Biomedical subjects

K E Adolph

Publications and source records attributed to K E Adolph.

5 recordsLinked to original sources

PubMed2000

Walking infants adapt locomotion to changing body dimensions.

Infants acquire independent mobility amidst a flux of body growth. Changes in body dimensions and variations in the ground change the physical constraints on keeping balance. The study examined whether toddlers can adapt to changes in their body dimensions and variations in the terrain by loading them with lead weights and observing how they navigated safe and risky slopes. Experiment 1 verified the reliability of a new psychophysical procedure for testing infants' responses in 2 experimental conditions. In Experiment 2, this procedure was used to compare infants' responses on slopes in feather-weight and lead-weight conditions. The lead weights impaired infants' ability to walk down slopes. Babies adapted to altered body dimensions by treating the same degree of slope as safe in the feather-weight condition but as risky in the lead-weight condition. Exploratory activity on the starting platform predicted adaptive responses on risky slopes.

Adaptation, Physiological↗

PubMed1998

Learning to crawl.

The effects of infants' age, body dimensions, and experience on the development of crawling was examined by observing 28 infants longitudinally, from children's first attempts at crawling until they began walking. Although most infants displayed multiple crawling postures en route to walking, development did not adhere to a strict progression of obligatory, discrete stages. In particular, 15 infants crawled on their bellies prior to crawling on hands and knees, but the other 13 infants skipped the belly-crawling period and proceeded directly to crawling on hands and knees. Duration of experience with earlier forms of crawling predicted the speed and efficiency of later, quite different forms of crawling. Most important, infants who had formerly belly crawled were more proficient crawling on hands and knees than infants who had skipped the belly-crawling period. Transfer could not be explained by differences in infants' age or body dimensions alone. Rather, experience using earlier crawling patterns may have exerted beneficial effects on hands-and-knees crawling by shoring up underlying constituents common to all forms of crawling postures.

Age Factors↗

PubMed1997

Learning in the development of infant locomotion.

Infants master crawling and walking in an environment filled with varied and unfamiliar surfaces. At the same time, infants' bodies and skills continually change. The changing demands of everyday locomotion require infants to adapt locomotion to the properties of the terrain and to their own physical abilities. This Monograph examines how infants acquire adaptive locomotion in a novel task--going up and down slopes. Infants were tested longitudinally from their first week of crawling until several weeks after they began walking. Everyday locomotor experience played a central role in adaptive responding. Over weeks of crawling, infants' judgments became increasingly accurate, and exploration became increasingly efficient. There was no transfer over the transition from crawling to walking. Instead, infants learned, all over again, how to cope with slopes from an upright position. Findings indicate that learning generalized from everyday experience traveling over flat surfaces at home but that learning was specific to infants' typical method of locomotion and vantage point. Moreover, learning was not the result of simple associations between a particular locomotor response and a particular slope. Rather, infants learned to gauge their abilities on-line as they encountered each hill at the start of the trial. Change in locomotor responses and exploratory movements revealed a process of differentiation and selection spurred by changes in infants' everyday experience, body dimensions, and locomotor proficiency on flat ground.

Child Development↗

PubMed1995

Psychophysical assessment of toddlers' ability to cope with slopes.

This research examined how infants in early stages of walking determine whether a hill is safe or risky for locomotion. A psychophysical staircase procedure provided estimates of infants' physical ability to walk up and down slopes (2 degrees to 36 degrees), and a "go ration" indexed the accuracy of their perceptual judgments. On average, perceptual judgments were scaled to walking ability on slopes. Children walked on safe slopes and balked on risky ones. For ascent, perceptual judgments were related to length of walking experience and walking skill on flat ground. Better walkers were also better perceivers. For descent, judgments neatly mirrored exploratory activity. Better perceivers explored hills more efficiently by hesitating, touching, and testing different positions on hills around the limits of their physical ability.

Exploratory Behavior↗

PubMed1993

Crawling versus walking infants' perception of affordances for locomotion over sloping surfaces.

14-month-old toddlers vs. 8.5-month-old crawling infants were encouraged to ascend and descend a sloping walkway (10 degrees, 20 degrees, 30 degrees, and 40 degrees). Infants in both locomotor groups overestimated their ability to ascend slopes. However, on descending trials where falling was more aversive, most toddlers switched from walking to sliding positions for safe descent, but crawlers plunged down head first and many fell at each increment. Toddlers touched and hesitated most before descending 10 degrees and 20 degrees slopes, and they explored alternative means for descent by testing out different sliding positions before leaving the starting platform. In contrast, crawlers touched and hesitated most before descending 30 degrees and 40 degrees slopes, and they never explored alternative sliding positions. In addition, we analyzed measures of locomotor skill and experience in relation to children's ability to perceive affordances. Findings indicate that children must learn to perceive affordances for locomotion over slopes and that learning may begin by fine-tuning of exploratory activity.

Attention↗