Tactile training facilitates infants' ability to reach to targets on the body.

This longitudinal study investigated the effect of experience with tactile stimulation on infants' ability to reach to targets on the body, an important adaptive skill. Infants were provided weekly tactile stimulation on eight body locations from 4 to 8 months of age (N = 11), comparing their ability to reach to the body to infants in a control group who did not receive stimulation (N = 10). Infants who received stimulation were more likely to successfully reach targets on the body than controls by 7 months of age. These findings indicate that tactile stimulation facilitates the development of reaching to the body by allowing infants to explore the sensorimotor correlations emerging from the stimulation.

The Human Face Becomes Mapped as a Sensorimotor Reaching Space During the First Year.

Although recent behavioral and neural research indicates that infants represent the body's structure, how they engage self-representations for action is little understood. This study addressed how the human face becomes a reaching space. Infants (N = 24; 2-11 months) were tested longitudinally approximately every 3 weeks on their ability to reach to a vibrating target placed at different locations on the face. Successful reaches required coordinating skin- and body-based codes for location, a problem known as tactile remapping. Findings suggest that a functional representation of the face is initially fragmented. Infants localized targets in the perioral region before other areas (ears/temples). Additionally, infants predominantly reached ipsilaterally to targets. Collectively, the findings illuminate how the face becomes an integrated sensorimotor space for self-reaching.

Missing in action: Tool use is action based.

In this commentary on Osiurak and Reynaud's target article, we argue that action is largely missing in their account of the ascendance of human technological culture. We propose that an action-based developmental account can help to bridge the cognitive-sociocultural divide in explanations of the discovery, production, and cultural transmission of human tool use.

Reaching to the Self: The Development of Infants' Ability to Localize Targets on the Body.

This study focused on the development of infants' sensorimotor knowledge about the layout of their bodies. Little is known about the development of the body as a reaching space, despite the importance of this skill for many self-directed adaptive behaviors, such as removing foreign stimuli from the skin or scratching an itch. A new method was developed in which vibrating targets were placed on the heads and arms of 7- to 21-month-old infants (N = 78) to test reaching localization of targets. Manual localization improved with age, and visual localization was associated with successful reaching. Use of the ipsilateral or contralateral hand varied with body region: Infants primarily used the ipsilateral hand for head targets but the contralateral hand for arm targets, for which ipsilateral reaches were not biomechanically possible. The results of this research highlight a previously understudied form of self-knowledge involving a functional capacity to reach to tactile targets on the body surface.

How beginning handwriting is influenced by letter knowledge: Visual-motor coordination during children's form copying.

Even with recent technological advances, handwriting remains the developmental foundation from which communication via written language unfolds. Despite the importance of handwriting to academic success, previous research with beginning school-age children has only indirectly measured the processes of handwriting using post hoc assessments of legibility and accuracy. We adapted new head-mounted eye-tracking methods to directly measure visual-motor coordination of preschool and early elementary school children (N = 40) as they copied familiar (English letters) and unfamiliar (Cyrillic symbols) letter-like forms in real time. Results indicated that younger children needed more time to visually process a letter or symbol and initiate a writing action compared with older children despite children of all ages writing letters in a similar amount of time. Analyses also revealed that children copied familiar English letters more efficiently than they copied unfamiliar Cyrillic symbols: They spent more time on and made more visual fixations to the Cyrillic symbols compared with the English letters during the copying task. Finally, children made more visual fixations to less frequently occurring English letters than to more frequently occurring ones. Results are considered in relation to how letter recognition influences the development of automaticity in early handwriting.

Culture Influences Action Understanding in Infancy: Prediction of Actions Performed With Chopsticks and Spoons in Chinese and Swedish Infants.

The cultural specificity of action prediction was assessed in 8-month-old Chinese and Swedish infants. Infants were presented with an actor eating with a spoon or chopsticks. Predictive goal-directed gaze shifts were examined using eye tracking. The results demonstrate that Chinese infants only predict the goal of eating actions performed with chopsticks, whereas Swedish infants exclusively predict the goal of eating actions performed with a spoon. Infants in neither culture predicted the goal of object manipulation actions (e.g., picking up food) performed with a spoon or chopsticks. The results support the view that multiple processes (both visual/cultural learning and motor-based direct matching processes) facilitate goal prediction during observation of other peoples' actions early in infancy.

When does tool use become distinctively human? Hammering in young children.

This study examines the development of hammering within an ontogenetic and evolutionary framework using motion-capture technology. Twenty-four right-handed toddlers (19-35 months) wore reflective markers while hammering a peg into a peg-board. The study focuses on the motor characteristics that make tool use uniquely human: wrist involvement, lateralization, and handle use. Older children showed more distally controlled movements, characterized by relatively more reliance on the wrist, but only when hammering with their right hand. Greater age, use of the right hand, and more wrist involvement were associated with higher accuracy; handle use did not systematically change with age. Collectively, the results provide new insights about the emergence of hammering in young children and when hammering begins to manifest distinctively human characteristics.

