Infant Placement and Language Exposure in Daily Life.

Children's daily contexts shape their experiences. In this study we assessed whether variations in infant placement (e.g., held, bouncy seat) are associated with infants' exposure to adult speech. Using repeated survey sampling of mothers and continuous audio recordings, we tested whether use of independence-supporting placements was associated with adult speech exposure in a Southeastern U.S. sample of 60 4- to 6- month- old infants (38% male, predominately White, not Hispanic/Latinx, from higher SES households). Within-subject analyses indicated that independence-supporting placements were associated with exposure to fewer adult words in the moment. Between-subjects analyses indicated that infants more frequently reported to be in independence-supporting placements that also provided posture support (i.e., exersaucer) were exposed to fewer adult words and less consistent adult speech across the day. These findings indicate that infants' opportunities for exposure to adult speech "in the wild" may vary based on immediate physical context.

Kinematic and Somatosensory Gains in Infants with Cerebral Palsy After a Multi-Component Upper-Extremity Intervention: A Randomized Controlled Trial.

Upper extremity (UE) impairments in infants with cerebral palsy (CP) result from reduced quality of motor experiences and "noisy" sensory inputs. We hypothesized that a neuroscience-based multi-component intervention would improve somatosensory processing and motor measures of more-affected (UEs) in infants with CP and asymmetric UE neurologic impairments, while remaining safe for less-affected UEs. Our randomized controlled trial compared infants (6-24 months) with CP receiving intervention (N = 37) versus a waitlisted group (N = 36). Treatment effects tested a direct measurement of reach smoothness (3D-kinematics), a measure of unimanual fine motor function (Bayley unimanual fine motor raw scores), and EEG measures of cortical somatosensory processing. The four-week therapist-directed, parent-administered intervention included daily (1) bimanual play; (2) less-affected UE wearing soft-constraint (6 h/day, electronically-monitored); (3) reach training on more-affected UE; (4) graduated motor-sensory training; and (5) parent education. Waitlist infants received only bimanual play. Effectiveness and safety were tested; z-scores from 54 posttest-matched typically-developing infants provided benchmarks for treatment effects. Intervention and waitlist infants had no pretest differences. Median weekly constraint wear was 38 h; parent-treatment fidelity averaged > 92%. On the more affected side, the intervention significantly increased smoothness of reach (Cohen's d = - 0.90; p < .001) and unimanual fine motor skill (d = 0.35; p = .004). Using unadjusted p values, intervention improved somatosensory processing (d = 0.53; p = .04). All intervention effects referenced well to typically developing children. Safety of the intervention was demonstrated through positive- or non-effects on measurements involving the constrained, less-affected UE and gross motor function; unexpected treatment effects on reach smoothness occurred in less-affected UEs (d = - 0.85; p = .01). This large clinical trial demonstrated intervention effectiveness and safety for developing sensory and motor systems with improvements in reach smoothness, and developmental abilities.Clinical Trail Registration: ClinicalTrials.gov NCT02567630, registered October 5, 2015.

Twelve-Month-Old Infants Respond to Speech About Absent Inaccessible Objects.

This article investigated the interplay of 12-month-old infants' perception of affordances for locomotion and their ability to respond to the mention of hidden objects. In Experiment I, a toy was hidden in an ottoman that was placed on a cabinet out of infants' reach. Infants were more likely to look at, point to or approach the ottoman when there were stairs leading to it than when there were none. The stairs did not help infants respond by highlighting the target corner of the room (Experiment II) or by boosting their engagement with the study events (Experiment III). This suggests that infants' perception of the accessibility of the hiding location influences their ability to respond to speech about absent things.

Characteristics of brief sticky mittens training that lead to increases in object exploration.

