The capacity to reason about the false beliefs of others is classically considered the benchmark for a fully fledged understanding of the mental lives of others. Although much is known about the developmental origins of our understanding of others’ beliefs, we still know much less about the evolutionary origins of this capacity. Here, we examine whether non-human primates – specifically, rhesus macaques (Macaca mulatta) – share this developmental achievement. We presented macaques with a looking-time measure of false belief understanding, one that had recently been developed for use with 15-month-old human infants. Like human infants, monkeys look longer when a human experimenter fails to search in the correct location when she has accurate knowledge. In contrast to infants, however, monkeys appear to make no prediction about how a human experimenter will act when she has a false belief. Across three studies, macaques’ pattern of results is consistent with the view that monkeys can represent the knowledge and ignorance of others, but not their beliefs. The capacity to represent beliefs may therefore be a unique hallmark of human cognition.

Self-injurious thoughts and behaviors (SITBs), including nonsuicidal self-injury, suicidal thoughts, suicide attempts, and suicide death exhibit substantial sex differences. Across most countries, men die by suicide more frequently than women; yet, women think about and attempt suicide more frequently than men. Research on sex differences in nonsuicidal self-injury is less developed; however, nonsuicidal self-injury is historically understood as a primarily female phenomenon. This review describes current research on sex differences across SITBs with a focus on factors that moderate these effects, such as age, race, geographic region, and time. Additionally, this review describes factors that may help to explain why sex differences across SITBs exist, including differences in culture, access to lethal suicide methods, rates of mental illness, and utilization of health care. The role of gender, and particularly non-binary gender, is also discussed. Current understanding of these sex differences is described with an eye toward future research on this topic.

Diminished responsivity to reward incentives is a key contributor to the social-communication problems seen in autism spectrum disorders (ASDs). Social motivation theories suggest that individuals with ASD do not experience social interactions as rewarding, leading to negative consequences for the development of brain circuitry subserving social information. In this study, we examined neural responses to social and non-social reward anticipation in 35 typically developing young adults, examining modulation of reward sensitivity by level of autistic traits. Using an Event-related potential incentive-delay task incorporating novel, more ecologically valid forms of reward, higher expression of autistic traits was associated with an attenuated P3 response to the anticipation of social (simulated real-time video feedback from an observer), but not non-social (candy), rewards. Exploratory analyses revealed that this was unrelated to mentalizing ability. The P3 component reflects motivated attention to reward signals, suggesting attenuated motivation allocation specific to social incentives. The study extends prior findings of atypical reward anticipation in ASD, demonstrating that attenuated social reward responsiveness extends to autistic traits in the range of typical functioning. Results support the development of innovative paradigms for investigating social and non-social reward responsiveness. Insight into vulnerabilities in reward processing is critical for understanding social function in ASD.

BackgroundProblems with reward system function have been posited as a primary difficulty in autism spectrum disorders. The current study examined an electrophysiological marker of feedback monitoring, the feedback-related negativity (FRN), during a monetary reward task. The study advanced prior understanding by focusing exclusively on a developmental sample, applying rigorous diagnostic characterization and introducing an experimental paradigm providing more subtly different feedback valence (reward versus non-reward instead of reward versus loss).MethodsTwenty-six children with autism spectrum disorder and 28 typically developing peers matched on age and full-scale IQ played a guessing game resulting in monetary gain (“win”) or neutral outcome (“draw”). ERP components marking early visual processing (N1, P2) and feedback appraisal (FRN) were contrasted between groups in each condition, and their relationships to behavioral measures of social function and dysfunction, social anxiety, and autism symptomatology were explored.ResultsFRN was observed on draw trials relative to win trials. Consistent with prior research, children with ASD exhibited a FRN to suboptimal outcomes that was comparable to typical peers. ERP parameters were unrelated to behavioral measures.ConclusionsResults of the current study indicate typical patterns of feedback monitoring in the context of monetary reward in ASD. The study extends prior findings of normative feedback monitoring to a sample composed exclusively of children and demonstrates that, as in typical development, individuals with autism exhibit a FRN to suboptimal outcomes, irrespective of neutral or negative valence. Results do not support a pervasive problem with reward system function in ASD, instead suggesting any dysfunction lies in more specific domains, such as social perception, or in response to particular feedback-monitoring contexts, such as self-evaluation of one’s errors.

Despite significant social difficulties, children with autism spectrum disorder (ASD) are vulnerable to the effects of social exclusion. We recorded EEG while children with ASD and typical peers played a computerized game involving peer rejection. Children with ASD reported ostracism-related distress comparable to typically developing children. Event-related potentials (ERPs) indicated a distinct pattern of temporal processing of rejection events in children with ASD. While typically developing children showed enhanced response to rejection at a late slow wave indexing emotional arousal and regulation, those with autism showed attenuation at an early component, suggesting reduced engagement of attentional resources in the aversive social context. Results emphasize the importance of studying the time course of social information processing in ASD; they suggest distinct mechanisms subserving similar overt behavior and yield insights relevant to development and implementation of targeted treatment approaches and objective measures of response to treatment.