Tactile localization promotes infant self-recognition in the mirror-mark test.

Mirror self-recognition has been hailed by many as a milestone in the acquisition of self-awareness with respect to phylogenesis and human ontogenesis.1,2,3,4,5,6 Yet there has been considerable controversy over the extent to which species other than humans and their closest primate relatives are capable of mirror self-recognition, and to the mechanisms that give rise to this ability.1,7 One influential view is that mirror self-recognition in humans and their closest primate relatives is a cognitive advance that is a product of primate evolution, stemming from more recently evolved neural structures and networks that develop through experience-independent mechanisms during ontogenesis.1 In contrast, we show that the development of mirror self-recognition in human infants is a perception-action achievement, building on infants' ability to localize and reach to targets on the body. Infants who were given experience reaching to tactile targets on their bodies in the months prior to recognizing themselves in a mirror achieved mirror self-recognition earlier than infants in either a yoked age-matched control group or a longitudinal control group without such experience. Our results demonstrate that self-touch functions as an intermodal gateway through which infants learn how to localize and reach to stimuli on their bodies, including those that can only be seen in a mirror. These findings identify an overlooked role for the routine activity of self-touch in establishing a representation of the body and suggest that the development of human self-awareness is rooted in self-directed action.

Motor origins of tool use.

The current study examines the developmental trajectory of banging movements and its implications for tool use development. Twenty (6- to 15-month-old) infants wore reflective markers while banging a handled cube; movements were recorded at 240 Hz. Results indicated that through the second half-year, banging movements undergo developmental changes making them ideally suited for instrumental hammering and pounding. Younger infants were inefficient and variable when banging the object: Their hands followed circuitous paths of great lengths at high velocities. By 1 year, infants showed consistent and efficient straight up-down hand trajectories of smaller magnitude and velocity, allowing for precise aiming and delivering dependable levels of force. The findings suggest that tool use develops gradually from infants' existing manual behaviors.

What is the role of infant banging in the development of tool use?

Throughout the first year, infants are known to engage in repetitive motor behaviors. The current study examines the changes in the hand trajectory of one such behavior, banging, during the second half-year and the implications of these changes for tool use development. Fourteen (7- to 14-month-old) infants were seated at a table and presented with a small wooden cube. Kinematic measurements of their banging movements were recorded at 240 Hz. Analyses revealed stable temporal characteristics of the hand trajectories within and across infants. Results further indicated that as infants became older, their hands moved more efficiently in straighter up-and-down trajectories, with developmental changes especially pronounced for upward excursions of the hand: Younger infants' arm movements were less straight on the way up than down, but there was no difference in the straightness of the two movement phases for older infants. These changes with age may reflect improvements in overcoming constraints associated with gravity and/or in motor planning. Additionally, the angle at which infants hit the table became more perpendicular with age. Collectively, the reported changes lead to more efficient movements, better aim and improved force delivery, enabling spontaneous banging movements to become well suited for instrumental hammering and tool use, more generally, later in childhood.

Young Children's Interactions with Objects: Play as Practice and Practice as Play.

Objects permeate human culture and saturate the imagination. This duality offers both opportunity and challenge. Here we ask how young human children learn to exploit the immense potential afforded by objects that can exist simultaneously in both physical and imaginary realms. To this end, we advance a new framework that integrates the presently siloed literatures on manual skill and play development. We argue that developments in children's real and imagined use of objects are embodied, reciprocal and intertwined. Advances in one plane of action influence and scaffold advances in the other. Consistent with this unified framework, we show how real and imagined interactions with objects are characterized by developmental parallels in how children a) gradually move beyond objects' designed functions, b) extend beyond the self, and c) transcend the present to encompass future points in time and space. As well, we highlight how children's real and imagined interactions with objects are intertwined and reciprocally influence each other throughout development: Play engenders practice and skill in using objects, but just the same, practice using objects engenders advances in play. We close by highlighting the theoretical, empirical and translational implications of this embodied and integrated account of manual skill and play development.

Change in imitation for object manipulation between 10 and 12 months of age.

By the end of the first year, infants show dramatic increases in manual skill. In this study we tested one factor likely to contribute to this change: an increase in the capacity for observational learning, which may enable infants to learn new behaviors and practice ones that they already possess. Thus, we evaluated change in imitation between 10 and 12 months of age. Twelve 10-month-olds and twelve 12-month-old infants were shown different kinds of manual actions on a variety of objects; infants also manipulated objects during a free play control condition. Results indicated that older infants benefited more than younger ones in the Demonstration condition and that at both ages, infants performed the target action more quickly after observing a demonstration. We hypothesize that observational learning can help manual skill development by enabling infants to learn new actions and select and practice ones already in their skill set.

Learning the designed actions of everyday objects.

