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Infant Object Catching

Reaching as Yardstick for Early Infant Physical Knowledge

 

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As early as 16 weeks of age, human infants develop the motor coordination necessary to reach out and grasp stationary objects. At that same age they simultaneously begin to reach out and catch moving objects. Since reaching actions require time to plan and execute, catching a moving target requires the infants to direct their action ahead of the target, not to the location in which they currently see it. Their action must be oriented toward the position that the object will occupy approximately 500-750 msec in the future.

The "future oriented" nature of this behavior is depicted in this brief movie (courtesy of Claes von Hofsten, Upsalla, Sweden). Even though the object abruptly stops, the infant has already gathered all of the perceptual information that she needs to perform the action. As such, she reaches for the point in space that the object would have occupied had it continued to move. The expression on her face is consistent with the notion that she expected to catch it.

By presenting babies with a target that moves along several different paths of motion, it is possible to infer what sources of information infants use to infer the future motion of the object, providing a better understanding of how infants reason about the physical world during the first months of life.