Multidimensional scaling of alphabetic confusion matrices for the right and left visual fields

The present study attempted to determine possible differences in representations obtained from letter confusion matrices for the left and right visual fields.Fifteen right handed male subjects (no familial sinistrality) were required to identify single letters from a previously learned subset of the English alphabet. The stimuli were presented briefly at 5 degrees from central fixation in the right and left visual fields to ensure transmission to the hemisphere contralateral to the side of presentation.Data were cast in the form of 8 x 8 matrices. Luce's Index of confusability provided an interval scale representation of errors (Luce, 1959). The KYST algorithm was used to generate representations of the confusion matrices for the left visual field and right visual field data and determine goodness-of-fit of the representation.Multidimensional scaling of error patterns and vocal reaction times indicated no difference between visual fields in representation though a right visual field advantage was found for accuracy.The discussion considered the results in terms of the possible operation of a hierarchial decision process in letter recognition and examined inconsistencies in existing theories of hemispheric asymmetry.