Mapping letters to numbers: Potential mechanisms of literal symbol processing

Abstract

This study examined impermanent symbol-referent connections (e.g., x = 5) with literal symbols – important symbols for higher-level mathematics that may be difficult to process due to interference from pre-existing associations from literacy. We examined literal symbol processing at the group and individual levels, and executive functioning and symbol-referent mapping ability as potential cognitive mechanisms. Participants completed same-different judgments using numbers, literal symbols, and novel symbols; symbol-referent mapping; and executive function tasks. On average, participants' judgments with literal symbols took longer than with other symbols (i.e., a literal symbol processing cost). Individual differences in this cost were associated with variability in literal symbol mapping performance, but not with executive functioning. Results suggest the processing cost results from learning symbol-referent connections with symbols that have prior associations, and identifies initial symbol-referent mapping ability as a potential mechanism that contributes to this difficulty. Findings provide novel characterization of symbolic number processing relevant for higher-level mathematics.