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Recent theories of socio-moral development assume that humans evolved a capacity to evaluate others' social actions in different kinds of interactions. Prior infant studies found both reaching and visual preferences for the prosocial over the antisocial agents. However, whether the attribution of either positive or negative valence to agents' actions involved in an aggressive chasing interaction can be inferred by both reaching behaviors and visual attention deployment (i.e., disengagement of visual attention) is still an open question. Here we presented 7-month-old infants (N = 92) with events displaying an aggressive chasing interaction. By using preferential reaching and an attentional task (i.e., overlap paradigm), we assessed whether and how infants evaluate aggressive chasing interactions. The results demonstrated that young infants prefer to reach the victim over the aggressor, but neither agent affects visual attention. Moreover, such reaching preferences emerged only when dynamic cues and emotional face-like features were congruent with agents' social roles. Overall, these findings suggested that infants' evaluations of aggressive interactions are based on infants' sensitivity to some kinematic cues that characterized agents' actions and, especially, to the congruency between such motions and the face-like emotional expressions of the agents., (© 2024 Wiley Periodicals LLC.)

Purpose: Controversy exists on the best fixation for total knee arthroplasty (TKA). Non-cemented fixation has been theorized to improve patient outcomes and longevity of implantation but no study has focused on comparison between cemented or cementless posterior-stabilized implants despite being the most commonly or second most frequently utilized implant in most total knee replacement registries., Methods: Inclusion criteria with observational and interventional papers, and review articles that focused on patients with cementless and cemented PS TKAs were used to analyze outcomes such as implant survivorship, complication, or revision rates. Using a combination of keywords, a systematic search was performed on Medline (PubMed), Embase, and Cochrane Library for Meta-Analysis., Results: When using the specified criteria, only 8 studies were selected for full-text analysis and meta-analysis after eliminating screening duplicates, titles, and abstracts without full-text access. These eight studies contain 1652 patients, 693 in the non-cemented Group, and 959 in the cemented total knee prosthesis Group. The meta-analysis revealed the advantage of cementless fixation over cemented fixation in implant survivorship, with 0.6% and 2.6% of aseptic loosening in each Group. The cumulative survival at 12 years was 97.4% for the cementless Group and 89.2% for the cemented Group. The subgroup with a stem showed a positive outcome for cementless fixation over cemented fixation regarding implant survivorship. No differences between the cemented and cementless TKAs were observed in patient-reported outcomes, revision rates, or radiolucent line development., Conclusion: We observed comparable rates for cemented and cementless posterior-stabilized TKAs over a medium-term follow-up period., (© The Authors, published by EDP Sciences, 2024.)

Perceiving facial expressions is an essential ability for infants. Although previous studies indicated that infants could perceive emotion from expressive facial movements, the developmental change of this ability remains largely unknown. To exclusively examine infants' processing of facial movements, we used point-light displays (PLDs) to present emotionally expressive facial movements. Specifically, we used a habituation and visual paired comparison (VPC) paradigm to investigate whether 3-, 6-, and 9-month-olds could discriminate between happy and fear PLDs after being habituated with a happy PLD (happy-habituation condition) or a fear PLD (fear-habituation condition). The 3-month-olds discriminated between the happy and fear PLDs in both the happy- and fear-habituation conditions. The 6- and 9-month-olds showed discrimination only in the happy-habituation condition but not in the fear-habituation condition. These results indicated a developmental change in processing expressive facial movements. Younger infants tended to process low-level motion signals regardless of the depicted emotions, and older infants tended to process expressions, which emerged in familiar facial expressions (e.g., happy). Additional analyses of individual difference and eye movement patterns supported this conclusion. In Experiment 2, we concluded that the findings of Experiment 1 were not due to a spontaneous preference for fear PLDs. Using inverted PLDs, Experiment 3 further suggested that 3-month-olds have already perceived PLDs as face-like stimuli., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Despite its adaptive value for social life, the emergence and the development of the ability to detect agents that cause aversive interactions and distinguish them from potentially affiliative agents (approachers) has not been investigated. We presented infants with a simple interaction involving two agents: one of them (the "repulser") moved toward and pushed the other (the "approacher") which reacted by simply moving toward the repulser without contacting it. We found that 8-month-olds (N = 28) looked longer at the approacher than at the repulser (Experiment 1), whereas 4-month-olds (N = 30) exhibited no preference (Experiment 2). To control for low-level cues (such as the preference for the agent that moved after the contact), two new groups of 4- and 8-month-old infants were presented with a series of interactions in which the agents inverted their social roles. Older infants (N = 30) manifested no preference for either agent (Experiment 3), while younger infants (N = 30) looked longer at the first agent to move (Experiment 4). Our results indicated that 8-month-olds' preferences for the approacher over the repulser depended on social information and were finely tuned to agents that display prosocial rather than antisocial behavior. We discuss these findings in light of the development and adaptive value of the ability to negatively evaluate repulsers, to avoid choosing them as partners., (© 2022 Wiley Periodicals LLC.)

Recent research revealed that infants attend to agents' intentions when they evaluate helping actions. The current study investigated whether infants also consider agents' intentions when they evaluate distributive actions. In Experiment 1, 9-month-old infants were first shown two failed attempts to perform a distribution. In the "failed equal distribution," the distributor first tried to reach one of the recipients to deliver an apple, failed, and then attempted to reach the other possible recipient to deliver a different apple and also failed. In the "failed unequal distribution," a different distributor always tried unsuccessfully to reach the same beneficiary. Then, in the test phase, infants were presented with the two distributors side by side, and infants' spontaneous preferential looking and reaching actions were recorded. We found a reliable preference for the equal distributor in both the visual and manual responses. Experiments 2 and 3 helped to rule out alternative explanations based on perceptual cues and affiliative biases. Overall, these findings suggest that infants' ability to evaluate distributive actions relies not only on the outcomes but also on the distributors' intentions., (Copyright © 2022 Elsevier Inc. All rights reserved.)