Crossing effects in temporal order judgment (TOJ) have been interpreted to indicate remapping of touch from somatotopic into external spatial coordinates. Such crossing effects have been reported to be absent in the congenitally blind, presumably indicating that they do not, by default, remap touch (e.g. 1).
Here, we devised a TOJ task in which participants, trial by trial, took on an uncrossed or crossed start posture and executed a cued movement with both arms into an uncrossed or crossed end posture. When stimulated during movement planning (i.e. before movement execution into the end posture), sighted participants' performance was affected both by start posture (i.e. the posture during stimulation) as well as end posture (i.e. the currently planned posture). In contrast, blind participants showed a crossing effect for the start posture, but no effect of end posture.
Thus, the blind do seem to remap touch when hand posture must be explicitly coded to perform the task such as when planning hand movements. However, whereas the sighted relate touch not only to current, but also to planned future postures, the blind seem to restrict remapping to current posture.