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Published on: June 1, 2015
Effects of support surface and optic flow on step-like movements in pre-crawling and crawling infants
David I Anderson1, Yuka Kobayashi1, Kate Hamel1
1Department of Kinesiology, San Francisco State University, San Francisco, CA, United States.
Insights
Pre-crawling infants exhibit more airborne step-like movements than on surfaces. Crawling infants show no difference, suggesting leg weight may influence infant stepping development.
Area of Science:
- Developmental Psychology
- Motor Development
- Infant Behavior
Background:
- Infant stepping reflexes are transient, often disappearing before independent walking.
- Theories suggest leg mass increase may inhibit the stepping pattern.
Purpose of the Study:
- To investigate the influence of support surface and visual flow on infant step-like movements.
- To compare movement patterns in pre-crawling versus crawling infants.
Main Methods:
- Observing 18 infants (6-13 months) divided into pre-crawling and crawling groups.
- Assessing step-like movements in air and on-surface conditions.
- Presenting static visual patterns and optic flow stimuli.
Main Results:
- Pre-crawling infants showed significantly more step-like movements in air than on a surface.
- Crawling infants exhibited similar numbers of step-like movements in both conditions.
- Optic flow did not affect the frequency of step-like movements in either group.
Conclusions:
- Findings support the hypothesis that increased leg weight may contribute to the disappearance of infant stepping.
- Motor development and postural support interact to modulate early locomotor behaviors.
Abstract:
Step-like movements were examined in pre-crawling (n=9) and crawling (n=9) 6-13 month-old infants in the air and on a surface in response to a static pattern or optic flows that moved toward or away from the infant. Infants completed six 60-s trials. A significant interaction between locomotor status and support condition revealed that pre-crawling infants made more step-like movements in the air than on a rigid surface. In contrast, crawling infants made an equivalent number of step-like movements in the air and on the surface. Optic flow did not influence the number of step-like movements made by infants. The pre-crawling infant finding is consistent with a finding in a previous study in which two month-old infants were shown to step more in the air than on the ground. This finding is discussed relative to the idea that the infant stepping pattern disappears because the legs become too heavy to lift.