The onset of independent prehension marks the beginning of infants' direct interaction with the physical world. The success infants have in contacting objects with their hands and arms can have both visual and auditory consequences; objects may move and collide with other objects or fall onto table surfaces. Seeing and hearing these events could have important consequences for infants' learning about objects and their subsequent behavior toward objects. The current research assessed the effects of brief object manipulation experiences and how a specific characteristic of training, auditory feedback produced by hard plastic toys colliding with a tabletop surface, affects pre-reaching infants' subsequent object exploration. In Experiment 1, infants participated in either active "sticky" mittens training or passive "nonsticky" mittens training with a set of toys; before and after this experience, infants explored a teether. Results showed that infants participating in active training increased looking toward and sustained touching of the teether from pre- to post-training, whereas infants receiving passive training decreased their looking toward and touching of the teether following training. To investigate whether infants' exploration behaviors were related to the amount of auditory feedback produced by the objects during training, in Experiment 2 data were collected from infants who received active sticky mittens training that had either more or less auditory feedback potential. Results showed more robust increases in infants' exploratory activity from pre- to post-training in the more auditory feedback condition compared with infants' exploratory activity in the less auditory feedback condition. These findings support the idea that active control of objects, including experiencing contingent feedback through multiple sensory modalities, promotes the development of object exploration during early infancy.

Motor training at 3 months affects object exploration 12 months later.

The development of new motor skills alters how infants interact with objects and people. Consequently, it has been suggested that motor skills may initiate a cascade of events influencing subsequent development. However, only correlational evidence for this assumption has been obtained thus far. The current study addressed this question experimentally by systematically varying reaching experiences in 40 three-month-old infants who were not reaching on their own yet and examining their object engagement in a longitudinal follow-up assessment 12 months later. Results revealed increased object exploration and attention focusing skills in 15-month-old infants who experienced active reaching at 3 months of age compared to untrained infants or infants who only passively experienced reaching. Further, grasping activity after - but not before - reaching training predicted infants' object exploration 12 months later. These findings provide evidence for the long-term effects of reaching experiences and illustrate the cascading effects initiated by early motor skills.

Infants' observation of tool-use events over the first year of life.

How infants observe a goal-directed instrumental action provides a unique window into their understanding of others' behavior. In this study, we investigated eye-gaze patterns while infants observed events in which an actor used a tool on an object. Comparisons among 4-, 7-, 10-, and 12-month-old infants and adults reveal changes in infants' looking patterns with age; following an initial face bias, infants' scan path eventually shows a dynamic integration of both the actor's face and the objects on which they act. This shift may mark a transition in infants' understanding of the critical components of tool-use events and their understanding of others' behavior.

How babies use their hands to learn about objects: Exploration, reach-to-grasp, manipulation, and tool use.

Object play is essential for infant learning, and infants spend most of their day with objects. Young infants learn about objects and their properties through multimodal exploration facilitated by caregivers. They figure out how to transport their hands to where objects are, and how to grasp objects in increasingly complex ways. Building on earlier experiences, they learn how to use their hands collaboratively to act on objects, and how to use objects to act on other objects in instrumental ways. These changes in how infants use their hands occur during the most rapid period of motor development and may have important downstream implications for other domains. Recent research findings have established the importance of effective fine motor skills for later academic skills, yet our understanding of the factors that influence the early development of hand skills is sparse at best. Latest research on reaching, grasping, object manipulation, hands collaboration, and tool use is reviewed and connections among these developments are explained from the perspective of developmental cascades. This article is categorized under: Psychology > Motor Skill and Performance Psychology > Development and Aging.

Infants exploring objects: A cascades perspective.

Infants spend much of their time exploring objects (Herzberg et al., 2021), and object exploration is linked to learning and development in various domains (e.g., social, cognitive, motor). But how does exploration develop in the first place, and how, exactly, does exploration promote learning? One way to approach these process-oriented questions is with a developmental cascades perspective, which holds that new skills emerge from earlier-developing ones and that various interactions with people and objects accumulate over time to influence multiple domains of development (Masten & Cicchetti, 2010). In this chapter, we describe object exploration from a developmental cascades perspective. In Section 2, we describe typical and atypical trajectories of exploration behaviors, noting how these behaviors emerge from earlier-developing cognitive and motor skills. In Section 3, we discuss how object exploration opens the door for new types of learning opportunities. In Section 4, we discuss early experiences that may shape the development of object exploration. Altogether, we aim to convey that new developments in exploration skills are extensions of earlier-developing skills, and that seemingly insignificant exploratory behaviors (e.g., shaking a rattle) may result in numerous and varied consequences for the developing infant.

