What do semi-illiterate adults know about 2-digit Arabic numbers?
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, what eliminates the semantic interference of units. In line with previous research, our data suggest that unit-decade segmentation plays a pervasive role in Arabic number comparison.
Wood
Guilherme
G
Department of Neurology, Section Neuropsychology, University Hospital RWTH-Aachen, Aachen, Germany. gwood@ukaachen.de
Nuerk
Hans C
HC
Freitas
Patrícia
P
Freitas
Gianna
G
Willmes
Klaus
K
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D003210:Concept Formation / Q000502:physiology*; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D012660:Semantics; D014706:Verbal Learning / Q000502:physiology*