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Effects of flanker type and position on foveal letter recognition

Mohd Izzuddin Hairol, Qazi Mohamad Omair, Sharanjeet Kaur
2016 F1000Research  
Discuss this article (0) Comments 2 1 Abstract Our ability to identify a foveally viewed letter at resolution threshold reduces when flankers are placed at a certain distance from it, compared to when it is presented on its own. In this study, we investigated how type and position of flankers influences foveal letter recognition. We measured participants' performance to identify unflanked Sheridan-Gardiner letters (A, H, O, U, T, V or X), using a seven-alternative-forced-choice paradigm with
more » ... ce paradigm with the method of constant stimuli to obtain 80-90% correct response. Performance was measured again to identify a target letter in the presence of different flanker types. Flankers were bars and letters (placed either to the left and right of the target, above and below the target or on four sides of the target), and a surrounding box. Separation between the target letter and flankers varied between zero (abutting) and ten stroke widths (two letter sizes). For all flanker types, separation between the target ad the flankers significantly influenced performance (all < 0.0001). Flankers abutting the target and at separation of p one stroke width caused the largest reduction in performance, regardless of flanker type. For bar flankers, the largest drop in performance (up to 50 percent) occurred with bars placed on all four sides of the target. For letter flankers, flankers placed above and below the target reduced performance as much as four surrounding flankers. At separation of one stroke width, flanking letters and bars caused a further 10% reduction in performance than a surrounding box. Our results would have significant implications on the design of crowded visual acuity charts, especially those that are available on the market, which have different crowding features between them. Mohd Izzuddin Hairol ( ) Corresponding author: izzuddin.hairol@ukm.edu.my Hairol MI, Omair QM and Kaur S. How to cite this article: Effects of flanker type and position on foveal letter recognition [version 1; 2016, :1013 (doi: ) referees: 1 approved, 1 approved with reservations] F1000Research 5 PubMed Abstract | Publisher Full Text Banks WP, White H: Lateral interference and perceptual grouping in visual detection. Percept Psychophys. 1984; 36(3): 285-295. PubMed Abstract | Publisher Full Text Bedell HE, Siderov J, Formankiewicz MA, et al.: Evidence for an eye-movement contribution to normal foveal crowding. Optom Vis Sci. 2015; 92(2): 237-245. 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PubMed Abstract | Publisher Full Text The title and abstract are appropriate and accurately reflect the content of the article. Study design and methodology are sound and reflect the aims of the study. The conclusions are valid.
doi:10.12688/f1000research.8572.1 fatcat:axeqjncnyfedbibymiu3cyb7ne