How do young children learn to use everyday artifacts-doorknobs, zippers, and so on-in the ways they were designed to be used? Although the designed actions of such objects seem obvious to adults, little is known about how young children learn the "hidden affordances" of everyday objects. We encouraged 115 11- to 37-month-old children to open 2 types of containers: circular jars with twist-off lids (Experiment 1) and rectangular Tupperware-style containers with pull-off lids (Experiment 2). We varied container size to examine effects of the body-environment fit on display of the designed action and successful implementation of the designed action. Results showed a developmental progression from nondesigned actions to performance of the designed twisting or pulling actions to successful implementation of the designed action. Nondesigned actions decreased with age as performance of the designed action increased. Successful implementation lagged behind performance of the designed action. That is, even after children appeared to know what to do, they were still unsuccessful in opening the container. Why? For twist-offs, very large lids were difficult to manipulate, and younger children often twisted to the right, or in both directions, and did not persist in consecutive turns to the left. Larger pull-off containers required new strategies to stabilize the base, such as holding the container against the tabletop or the chest. Findings provide insights into the body-environment factors that facilitate children's learning and implementation of the hidden affordances inherent in everyday artifacts. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Development of Infant Reaching Strategies to Tactile Targets on the Face.

Infant development of reaching to tactile targets on the skin has been studied little, despite its daily use during adaptive behaviors such as removing foreign stimuli or scratching an itch. We longitudinally examined the development of infant reaching strategies (from just under 2 to 11 months) approximately every other week with a vibrotactile stimulus applied to eight different locations on the face (left/right/center temple, left/right ear, left/right mouth corners, and chin). Successful reaching for the stimulus uses tactile input and proprioception to localize the target and move the hand to it. We studied the developmental progression of reaching and grasping strategies. As infants became older the likelihood of using the hand to reach to the target - versus touching the target with another body part or surface such as the upper arm or chair - increased. For trials where infants reached to the target with the hand, infants also refined their hand postures with age. As infants became older, they made fewer contacts with a closed fist or the dorsal part of the hand and more touches/grasps with the fingers or palm. Results suggest that during the first year infants become able to act more precisely on tactile targets on the face.

An Eye-Tracking Method for Directly Assessing Children's Visual-Motor Integration.

BACKGROUND: Visual-motor integration is an integral component of many adaptive behaviors and has been linked to school readiness. In young school-age children, visual-motor integration is typically assessed with the Beery-Buktenica Developmental Test of Visual Motor Integration (Beery VMI), a standardized instrument that measures children's ability to copy 2-dimensional forms. The Beery VMI is scored according to children's final written product, but does not directly measure the process of visual-motor integration that underlies children's form copying. OBJECTIVE: We describe a new way of directly assessing visual-motor integration in real time. We demonstrate how head-mounted eye-tracking technology for young children can be used to describe the dynamics of visual-motor integration when children copy forms. DESIGN: This study used a cross-sectional design. METHODS: Typically developing kindergarten children (N = 20) were tested as they wore an eye-tracker while performing the Beery VMI. RESULTS: Participants' success (b = -0.66; SE = 0.08; Cohen f2 = 1.11) and their efficiency in visual (b = 0.29; SE = 0.02; Cohen f2 = 0.55) and motor (b = 0.12; SE = 0.01; Cohen f2 = 0.90) processes during form copying decreased as the stimulus complexity increased. LIMITATIONS: A small convenience sample was used to determine proof of concept. A larger, more representative sample is necessary to provide generalizable results. CONCLUSIONS: The new methods used here offer the possibility of more fine-grained assessments of eye-hand coordination in typically developing children and children with such clinical conditions as dysgraphia and developmental coordination disorder.

The Development of Object Fitting: The Dynamics of Spatial Coordination.

Fitting objects into apertures is an adaptive skill that is incorporated into the design of many tools. We match or align shapes with openings when we insert keys into locks, when we put lids atop containers, or when we align a screwdriver with the groove of a screw. Traditionally, the development of object fitting has focused on children's abilities to successfully complete shape sorter tasks (e.g., square peg through square hole). By measuring children's success in these tasks, investigators have determined that there is substantial development during the second year, but little research has addressed the processes children employ to solve object fitting challenges during this time period. Here, we provide a process based account of object fitting, which emphasizes how children coordinate information about spatial structure with action. We suggest that a process-based approach can illuminate the real-time dynamics of perceiving, acting, and thinking.

Fitting handled objects into apertures by 17- to 36-month-old children: The dynamics of spatial coordination.

Handled artifacts are ubiquitous in human technology, but how young children engage in spatially coordinated behaviors with these artifacts is not well understood. To address this issue, children (N = 30) from 17-36 months were studied with motion tracking technology as they fit the distal segment of a handled artifact into a slot. The handle was orthogonal to the distal segment. Results revealed developmental differences in prospective control tied to the artifact's spatial structure. Although all children accomplished fitting, younger children first oriented the handle and then the distal segment (and only after the distal segment contacted the slot), whereas children by 3 years of age oriented the handle and distal segment simultaneously in different spatial planes, prior to the distal segment contacting the slot. Choosing an effective grip posture proved difficult for all children. Results are discussed in terms of how children begin to relate their actions to the 3-dimensional spatial structure of handled objects and the prospective control of object movement in multiple spatial planes. (PsycINFO Database Record