Smets, K. , Gebuis, T. & Reynvoet, B.
University of Leuven
Non-symbolic quantities are represented with overlap between numerically close quantities. This overlap underlies the so-called ‘distance effect’, which is assumed to be a measure of numeric processing and is suggested to relate to mathematical performance. Adult participants are usually tested with comparison or same-different tasks. Recently, some doubt has been casted on whether these tasks are comparable and whether the distance effects derived from the tasks all originate at the same level. In the current study, comparison and same-different tasks were contrasted on a behavioral and a neural level. Careful precautions were taken to ensure that participants were not able to rely on visual cues which are associated with number while doing the task. On a behavioral level (i.e., reaction times), the correlation between the comparison distance effect and the same-different distance effect did not reach significance. The neural results obtained with electroencephalography were in the same line as the behavioral data. This seems to indicate a different origin for both distance effects which suggests that comparison and same-different tasks may not be entirely comparable.