An Investigation of Number-Space Associations: Exploring Developmental and Cognitive Influences

In order to comprehend higher order arithmetic it is of crucial importance to get a thorough understanding of basic number processes. One of the basic characteristics of numerical representations is its association to space. Empirical evidence for the number-space association is the SNARC effect (Spatial Numerical Associations of Response Codes, Dehaene et al., 1993): in binary classification judgments participants are faster responding to small/large digits on the left/right response side respectively. However, only 65-75% of participants display this signature effect of number-space associations (Wood et al., 2006a; 2006b). Although some influencing factors on the SNARC effect such as response speed and writing habits (Gevers et al., 2006; Shaki et al., 2009) have been identified, research on this issue remains scarce. Another question mark in the number-space research is the ontogenetic emergence and evolution of the numerical-spatial relationship. The present work gives a brief overview of what is known about the number-space association and adds empirical data to existing scientific knowledge. Specifically we found that number-space associations in the form of a SNARC effect emerge early in life (from age 5.5) and that its relationship to basic number knowledge at that age depends on the task at hand. Moreover, in adults, arithmetic proficiency, as well as interference inhibition capacities are related to the strength of the SNARC effect. A very strong relationship exists between the strength of the SNARC effect and chronological age, as the SNARC effect becomes stronger with increasing age.