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The development of infants' reaches for stationary and moving targets
N Wentworth1, J B Benson, M M Haith
1Department of Psychology, Lake Forest College, IL 60045, USA. wentworth@lfc.edu
Insights
Infants develop reaching skills by adjusting hand movements and using target motion information. This study reveals how anticipation and updating refine manual skills in early development.
Area of Science:
- Developmental Psychology
- Motor Skill Acquisition
- Infant Perception-Action
Background:
- Understanding the development of reaching skills in infants is crucial for cognitive and motor development research.
- Previous studies have explored reaching in controlled environments, but less is known about adaptation to dynamic targets.
Purpose of the Study:
- To examine the organization of infants' reaching skills for both stationary and moving targets.
- To investigate the roles of anticipation and updating in the development of early manual skill.
Main Methods:
- Observed 58 healthy infants (5.5, 8.5, 11.5 months) reaching for stationary and moving targets.
- Utilized slow-motion video analysis to assess hand alignment, target updating, and depth perception.
- Analyzed anticipatory adjustments and use of dynamic target information.
Main Results:
- Infants at all ages demonstrated anticipatory hand alignment, with effectiveness increasing with age.
- Infants used dynamic target information to update reaches, with age-related differences in information utilization.
- Reaching for approaching targets showed developmental constancy across age groups.
Conclusions:
- Infants' reaching skills adapt to target dynamics, showing increasing sophistication with age.
- Anticipation and updating are key components in the development of adaptive reaching.
- This research expands understanding of early manual skill under diverse conditions.
Abstract:
The organization of infants' reaching skill for stationary and moving targets was examined. While 58 term, healthy infants at 5.5, 8.5, and 11.5 months of age reached for and grasped a cloth-covered dowel, their reaches were videotaped for later slow-motion analysis. Analyses addressed infants' anticipatory adjustment of hand alignment, use of information from spinning and oscillating targets to update ongoing reaches, and ability to capture targets moving in depth. Infants at all ages made anticipatory adjustments of hand alignment, although the effectiveness of these adjustments improved with age. Regardless of age, infants also used dynamic information from spinning and oscillating targets to update ongoing reaches, but the way infants used this information was related to age. Developmental constancy characterized infants' reaches for approaching targets. By observing infants' reaches for stationary, spinning, and approaching targets, the study expands the range of conditions under which adaptive reaching skill has been examined and provides insight into the roles of anticipation and updating in the development of early manual skill.