Do Developmental Dyscalculic Children have Spatial Biases in Processing Numbers? Evidences from Snarc effect

Abstract

Developmental dyscalculia (DD) is a specific learning disability affecting the normal acquisition of arithmetic skills, it is hypothesized that they may be lacking ability to represent and manipulate numerical magnitude nonverbally on an internal number line. Hence the present study was attempted with the aim of observing spatial biases if any in children with developmental dyscalculia using spatial numerical association of response codes (SNARC) paradigm. Participants consisted of 12 children with developmental dyscalculia and thirty typically developing children in the age range of 9-10 years. Each participant received four white pages containing written instructions on the first page; and the other 2 pages contained 16 strings of digits and the other with 16 lines. All participants were instructed to bisect each stimulus in the middle. The distance between a bisection mark and both ends of a line was determined to the nearest millimeter, yielding a left and right interval for each stimulus. The difference score (left interval minus right interval) yielded a negative value when performance was biased to the left and a positive value when performance was biased to the right. The results revealed no evidence of SNARC effect in both the groups of children i.e., normal controls exhibited a right handed bias for both small and large numbers and left handed bias for lines whereas children with developmental dyscalculia exhibited a left sided bias for both lines and numbers. In the present study, we investigated spatial biases if any while processing numbers in children with developmental dyscalculia. The results revealed no evidence of SNARC effect in both the groups of children. The present observations, if substantiated by further research, may be useful for the diagnosis of number comprehension skills in children with developmental dyscalculia.