The Role of Pictorial Convention in Haptic Picture Perception

Abstract

An investigation of tactile picture perception is reported. Blindfolded sighted subjects explored either 'line drawings' or 'textured' tactile pictures produced on Zytex swell paper. All pictures were 'two-dimensional', that is they depicted only one object face and so did not represent a third dimension. Both picture sets represented the same objects. Results revealed that the textured pictures, in which solid surfaces of depicted objects were uniformly textured, were recognised more often than tactile line drawings, in which surfaces of objects were simply bounded by lines. There were no significant correlations between imagery ability (visual, cutaneous, or kinaesthetic) and picture recognition success. Texture may be a form of 'uniform connectedness' (Palmer and Rock 1994 Psychonomic Bulletin & Review 1 29-55) or 'common region' (Palmer 1992 Cognitive Psychology 24 436-447), highlighting the global characteristics of stimuli. We argue that textured pictures may encourage the haptic system to take a more globally oriented approach to tactile picture perception, benefiting recognition.

Look what I have felt: Unidentified haptic line drawings are identified after sketching

“…Thus, the cutaneous information is predominantly used for movement control and not for identification. Along the same lines, Thompson, Chronicle, and Collins (2003) found that completely embossed drawings are better identified than raised line drawings. An embossed surface guides the finger more easily along the picture than only a line, thus relieving the observer partly from the exploration task.…”

Angle Discrimination in Raised-Line Drawings

“…Numerous investigators have reported on various aspects of the recognition process, such as the influence of visual status (Heller 1989;Lederman et al 1990), the benefit of categorical information (Heller et al 1996), and the influence of depiction technique (Thompson et al 2003). However, little is known about the perceptual performance subserving this recognition process.…”

“…This hypothesis is tested by looking at the discriminability of convex and concave angles. Furthermore, research into haptic picture perception showed that pictures consisting of raised surfaces are better recognised than pictures consisting of raised lines (Thompson et al 2003). Finding lower discrimination thresholds for raised-surfaceboundary angles could give us a better understanding of the recognition improvement found by Thompson et al (2003).…”

The Influence of Picture Size on Recognition and Exploratory Behaviour in Raised-Line Drawings

“…In contrast, Symmons and Richardson (2000) found that observers spontaneously explored raisedline drawings with a single finger. In attempting to increase the recognisability of raised-line drawings, Thompson et al (2003) found that`filled' drawings (the whole region between the lines is embossed instead of only the lines themselves) are recognised more accurately than raised-line stimuli.…”