Looking into the Calculating Mind: Evidence About Arithmetic from Eye-Tracking Studies.

The investigation of eye movements has been shown to provide valuable insights into a variety of cognitive processes. A limited number of recent studies have adopted eye-tracking to investigate the processes underlying simple and complex arithmetic. Here, we review and discuss these studies. We identify two lines of research: While some studies have focused on the spatial-arithmetic associations emerging during arithmetic problem solving, some others have examined the use of procedures, strategies, and rules. Generally, results point to the added value of eye-tracking as a method for investigating different underlying processes during mental arithmetic. Altogether, eye-tracking does not only confirm the evidence gained from "pure" behavioral studies, but it also gives new insights, in particular with regard to temporal dynamics, problem difficulty, use of strategies, and inter-individual differences. Such an approach holds great potential for the studying of arithmetic not only in healthy individuals but also in clinical populations.