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Tachistoscopic recognition of vertical and horizontal letter symmetry in response to the contralateral organization of the human nervous system

Eight-letter upper case arrays containing vertically symmetrical (VS), e.g., A-T-U-W, horizontally symmetrical (HS), e.g., B-D-C-E, doubly symmetrical (DS), e.g., H-I-O-X, and non-symmetrical (NS), e.g., F-G-L-R, were tachistoscopically exposed bilaterally for 50 ms. to fifteen male and fifteen female undergraduates. The number of letters correctly recognized for each classification condition was used as the criterion measure. A fixed, two-factor design with the second factor being repeated was analyzed using a repeated measures analysis of variance. Consequent to testing Null Hypothesis 1 (that there is no difference between the classification conditions), a check was made for the presence of a significant interaction between gender and classification condition (Null Hypothesis 2). Because Null Hypothesis 1 was rejected and there was no interaction present, the classification group means were tested using a post hoc multiple comparison procedure identified as Tukey's Honestly Significant Difference (HSD) test. Test statistics for the Tukey HSD contrasts found that significantly more VS letters were reported than DS, HS, and NS letters. Significantly more DS letters were reported than HS and NS letters. No difference in report accuracy was found between HS and NS letters. This is in sharp contrast to studies that count only responses reported in the same left-to-right order as the tachistoscopic presentation, i.e., order of report. Previous studies using an order of report method found vertically asymmetrical letters to be reported more accurately than vertically symmetrical ones. The present study disregarded order of from an order of report. It was emphasized that the subject maintain focus on the fixation dot and not attempt to scan the letter-array pattern in a left-to-right direction, as the lettersdid not have to be reported in their respective positions. A different explanation for the Harcum (1964) directionality and Bryden (1968) masking interpretations follows from an order of report method activating additional processing mechanisms such as working memory that are ordinarily not needed to process letter features.Results obtained by the present study are discussed in terms of a reversal of spatial information for touch, kinesthesis, and sound to match the brain’s reversed retino-cortical projection. / Department of Educational Psychology

Identiferoai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/182265
Date January 2001
CreatorsZukauskis, Ronald L.
ContributorsDean, Raymond S.
Source SetsBall State University
Detected LanguageEnglish
Formativ, 79 leaves : charts ; 28 cm.
SourceVirtual Press

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