The kinaesthetic perception of Euclidean distance: a study of the detour effect

Abstract

An experiment investigated the mechanisms by which humans estimate Euclidean distances on the basis of kinaesthetic cues. Blindfolded participants followed straight and curvilinear paths with a hand-held stylus (encoding phase). Then, with a straight movement, they estimated the Euclidean distance between the start-and end-points of the path (response phase). The experiment contrasted an On-axis condition, in which encoding and response movements were spatially aligned, and an Offaxis condition, in which they were displaced laterally. Performances were slightly more accurate in the On-axis condition than in the Off-axis condition. In both conditions, however, errors were consistently smaller when the path covered a larger surface. The results showed that small paths yielded an overestimation of the Euclidean distance, the relative errors increasing with the length of curvilinear paths. The findings are compared with results of other studies in which distances were estimated on the basis of haptic cues.

Attenuating the haptic horizontal—vertical curvature illusion

“…This is the idea that the movements that one makes can influence judgments of extent. Increases in path length prompted increases in the judged distance between endpoints (also see Faineteau, Gentaz, & Viviani, 2003. It is possible that the subjects overestimated the verticals of the curves in Experiment 1-in part, because of increases in movement extent while scanning the curved pathway.…”

“…In the path completion problem, subjects feel a curve and then judge the distance between endpoints (see Faineteau et al, 2003Faineteau et al, , 2005Lederman et al, 1985). They are not permitted to actually feel the distance between endpoints, and the subjects in Experiment 1 were prevented from scanning between endpoints.…”

A brief taxonomy of tactile illusions and demonstrations that can be done in a hardware store

“…The directions in which the pencils point will be quite different. Recently, a new series of studies reveals a variety of new effects involving this type of judgments, in conjunction with vision [7], complex movements [26], and force cues [88]. In this section we may also include an effect described by Cormack that involves rotating a disk using two passive fingers of one hand and two active fingers from the other [15].…”

Geometrical haptic illusions: The role of exploration in the Müller-Lyer, vertical-horizontal, and Delboeuf illusions

“…In the first case, the lines that induce the visual error might not be perceived by the hand, and the haptic illusion may not appear. (2) The interventionof the kinesthetic information resulting from large exploratory movements (when the arm-hand system is involved in the perception of a large stimulus) could produce spatial distortions (Faineteau, Gentaz, & Viviani, 2003;Klatzky, 1999;Lederman, Klatzky, & Barber, 1985;Lederman, Klatzky, Collins, & Wardell, 1987). (3) The gravitational cues generated by the antigravity forces allowing the arm to be kept in the air may provide reference cues not present in the visual illusion (Gentaz & Hatwell, 1996, 1998, 1999Heller, Calcaterra, Burson, & Green, 1997).…”