How visual experience and task context modulate the use of internal and external spatial coordinate for perception and action.

Recent studies proposed that the use of internal and external coordinate systems for perception and action may be more flexible in congenitally blind when compared to sighted individuals. To investigate this hypothesis further, we asked congenitally blind and sighted people to perform, with the hands uncrossed and crossed over the body midline, a tactile temporal order judgment and an auditory Simon task. Crucially, both tasks were carried out under task instructions either favoring the use of an internal (left vs.