Infant learning about balance control across changes in body postures

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INFANT LEARNING ABOUT BALANCE CONTROL ACROSS CHANGES IN BODY POSTURES Karen E. Adolph, Anthony M. Avolio, Katherine E. Melton, Heather S. Arnet, Marion A. Eppler Department of Psychology, New York University, New York, NY 10003 Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213 Department of Psychology, Eastern Carolina University, Greensville, NC 27858

Infants spend much of their first year of life coping with balance control in a series of increasingly difficult postures: first sitting, then crawling, then cruising, and finally walking. Previous research indicates that infants learn about balance control from everyday experience on safe, flat ground (Adolph, 1997). Learning to keep balance in experienced postures transfers to novel situations on slopes; however, learning does not transfer from crawling to walking postures. The current research expands on previous work by examining transfer and specificity of learning in a novel B task. We tested 9.5-month-old infants in two different body postures-an experienced sitting posture (M = 101 days) and a less familiar crawling posture @$ = 45 days)-as they leaned out over safe and risky gaps in the floor. A psychophysical staircase procedure (Adolph, 1997) identified the widest gaps infants could manage in each posture-their gap boundaries. A go ratio [(attempts to go) / (attempts + avoidance)] indexed infants’ judgments on safe and risky gaps. Perfect judgments would be indicated by a high go ratio on gaps narrower than infants’ boundaries (safe gaps) and a low go ratio on gaps wider than infants’ boundaries (risky gaps).

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Results indicate that infants’ knowledge about balance control transfers from everyday experience on solid ground to novel variations in the surface of support. In both sitting and crawling postures, infants’ judgments were scaled to their gap boundaries (go ratios decreased on increasingly risky gaps). However, learning does not transfer from experienced postures to less familiar ones. Infants made fewer errors (lower go ratios) on risky gaps in an experienced sitting posture than in a less familiar crawling posture. Apparently, everyday experience facilitates learning to cope with balance control, but only for particular vantage points and muscle groups. --o--

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Gap Width (cm) Relative to Boundary Adolph, K.E. (1997). Learning in the development

of infant locomotion.

Child Development, 61(3, Serial No. 251).

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