Solid shape discrimination from vision and haptics: natural objects (Capsicum annuum) and Gibson’s “feelies”

• Published in: Experimental brain research 2012-10, Vol.222 (3), p.321-332
• Main Authors: Norman, J. Farley, Phillips, Flip, Holmin, Jessica S., Norman, Hideko F., Beers, Amanda M., Boswell, Alexandria M., Cheeseman, Jacob R., Stethen, Angela G., Ronning, Cecilia
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Applied physiology; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Capsicum annuum; Cues; Discrimination; Discrimination (Psychology) - physiology; Experiments; Female; Haptics; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Male; Medical sciences; Neurology; Neurosciences; Ophthalmology; Orientation; Pattern Recognition, Visual - physiology; Photic Stimulation; Reaction Time; Recognition (Psychology) - physiology; Research Article; Touch - physiology; Touch Perception - physiology; Transports. Aerospace. Diving. Altitude; Vision; Vision disorders; Visual discrimination; Young Adult
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/s00221-012-3220-7

A set of three experiments evaluated 96 participants’ ability to visually and haptically discriminate solid object shape. In the past, some researchers have found haptic shape discrimination to be substantially inferior to visual shape discrimination, while other researchers have found haptics and vision to be essentially equivalent. A primary goal of the present study was to understand these discrepant past findings and to determine the true capabilities of the haptic system. All experiments used the same task (same vs. different shape discrimination) and stimulus objects (James Gibson’s “feelies” and a set of naturally shaped objects—bell peppers). However, the methodology varied across experiments. Experiment 1 used random 3-dimensional (3-D) orientations of the stimulus objects, and the conditions were full-cue (active manipulation of objects and rotation of the visual objects in depth). Experiment 2 restricted the 3-D orientations of the stimulus objects and limited the haptic and visual information available to the participants. Experiment 3 compared restricted and full-cue conditions using random 3-D orientations. We replicated both previous findings in the current study. When we restricted visual and haptic information (and placed the stimulus objects in the same orientation on every trial), the participants’ visual performance was superior to that obtained for haptics (replicating the earlier findings of Davidson et al. in Percept Psychophys 15(3):539–543, 1974 ). When the circumstances resembled those of ordinary life (e.g., participants able to actively manipulate objects and see them from a variety of perspectives), we found no significant difference between visual and haptic solid shape discrimination.