Case report: An evaluation of early motor skills in an infant later diagnosed with autism.

Researchers and clinicians are increasingly interested in understanding the etiology of autism spectrum disorder (ASD) and identifying behaviors that can provide opportunities for earlier detection and therefore earlier onset of intervention activities. One promising avenue of research lies in the early development of motor skills. The present study compares the motor and object exploration behaviors of an infant later diagnosed with ASD (T.I.) with the same skills in a control infant (C.I.). There were notable difference in fine motor skills by just 3 months of age, one of the earliest fine motor differences reported in the literature. In line with previous findings, T.I. and C.I. demonstrated different patterns of visual attention as early as 2.5 months of age. At later visits to the lab, T.I. engaged in unique problem-solving behaviors not demonstrated by the experimenter (i.e., emulation). Overall, findings suggest that infants later diagnosed with ASD may show differences in fine motor skills and visual attention to objects from the first months of life.

Reaching experience increases face preference in 3-month-old infants.

The developing infant learns about the physical and the social world by engaging with objects and with people. In the study reported here, we investigated the relationship between infants' interactions with the physical and the social world. Three-month-old infants were trained for 2 weeks and experienced either actively manipulating objects themselves or passively having objects touched to their hands. Following active or passive experiences, spontaneous orienting towards faces and objects was compared between the trained groups and untrained 3- and 5-month-olds. It is known that the onset of reaching behavior increases infants' interest in objects. However, we report that active, self-produced reaching experiences also increase infants' spontaneous orienting towards faces, while passive experiences do not affect orienting behavior. Regression analyses provide evidence for a link between manual engagement and the development of orienting towards faces. Implications of orienting towards faces for the development of triadic interactions, joint attention, and social cognition in general are discussed.

Spatial expectations of young human infants, following passive movement.

Three experiments are described that investigate 4.5-month-old infants' spatial thinking during passive movement using a task that required no manual or visual search. In these experiments, infants habituated to a display located near one corner of a table. Before the test trial the infants were either moved to the opposite side of the table or they remained in the same position that they held during the habituation trials. Also, between the habituation trials and the test trial, the display was either surreptitiously moved to the diagonally opposite position on the table, or the display remained stationary. The results showed that infants generally dishabituated when the actual (allocentric/objective) location of the display was changed between habituation and test. However, in Experiment 3, in which infants had reduced experience moving around the testing chamber, infants dishabituated to a change in their egocentric spatial relationship to the display. The results of this experiment suggest that experience moving around the testing chamber was a prerequisite for such location constancy. Taken together, the findings presented here indicate that with enough experience, young infants become aware of key spatial relationships in their environment during passive movement.

Exploratory behavior and developmental skill acquisition in infants with Down syndrome.

Infants learn about objects by exploring them. Typically developing infants actively explore objects through visual, manual, and oral modalities. Attenuated exploratory behavior has been observed in various neurodevelopmental disorders, including Down syndrome (DS), presumably limiting learning options. However, a direct link between exploration and overall developmental functioning has not been characterized. This study used a Latent Profile Analysis framework to examine within-syndrome variability in exploratory behavior in infants with DS and the developmental correlates of different exploratory behavior profiles. Participants were 45 infants with DS (CA = 9.58 months; SD = 3.62) who completed an object exploration activity and the Bayley Scales of Infant Development-III (BSID-III; Bayley, 2006). Exploration behavior was coded for the percentage of time engaged in visual, manual, and oral exploration. Results indicated that a 2-profile solution provided the best model fit for exploratory behavior, yielding profiles that represented either an Active (57.78% of the sample) or a Passive Exploratory (42.22% of the sample) profile. The Active Exploratory profile was associated with significantly higher age equivalent scores on the BSID-III Cognitive, Communication, and Motor domains than the Passive Exploratory profile. Other factors, such as sex and biomedical risk factors, were not associated with exploratory profiles. These findings offer a more nuanced understanding of early within-syndrome heterogeneity in DS, and demonstrate that impoverished early exploratory behavior may serve as an important indicator of increased risk for more pronounced developmental delays in DS.

