. The infant mu rhythm has been extensively studied in the context of linkages between action observation and action production in infancy, but less is known about the mu rhythm in relation to cross-modal processes involving somatosensation. We investigated differences in mu responses to cued vibrotactile stimulation of the hand in two age groups of infants: From 6 to 7 months and 13 to 14 months. We were also interested in anticipatory neural responses in the alpha frequency range prior to tactile stimulation. Tactile stimulation of infants' left or right hand was preceded by an audiovisual cue signaling which hand would be stimulated. In response to the tactile stimulus, infants demonstrated significant mu desynchronization over the central areas contralateral to the hand stimulated, with higher mu peak frequency and greater contralateral mu desynchronization for older infants. Prior to the tactile stimulus, both age groups showed significant bilateral alpha desynchronization over frontocentral sites, which may be indicative of generalized anticipation of an upcoming stimulus. The findings highlight the potential of examining the sensorimotor mu rhythm in the context of infant attentional development.

Prosociality and health: Identification with all humanity is a replicable predictor of prosocial motivation for health behaviors.

The acute phase of the COVID-19 pandemic may have passed, but the pandemic remains a major worldwide health concern that demands continued vigilance. Are there individual differences that predict the motivation to continue to wear masks and to create physical distance in public? Previous research conducted early in the pandemic had suggested that a particular social identity-identification with all humanity-is one underlying factor that contributes to people's cooperation with health behavior guidelines. This highlights that the pandemic is not only an issue to be tackled with the tools of immunology and epidemiology. It also requires the tools from psychology-to measure the representations people have about themselves and others and how these representations drive values and decisions related to health. Here we report work on U.S. respondents that examined whether individuals' level of identification with all humanity predicts their prosocial health behaviors aimed at mitigating the spread of COVID-19. In 3 convergent studies (total N = 1,580), we find that identification with all humanity predicted the prosocial motivation to wear masks and to engage in physical distancing when in public without a mask. The results were obtained while controlling for a host of covariates, including demographics, educational attainment, and Big Five personality dimensions. We find that some people have a marked drive to care for the health of strangers, which is significantly linked to their concern for all humanity rather than being restricted to their care for their community or country. Discussion focuses on this social identification with humanity and its enduring, replicable role in predicting the motivation to engage in prosocial health behaviors. We note key implications for theories in social and developmental psychology as well as for research that may lead to practical applications for lessening the human toll of the current and future pandemics.

Contributions of Emotion Regulation and Brain Structure and Function to Adolescent Internalizing Problems and Stress Vulnerability During the COVID-19 Pandemic: A Longitudinal Study.

BACKGROUND: Adolescence is a period of increased vulnerability for internalizing problems, particularly following stressful life events. We examined how emotion regulation and brain structure and function were associated with internalizing problems during the COVID-19 pandemic and moderated the association between pandemic-related stressors and internalizing problems. METHODS: Data are from a longitudinal sample (N = 145, age range, 10-15 years) strategically assessed at 3 crucial time points: before the COVID-19 pandemic, early during the stay-at-home order period, and again 6 months later. We examined associations of amygdala and hippocampal volume and amygdala activation during an emotional processing task before the pandemic, examined use of emotion regulation strategies before and during the pandemic, and examined pandemic-related stressors with internalizing problems. RESULTS: Greater exposure to pandemic-related stressors was associated with higher internalizing problems both early and later in the COVID-19 pandemic. Youths who reported more frequent use of rumination before the pandemic and higher use of expressive suppression and lower use of cognitive reappraisal early in the pandemic had higher internalizing problems early in the pandemic. Higher left amygdala activation to neutral relative to fearful faces before the pandemic was associated with greater internalizing problems and a stronger link between pandemic-related stressors and internalizing problems early in the pandemic. CONCLUSIONS: Stressors related to the COVID-19 pandemic are strongly associated with adolescent internalizing problems, as are individual differences in emotional reactivity and regulation and their underlying neural mechanisms. Interventions that reduce pandemic-related stressors and foster adaptive emotion regulation skills may protect against adolescent psychopathology during this period of heightened exposure to stress.

Gender stereotypes about interests start early and cause gender disparities in computer science and engineering.

Societal stereotypes depict girls as less interested than boys in computer science and engineering. We demonstrate the existence of these stereotypes among children and adolescents from first to 12th grade and their potential negative consequences for girls' subsequent participation in these fields. Studies 1 and 2 (n = 2,277; one preregistered) reveal that children as young as age six (first grade) and adolescents across multiple racial/ethnic and gender intersections (Black, Latinx, Asian, and White girls and boys) endorse stereotypes that girls are less interested than boys in computer science and engineering. The more that individual girls endorse gender-interest stereotypes favoring boys in computer science and engineering, the lower their own interest and sense of belonging in these fields. These gender-interest stereotypes are endorsed even more strongly than gender stereotypes about computer science and engineering abilities. Studies 3 and 4 (n = 172; both preregistered) experimentally demonstrate that 8- to 9-y-old girls are significantly less interested in an activity marked with a gender stereotype ("girls are less interested in this activity than boys") compared to an activity with no such stereotype ("girls and boys are equally interested in this activity"). Taken together, both ecologically valid real-world studies (Studies 1 and 2) and controlled preregistered laboratory experiments (Studies 3 and 4) reveal that stereotypes that girls are less interested than boys in computer science and engineering emerge early and may contribute to gender disparities.

