Figure 4.

Spatial number representation revealed by systematic reach-trajectory shifts from Song & Nakayama [74]. Participants are shown a single-digit Arabic numeral in a centre square and asked to compare its value with the standard, 5. They then reach for and touch one of three squares on the screen: the left for ‘less than’, the centre one for ‘equal to’ or the right one for ‘greater than’. The panels in this figure depict examples in which the value of the target is ‘equal to’ (a) or ‘less than’ (b–e) the standard. The lower panels demonstrate gradual shifts of reach trajectories towards the centre square as the difference in value between the target and the standard decreases. These trajectories are three dimensional, but for clarity, the most relevant x (left–right) and y (upward–downward) dimensions are plotted.