Developmental differences in infants' use of an object's shape to grasp it securely.

This study examined twenty two 11- and 13-month-old infants' approach and grasp of two objects-one symmetric and one asymmetric-in an effort to understand infants' use of shape information to plan motor action. At first contact, all infants grasped the asymmetrical object further from its center of mass than the symmetrical object. In addition, results highlighted developmental differences in infants' abilities to correct for less stable hand placements, to maintain control of the objects without dropping, strategies used to obtain the objects, and latencies to grasp the objects. Older infants showed more effective skills in each of the aforementioned areas. Implications for our understanding of the development of processing of visual information for action are discussed.

Learning about tools in infancy.

These experiments explored the role of prior experience in 12- to 18-month-old infants' tool-directed actions. In Experiment 1, infants' use of a familiar tool (spoon) to accomplish a novel task (turning on lights inside a box) was examined. Infants tended to grasp the spoon by its handle even when doing so made solving the task impossible (the bowl did not fit through the hole in the box, but the handle did) and even though the experimenter demonstrated a bowl-grasp. In contrast, infants used a novel tool flexibly and grasped both sides equally often. In Experiment 2, infants received training using the novel tool for a particular function; 3 groups of infants were trained to use the tool differently. Later, infants' performance was facilitated on tasks that required infants to grasp the part of the tool they were trained to grasp. The results suggest that (a) infants' prior experiences with tools are important to understanding subsequent tool use, and (b) rather than learning about tool function (e.g., hammering), infants learn about which part of the tool is meant to be held, at least early in their exposure to a novel tool.

Active Motor Training Has Long-term Effects on Infants' Object Exploration.

Long-term changes in infants' behavior as a result of active motor training were studied. Thirty-two infants completed three visits to the laboratory. At the first visit, infants were 3 months old and completed an object exploration assessment. Then the experimenter demonstrated the motor training procedures appropriate for the infant's experimental condition, and parents took home custom infant mittens (either sticky or non-sticky) and a bag of lightweight toys to practice with their infants. Over the course of the following 2 weeks, infants participated in 10 sessions of either active (sticky) or passive (non-sticky) mittens training at home with their parents. Infants who participated in active mittens training wore mittens with the palms covered in Velcro, allowing them to pick up and move around small toys. Infants who participated in passive mittens training wore non-sticky mittens, and their parents moved the toys through their visual fields on their behalf. After completing the training, infants returned to the lab for the second visit. At visit two, infants participated in another object exploration assessment as well as a reaching assessment. Parents returned the training materials to the lab at the second visit, and were told not to continue any specific training regimen from this point forward. Two months later, when infants were about 5.5 months of age, they returned to the lab for a third visit. At the third visit, infants completed the same two assessments as during the second visit. The results of this study indicate that infants who participated in active motor training engaged in more sophisticated object exploration when compared to infants who received passive training. These findings are consistent with others in the literature showing that active motor training at 3 months of age facilitates the processes of object exploration and engagement. The current results and others reveal that the effects of early experience can last long after training ceases.

Infants' formation and use of categories to segregate objects.