Neural mechanisms underlying the income-achievement gap: The role of the ventral visual stream.

Children from low-socioeconomic status (SES) households on average exhibit lower academic achievement than their higher-SES peers. We investigated a novel hypothesis that differences in early-developing sensory networks-specifically the ventral visual stream (VVS), which is involved in processing visual stimuli-contribute to SES-related disparities in executive functions (EF) and academic outcomes. We used fMRI to investigate SES-related differences in neural function in children (6-8 years, n = 62) during two attentional tasks involving attention to visual information: cued attention and memory-guided attention. Recruitment of VVS during both tasks was associated with EF and academic achievement, and SES-related differences in VVS activation during cued attention were marginally explained by differences in cognitive stimulation. VVS activation during cued attention mediated SES-related differences in academic achievement. Finally, the link between VVS activation during both tasks and academic achievement was mediated by differences in EF. We extend previous work by highlighting that: (i) early-developing visual processing regions play a role in supporting complex attentional processes, (ii) childhood SES is associated with VVS function, which is explained in part by SES-related differences in cognitive stimulation and (iii) provide preliminary evidence that individual differences in VVS function may play a role in the emergence of the income-achievement gap.

Linguistic and developmental influences on superordinate facial configuration categorization in infancy.

Humans perceive emotions in terms of categories, such as "happiness," "sadness," and "anger." To learn these complex conceptual emotion categories, humans must first be able to perceive regularities in expressive behaviors (e.g., facial configurations) across individuals. Recent research suggests that infants spontaneously form "basic-level" categories of facial configurations (e.g., happy vs. fear), but not "superordinate" categories of facial configurations (e.g., positive vs. negative). The current studies further explore how infant age and language impact superordinate categorization of facial configurations associated with different negative emotions. Across all experiments, infants were habituated to one person displaying facial configurations associated with anger and disgust. While 10-month-olds formed a category of person identity (Experiment 1), 14-month-olds formed a category that included negative facial configurations displayed by the same person (Experiment 2). However, neither age formed the hypothesized superordinate category of negative valence. When a verbal label ("toma") was added to each of the habituation events (Experiment 3), 10-month-olds formed a category similar to 14-month-olds in Experiment 2. These findings intersect a larger conversation about the nature and development of children's emotion categories and highlight the importance of considering developmental processes, such as language learning and attentional/memory development, in the design and interpretation of infant categorization studies.

Promoting youth mental health during the COVID-19 pandemic: A longitudinal study.

The COVID-19 pandemic has introduced novel stressors into the lives of youth. Identifying factors that protect against the onset of psychopathology in the face of these stressors is critical. We examine a wide range of factors that may protect youth from developing psychopathology during the pandemic. We assessed pandemic-related stressors, internalizing and externalizing psychopathology, and potential protective factors by combining two longitudinal samples of children and adolescents (N = 224, 7-10 and 13-15 years) assessed prior to the pandemic, during the stay-at-home orders, and six months later. We evaluated how family behaviors during the stay-at-home orders were related to changes in psychopathology during the pandemic, identified factors that moderate the association of pandemic-related stressors with psychopathology, and determined whether associations varied by age. Internalizing and externalizing psychopathology increased substantially during the pandemic. Higher exposure to pandemic-related stressors was associated with increases in internalizing and externalizing symptoms early in the pandemic and six months later. Having a structured routine, less passive screen time, lower exposure to news media about the pandemic, and to a lesser extent more time in nature and getting adequate sleep were associated with reduced psychopathology. The association between pandemic-related stressors and psychopathology was reduced for youths with limited passive screen time and was absent for children, but not adolescents, with lower news media consumption related to the pandemic. We provide insight into simple, practical steps families can take to promote resilience against mental health problems in youth during the COVID-19 pandemic and protect against psychopathology following pandemic-related stressors.

Human infants can override possessive tendencies to share valued items with others.

Possessiveness toward objects and sharing are competing tendencies that influence dyadic and group interactions within the primate lineage. A distinctive form of sharing in adult Homo sapiens involves active giving of high-valued possessions to others, without an immediate reciprocal benefit. In two Experiments with 19-month-old human infants (N = 96), we found that despite measurable possessive behavior toward their own personal objects (favorite toy, bottle), infants spontaneously gave these items to a begging stranger. Moreover, human infants exhibited this behavior across different types of objects that are relevant to theory (personal objects, sweet food, and common objects)-showing flexible generalizability not evidenced in non-human primates. We combined these data with a previous dataset, yielding a large sample of infants (N = 192), and identified sociocultural factors that may calibrate young infants' sharing of objects with others. The current findings show a proclivity that is rare or absent in our closest living relatives-the capacity to override possessive behavior toward personally valued objects by sharing those same desired objects with others.