Mechanisms in the haptic horizontal-vertical illusion: Evidence from sighted and blind subjects

Abstract

The haptic horizontal-vertical illusion was studied in two experiments. In Experiment 1, the illusion was relatively weak in sighted subjects and depended on stimulus size and the nature of the figure, that is, whether the pattern was an inverted-T or L shape. Experiment 2 compared early blind and late blind subjects. The illusion was present for an inverted-T figure but absent for an L figure in late blind subjects. However, the early blind subjects treated both the Land T figures as similar and showed the illusion to both. These results support the idea that visual experience may alter haptic judgments in sighted and late blind subjects.Many researchers have been interested in discovering what tactile illusions can tell us about spatial perception (

Analysis of individual variations in the classical horizontal-vertical illusion

“…If the same factors influence the strength of the illusion in both domains, this indicates similar perceptual processes underlying the illusion. It could be shown that bisection effects and vertical overestimation are also present when participants judge the length of the elements by touch (Heller, Calcaterra, Burson, & Green, 1997;Heller & Joyner, 1993). Heller and colleagues found that the HVI occurs with touch but that the magnitude of the effect depends on visual experience and stimulus size.…”

“…When T and L figures were presented in a frontoparallel plane, where all exploratory movements are tangential, the bisection effect in the T figure remained, whereas the vertical segments in the L figure were no longer overestimated (Day & Avery, 1970;Deregowski & Ellis, 1972). These works point out the importance of scanning (exploration) methods, spatial reference cues or reference frames, anchors, and so on (for a review, see Gentaz & Hatwell, 2004;Heller & Joyner, 1993;Millar & Al-Attar, 2000). The strength of the illusion was generally found to be similar for sighted and blind participants, ruling out that visual imagery or visual representations are responsible for the haptic illusion.…”

“…An overview of studies of the HVI and its variants-the primary studies used in the present investigation-is given in Table 1. The HVI was first shown for the modality of vision, but it has also been investigated for the modalities of grasping and touch (for a review, see Gentaz & Hatwell, 2004;Heller & Joyner, 1993;Millar & Al-Attar, 2000;Raudsepp & Djupsjöbacka, 2005).…”

Haptic perception: A tutorial

“…For example, curvature perception depends on whether the curvature is convex or concave (van der Horst & , the direction of movement over the surface (Davidson, 1972;Hunter, 1954), the position of the stimulus on the hand (Pont, Kappers, & Koenderink, 1997, 1998, and on shape features other than the judged curvature (Vogels, Kappers, & Koenderink, 1999). Haptic perception of linear extent is affected by the path length, curvature (Sanders & Kappers, 2008), rate of exploration between endpoints (Armstrong & Marks, 1999;Lederman, Klatzky, & Barber, 1985), and other linear elements in the field (Heller & Joyner, 1993).…”

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

“…Day comments that they have been described for a long time [18,66]. Suzuki and Arashida looked at the relative effectiveness of various figures, Müller-Lyer, Oppel-Kundt, Bourdon, Ponzo, Poggendorf, vertical-horizontal, Zöllner, Delboeuf [74], while Heller and Joyner considered the horizontal-vertical effect comparing the behavior blind and sighted people [40]. These effects motivated a significant number of recent studies [77,57,33].…”