Beyond numbers: the origin of spatial associations of ordinal information

The great interest on the origin of space-number associations has motivated recent investigation on spatial compatibility effects (e.g., the SNARC effect) induced by over-learned non-numerical sequences (e.g., letters, months). The work included in the present thesis aims to contribute to our understanding of the determinants of the spatial mapping of ordinal information, including both numbers and other general series. Firstly, the increasing evidence of the link between finger counting and number processing has been considered, in particular the specific role of handedness on this interaction and the influence of finger counting direction on number mapping in the representational space. Results showed that handedness fully predicts finger counting direction and that the directional asymmetries of finger counting are not relevant for shaping the mental representation of numbers. Secondly, the peculiarity of numbers evoking a spatially organized mental representation has been argued, showing that the oriented spatial representation is the privileged way of mentally organizing serial information, even newly acquired arbitrary sequences. Finally, a potential explanation for ordinal spatial associations has been evaluated, analyzing the role of working memory in determining the spatial compatibility effects of serial information observed with numerical and non-numerical sequences as stimuli.