The development of motor behavior.

This article reviews research on the development of motor behavior from a developmental systems perspective. We focus on infancy when basic action systems are acquired. Posture provides a stable base for locomotion, manual actions, and facial actions. Experience facilitates improvements in motor behavior and infants accumulate immense amounts of experience with all of their basic action systems. At every point in development, perception guides motor behavior by providing feedback about the results of just prior movements and information about what to do next. Reciprocally, the development of motor behavior provides fodder for perception. More generally, motor development brings about new opportunities for acquiring knowledge about the world, and burgeoning motor skills can instigate cascades of developmental changes in perceptual, cognitive, and social domains. WIREs Cogn Sci 2017, 8:e1430. doi: 10.1002/wcs.1430 For further resources related to this article, please visit the WIREs website

Learning to move

ABSTRACT-Locomotion-moving the body from place to place-is one of infants' greatest achievements. In addition to conquering gravity, infants must cope with variable and novel constraints on balance and propulsion. At the same time that they are learning to move, changes in infants' bodies, skills, and environments change the biomechanical constraints on movement. Recent work highlights both flexibility and specificity in infants' responses to novel and variable situations, demonstrating that infants are learning to learn as they master locomotion. Within sitting, crawling, cruising, and walking postures, experienced infants adapt their locomotor responses to the current biomechanical constraints on movement. However, what infants have learned about coping with variability and novelty in earlier-developing postures does not transfer to later-developing postures

Decisions at the Brink: Locomotor Experience Affects Infants’ Use of Social Information on an Adjustable Drop-off

How do infants decide what to do at the brink of a precipice? Infants could use two sources of information to guide their actions: perceptual information generated by their own exploratory activity and social information offered by their caregivers. The current study investigated the role of locomotor experience in using social information—both encouragement and discouragement—for descending drop-offs. Mothers of 30 infants (experienced 12-month-old crawlers, novice 12-month-old walkers, and experienced 18-month-old walkers) encouraged and discouraged descent on a gradation of dropoffs (safe “steps” and risky “cliffs”). Novice walkers descended more frequently than experienced crawlers and walkers and fell while attempting to walk over impossibly high cliffs. All infants showed evidence of integrating perceptual and social information, but locomotor experience affected infants’ use of social messages, especially on risky dropoffs. Experienced crawlers and walkers selectively deferred to social information when perceptual information is ambiguous. In contrast, novice walkers took mothers’ advice inconsistently and only at extreme drop-offs

The ties that bind: Cradling in Tajikistan

A traditional childrearing practice—“gahvora” cradling—in Tajikistan and other parts of Central Asia purportedly restricts movement of infants’ body and limbs. However, the practice has been documented only informally in anecdotal reports. Thus, this study had two research questions: (1) To what extent are infants’ movements restricted in the gahvora? (2) How is time in the gahvora distributed over a 24-hour day in infants from 1–24 months of age? To answer these questions, we video-recorded 146 mothers cradling their infants and interviewed them using 24-hour time diaries to determine the distribution of time infants spent in the gahvora within a day and across age. Infants’ movements were indeed severely restricted. Although mothers showed striking uniformity in how they restricted infants’ movements, they showed large individual differences in amount and distribution of daily use. Machine learning algorithms yielded three patterns of use: day and nighttime cradling, mostly nighttime cradling, and mostly daytime cradling, suggesting multiple functions of the cradling practice. Across age, time in the gahvora decreased, yet 20% of 12- to 24-montholds spent more than 15 hours bound in the gahvora. We discuss the challenges and benefits of cultural research, and how the discovery of new phenomena may defy Western assumptions about childrearing and development. Future work will determine whether the extent and timing of restriction impacts infants’ physical and psychological development

PAPER Developmental continuity? Crawling, cruising, and walking

Abstract This research examined developmental continuity between 'cruising' (moving sideways holding onto furniture for support) and walking. Because cruising and walking involve locomotion in an upright posture, researchers have assumed that cruising is functionally related to walking. Study 1 showed that most infants crawl and cruise concurrently prior to walking, amassing several weeks of experience with both skills. Study 2 showed that cruising infants perceive affordances for locomotion over an adjustable gap in a handrail used for manual support, but despite weeks of cruising experience, cruisers are largely oblivious to the dangers of gaps in the floor beneath their feet. Study 3 replicated the floor-gap findings for infants taking their first independent walking steps, and showed that new walkers also misperceive affordances for locomoting between gaps in a handrail. The findings suggest that weeks of cruising do not teach infants a basic fact about walking: the necessity of a floor to support the body. Moreover, this research demonstrated that developmental milestones that are temporally contiguous and structurally similar might have important functional discontinuities

Editorial: Modeling Play in Early Infant Development

International audienc

Exploration in the service of prospective control

Abstract We propose a sequential process of exploration that can account for perception-action coupling in infant locomotion. Each phase in the sequence is a process of obtaining progressively more information leading to a motor decision-exploration from a distance, exploration via direct contact, and exploration of alternative means. Quick glances and prolonged looking from afar serve to alert the perceiver to important changes in the terrain. Intentional touching and testing alternative ways to traverse an obstacle are only prompted when prior information indicates a potential threat to balance. We further propose that depth information is privileged because it can be detected from a distance more readily than other surface properties such as rigidity and friction. Studies of infants walking down slopes and across "hole/patch" transitions illustrate the important role of exploration in prospective control of locomotion

Oh, Behave!

Behavior is essential for understanding infant learning and development. Although behavior is transient and ephemeral, we have the technology to make it tangible and enduring. Video uniquely captures and preserves the details of behavior and the surrounding context. By sharing videos for documentation and data reuse, we can exploit the tremendous opportuni-ties provided by infancy research and overcome the important challenges in studying behavior. The Datavyu video coding software and Databrary digital video library provide tools and infrastructure for mining and sharing the richness of video. This article is based on my Presidential Address to the International Congress on Infant Studies in New Orleans, May 22, 2016 (Video 1 at https://www.databrary.org/volume/955/slot/39352/-?asset=190106. Given that the article de-scribes the power of video for understanding behavior, I use video clips rather than static images to illustrate most of my points, and the videos are shared on the Databrary library