Cross-format physical similarity effects and their implications for the numerical cognition architecture

• We assess RT in numerical cross-format comparison tasks.
• Physical similarity predicts RT for numerical cross-format same/different tasks.
• Physical similarity and distance effects predict RT for magnitude comparison tasks.
• The data support direct links between format modules.
• The data support format specific quantity representations.

The sound |faɪv| is visually depicted as a written number word “five” and as an Arabic digit “5.” Here, we present four experiments – two quantity same/different experiments and two magnitude comparison experiments – that assess whether auditory number words (|faɪv|), written number words (“five”), and Arabic digits (“5”) directly activate one another and/or their associated quantity. The quantity same/different experiments reveal that the auditory number words, written number words, and Arabic digits directly activate one another without activating their associated quantity. That is, there are cross-format physical similarity effects but no numerical distance effects. The cross-format magnitude comparison experiments reveal significant effects of both physical similarity and numerical distance. We discuss these results in relation to the architecture of numerical cognition.