What do semi-illiterate adults know about 2-digit Arabic numbers?
Wood G; Nuerk HC; Freitas P; Freitas G; Willmes K Department of Neurology, Section Neuropsychology, University Hospital RWTH-Aachen, Aachen, Germany. gwood@ukaachen.de Brazilian semi-illiterates (n=19) with 1 to 4 years of academic training compared 2-digit Arabic numbers. Like competent readers, semi-illiterates responded faster and more accurately when the larger number also had the larger unit digit (unit-decade compatibility). Even semi-illiterates with minimal academic training were sensitive to the unit-decade compatibility on number comparison. Probably semi-illiterates derive their ability to automatically activate unit-decade segmentation directly from the oral/verbal number representation. Interestingly, processing speed had an effect on two-digit number comparison. Faster participants showed a smaller or even inverted unit-decade compatibility. Processing speed reflects increased automatization of number segmentation and better selection of the decade-digits for comparison,
