Pointing to numbers and grasping magnitudes.

The cognitive representation of numbers has been studied with chronometric methods but these cannot resolve the current debate about the metrical structure of the "mental number line". We recorded spatial behaviour as blindfolded adults described the locations of numbers (e.g., "where is 3?") by pointing and the lengths of magnitudes (e.g., "how much is 56?") by gesturing. Their unconstrained spatial behaviour revealed idiosyncratic spatial associations for numbers and largely supports a linear representation of magnitudes.