Symbolic and non-symbolic number representations are
thought to share common neural substrates. However, recent
studies have shown that the two numerical systems are more
distinct than previously thought. These disparate findings may
be explained by the use of sequential presentations of symbolic
and non-symbolic quantities, the use of magnitude-reliant
tasks, or the use of limited number ranges. We investigated
whether adults integrate symbolic and non-symbolic numerical
information during a non-magnitude-based task in which
symbolic and non-symbolic double-digit numerical information
is shown simultaneously. Participants viewed images
in which symbolic numerals or letter pairs were superimposed
on non-symbolic numerical stimuli and were asked to determine
whether the text was a numeral or letter, ignoring the
dots. After perceptual biases were taken into account, participants
were more accurate and faster in their judgments when
symbolic and non-symbolic information matched than when
information mismatched, suggesting that adults can integrate
symbolic and non-symbolic numerical information