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ERIC Number: EJ894926
Record Type: Journal
Publication Date: 2010-Dec
Pages: 15
Abstractor: As Provided
Reference Count: 0
ISBN: N/A
ISSN: ISSN-0022-0965
Developmental Changes during Childhood in Single-Letter Acuity and Its Crowding by Surrounding Contours
Jeon, Seong Taek; Hamid, Joshua; Maurer, Daphne; Lewis, Terri L.
Journal of Experimental Child Psychology, v107 n4 p423-437 Dec 2010
Crowding refers to impaired target recognition caused by surrounding contours. We investigated the development of crowding in central vision by comparing single-letter and crowding thresholds in groups of 5-year-olds, 8-year-olds, 11-year-olds, and adults. The task was to discriminate the orientation of a Sloan letter E. Single-letter thresholds, defined as the stroke width forming the smallest discriminable E, were worse than those of adults (0.83 arcmin) at 5years of age (1.05 arcmin) but not at older ages (8-year-olds: 0.81 arcmin; 11-year-olds: 0.78 arcmin). The maximum distances over which crowding occurred, as measured in multiples of threshold stroke width, were smaller in adults (2.83) than in the three groups of children, who did not differ from each other (5-year-olds: 7.03; 8-year-olds: 7.84; 11-year-olds: 7.13). Thus, even 11-year-olds are more affected than adults by surrounding contours despite having single-letter acuity that has been mature for several years. The stronger influence of crowding in children may be caused by immaturities in the brain areas beyond the primary visual cortex (V1) where early visual inputs are combined and may contribute to their slower reading speed. (Contains 5 figures.)
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A