Presentation Title

Stable Without a Table: Does the Development of Visually Guided Reaching and Grasping Depend on Stabilization of the Hand?

Format of Presentation

Poster to be presented Friday March 31, 2017

Abstract

Prehension, the act of reaching and grasping, is believed to be mature and under visual control in 12-month-old infants. Multiple Motor Channel (MMC) theory contests this, claiming that separate reach and grasp movements originate under tactile control, with visual integration of these movements occurring much later. Our prior research provides preliminary support for MMC theory, by showing that 12-month-old infants appear to depend on tactile support from a table when reaching to grasp Cheerios. If MMC theory is correct, we expect to find that taking away the table support will impair the infants’ ability to reach out and grasp Cheerios. In contrast, if infants are able to accurately reach out and grasp the Cheerio, this would provide evidence that by 12 months of age, the reach and grasp are fully integrated under vision. To test this, we placed a Cheerio on a 10x2x2 cm pedestal and video-recorded the reach and grasp movements of the 12-month-old infants as they reached for it. We compared their movements to that of sighted and unsighted adults. We expect that infants’ reach and grasp movements will resemble that of unsighted adults in that: 1) they will not integrate under visual control, 2) they will not preshape their hands while reaching, and 3) they will be impaired without tactile support from the table. A better understanding of the sensorimotor development of hand movements in healthy infants will allow us to better identify and treat hand impairments in infants with developmental disorders.

Department

Psychology

Faculty Advisor

Jenni M. Karl

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Stable Without a Table: Does the Development of Visually Guided Reaching and Grasping Depend on Stabilization of the Hand?

Prehension, the act of reaching and grasping, is believed to be mature and under visual control in 12-month-old infants. Multiple Motor Channel (MMC) theory contests this, claiming that separate reach and grasp movements originate under tactile control, with visual integration of these movements occurring much later. Our prior research provides preliminary support for MMC theory, by showing that 12-month-old infants appear to depend on tactile support from a table when reaching to grasp Cheerios. If MMC theory is correct, we expect to find that taking away the table support will impair the infants’ ability to reach out and grasp Cheerios. In contrast, if infants are able to accurately reach out and grasp the Cheerio, this would provide evidence that by 12 months of age, the reach and grasp are fully integrated under vision. To test this, we placed a Cheerio on a 10x2x2 cm pedestal and video-recorded the reach and grasp movements of the 12-month-old infants as they reached for it. We compared their movements to that of sighted and unsighted adults. We expect that infants’ reach and grasp movements will resemble that of unsighted adults in that: 1) they will not integrate under visual control, 2) they will not preshape their hands while reaching, and 3) they will be impaired without tactile support from the table. A better understanding of the sensorimotor development of hand movements in healthy infants will allow us to better identify and treat hand impairments in infants with developmental disorders.