Descartes's blind man revisited: bimanual triangulation of distance using static hand-held rods.

Analogous to binocular convergence, we tested Descartes's proposal that a blind person could triangulate distances using crossed hand-held rods by sensing hand separation and wrist angles. In Experiment 1, 22 participants judged distances to loci at 4 distances, 18-36 in. (45.