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How infants engage with objects changes dramatically over the first year of life. While some infants exhibit a consistent hand preference for acquiring objects during this period, others have no identifiable preference. The goal of this study was to test whether lateralization confers an advantage in the development of early object management skills. We examined whether lateralized infants show different rates of growth in how they interact with multiple objects as compared to infants without a hand preference. In a longitudinal study consisting of seven monthly visits from 6 to 12 months, 303 infants were assessed for their hand preference and object management skill (i.e., holding up to three objects). Group-Based Trajectory Modeling (GBTM) identified the following three hand preference trajectory groups: Left, Right, and No Preference (NP). A Hierarchical Generalized Linear Model (HGLM) with the NP infants as the reference group for statistical comparisons revealed that while all the infants showed similar trends in their object management skills over time, the lateralized infants had an advantage over the non-lateralized infants. The infants in the Right and Left groups transitioned from holding one to two objects more quickly relative to the NP infants. Further research is needed to determine if this early object skill advantage cascades to a more complex handling of multiple objects. [ABSTRACT FROM AUTHOR]

Background: Parents' conceptualizations of adulthood for their emerging adults with Down syndrome have the potential to impact the transition planning process as families prepare for life after graduation. Aims: This study aimed to explore parent perceptions of the meaning of adulthood for their emerging adults with Down syndrome. Methods: In this qualitative study, we interviewed 11 parents of emerging adults with Down syndrome using phenomenological methodology and analysed these data using thematic analysis. Results: Three topics emerged: (1) Parents' constructions of the meaning of adulthood; (2) Parents' perceptions about the transition to adulthood; and (3) Parents' perceptions of current adult life skills. Ten themes arose out of these topics. Conclusions: Parents expressed ambivalence about the meaning of adulthood for their emerging adults with Down syndrome, sharing that in some ways they were adults and in others they were not. The meaning of adulthood was closely tied to obtained skills, particularly those related to personal safety. [ABSTRACT FROM AUTHOR]

Prior studies found that hand preference trajectories predict preschool language outcomes. However, this approach has been limited to examining bimanual manipulation in toddlers. It is not known whether hand preference during infancy for acquiring objects (i.e., reach‐to‐grasp) similarly predicts childhood language ability. The current study explored this motor‐language developmental cascade in 90 children. Hand preference for acquiring objects was assessed monthly from 6 to 14 months, and language skill was assessed at 5 years. Latent class growth analysis identified three infant hand preference classes: left, early right and late right. Infant hand preference classes predicted 5‐year language skills. Children in the left and early right classes, who were categorized as having a consistent hand preference, had higher expressive and receptive language scores relative to children in the inconsistent late right class. Consistent classes did not differ from each other on language outcomes. Infant hand preference patterns explained more variance for expressive and receptive language relative to previously reported toddler hand preference patterns, above and beyond socio‐economic status. Results suggest that hand preference, measured at different time points across development using a trajectory approach, is reliably linked to later language. Highlights: Hand preference trajectories reliably predict preschool language above and beyond SES.Infants with a consistent hand preference for reaching had greater language skills at 5 years.Infant hand preference explained more variance in language than toddler hand preference. [ABSTRACT FROM AUTHOR]

A defining feature of most primates is a hand with five fingers. Spider monkeys are an exception because they have four fingers and no thumb. Despite the prevalence of reach-to-grasp research in primates, it is not known how the lack of a thumb affects reaching and grasping in spider monkeys. Drawing on patterns that have been well described in human adults, human infants, and other nonhuman primates, this study characterized prehension in Colombian spider monkeys (Ateles fusciceps rufiventris). Monkeys reached for two differently sized food objects and reaches were digitized offline for two-dimensional kinematic analysis. Grasp strategy was coded from video as preshaped when the hand was adjusted to grasp the food before contact, or not preshaped when the hand was adjusted to grasp the food after contact. Monkeys exhibited variability in reach smoothness that contrasted with the typical pattern seen in other adult primates and instead resembled the pattern observed in human infants. Monkeys anticipated the object to be grasped approximately half of the time. Reaches where the hand was preshaped to the object were smoother than reaches where the hand was adjusted to grasp after object contact. For the small object, reaches with preshaping were straighter than reaches without preshaping. Results are the first evidence of kinematic signatures for reach-to-grasp actions in spider monkeys. [ABSTRACT FROM AUTHOR]

I argue that the future of comparative cognition is not what we study but how we study it. I suggest that future scientists should ask questions from a developmental framework. I review common challenges in longitudinal research that scientists in comparative cognition encounter. Leveraging emerging large-scale collaborations within and across taxa (i.e., big team science) can enable us to overcome these challenges to answer how cognitive abilities develop. This appeal for a developmental lens will facilitate interdisciplinary discussion in comparative cognition. [ABSTRACT FROM AUTHOR]

Unlike in human research, infants are poorly represented in the literature on nonhuman primate laterality. Studies have traditionally measured adults, a trend captured by prior reviews. The extent of the knowledge gaps related to laterality measured early in the lifespan is unknown. As a starting point, this systematic review examined the evidence on behavioral laterality across the first year of life in nonhuman primates using the PRISMA guidelines. The inclusion criteria were at least one measure of behavioral laterality in at least one subject < 1 year old. Database searches were conducted in PsycINFO, PubMed, and OVID Medline using the filterNHP search builder tool, and additional records were identified through citation searching. Two independent reviewers screened abstracts and full texts; 47 articles were retained (0 prosimian, 6 platyrrhine, 27 catarrhine, and 14 ape studies). Macaca and Pan were overrepresented. Nipple preference was the most-studied behavior, followed by hand preference. Modifying how data are collected and analyzed will increase developmental rigor in primate studies. To facilitate comparisons with the human infant literature, we suggest measuring a behavior more than once to test for change or continuity in preference over time and measuring different behaviors at different timepoints to test for potential developmental cascades. [ABSTRACT FROM AUTHOR]