Four- and-a-half-month-old infants' (N = 100) category formation and use was studied in a series of five experiments. For each experiment, the test events featured a display composed of a cylinder and a box. Previous research showed that this display is not clearly parsed as a single unit or as two separate units by infants of this age. Immediately prior to testing, infants were shown a set of category exemplars. Knowledge about this category could help infants disambiguate the test display, which contained a novel exemplar of this category. Clear interpretation of the test display as composed of two separate units (as indicated by infants' longer looking at the move-together than at the move-apart test event) was taken as evidence of category formation and use. In Experiments 1 and 5, infants' prior experience with a set of three different boxes that were similar to the test box facilitated their segregation of the test display. Experiment 2 showed that three different exemplars are necessary: prior experience with any two of the three boxes used in Experiment 1 did not facilitate infants' segregation of the test display. Experiment 3 showed that variability in the exemplar set is necessary: prior experience with three identical boxes did not facilitate infants' segregation of the test display. Experiment 4 showed that under these conditions of very brief prior exposure, similarity between the exemplar set and test box is necessary: prior experience with three different boxes that were not very similar to the test box did not facilitate infants' segregation of the test display. Together, these findings suggest that: (a) number of exemplars, variability, and similarity in the exemplar set are important for infants' category formation, and (b) infants use their category knowledge to determine the boundaries of the objects in a display.

Action experience alters 3-month-old infants' perception of others' actions.

An intervention facilitated 3-month-old infants' apprehension of objects either prior to (reach first), or after (watch first) viewing another person grasp similar objects in a visual habituation procedure. Action experience facilitated action perception: reach-first infants focused on the relation between the actor and her goal, but watch-first infants did not. Infants' sensitivity to the actor's goal was correlated with their engagement in object-directed contact with the toys. These findings indicate that infants can rapidly form goal-based action representations and suggest a developmental link between infants' goal directed actions and their ability to detect goals in the actions of others.

Sticky mittens, prickly Velcro, and infants' transition into independent reaching: Response to Williams, Corbetta, and Guan (2015).

Williams, Corbetta, and Guan (2015) report findings on the effects of active and passive motor training in three-month-old infants and argue that passive task exposure is sufficient to encourage future reaching behaviors. In this commentary, we relate these new findings to our body of published work using sticky mittens and describe important differences in the materials and procedures used. In particular, Williams et al. (2015) used modified sticky mittens that allowed infants' fingers to make direct contact with prickly Velcro on the toys, and they used a different training procedure that required infants to discover the hidden functionality of the sticky mittens by themselves. We argue that these differences explain the apparent conflicts between our prior work and the results reported by Williams et al. (2015). The Williams study presented infants with a learning context that was quite different from the one infants encountered in our research, and so it is not surprising that infants in their study showed such different patterns of behavior.

Early childhood constraint therapy for sensory/motor impairment in cerebral palsy: a randomised clinical trial protocol.

INTRODUCTION: Cerebral palsy (CP) is the most common physical disability in childhood. It is a disorder resulting from sensory and motor impairments due to perinatal brain injury, with lifetime consequences that range from poor adaptive and social function to communication and emotional disturbances. Infants with CP have a fundamental disadvantage in recovering motor function: they do not receive accurate sensory feedback from their movements, leading to developmental disregard. Constraint-induced movement therapy (CIMT) is one of the few effective neurorehabilitative strategies shown to improve upper extremity motor function in adults and older children with CP, potentially overcoming developmental disregard. METHODS AND ANALYSIS: This study is a randomised controlled trial of children 12-24 months corrected age studying the effectiveness of CIMT combined with motor and sensory-motor interventions. The study population will comprise 72 children with CP and 144 typically developing children for a total of N=216 children. All children with CP, regardless of group allocation will continue with their standard of care occupational and physical therapy throughout the study. The research material collected will be in the form of data from high-density array event-related potential scan, standardised assessment scores and motion analysis scores. ETHICS AND DISSEMINATION: The study protocol was approved by the Institutional Review Board. The findings of the trial will be disseminated through peer-reviewed journals and scientific conferences. TRIAL REGISTRATION NUMBER: NCT02567630.