A blind human expert echolocator shows size constancy for objects perceived by echoes

Milne, J.L.; Anello, M.; Goodale, M.A.; Thaler, L.

Abstract

Some blind humans make clicking noises with their mouth and use the reflected echoes to perceive objects and surfaces. This technique can operate as a crude substitute for vision, allowing human echolocators to perceive silent, distal objects. Here, we tested if echolocation would, like vision, show size constancy. To investigate this, we asked a blind expert echolocator (EE) to echolocate objects of different physical sizes presented at different distances. The EE consistently identified the true physical size of the objects independent of distance. In contrast, blind and blindfolded sighted controls did not show size constancy, even when encouraged to use mouth clicks, claps, or other signals. These findings suggest that size constancy is not a purely visual phenomenon, but that it can operate via an auditory-based substitute for vision, such as human echolocation.

Citation

Milne, J., Anello, M., Goodale, M., & Thaler, L. (2015). A blind human expert echolocator shows size constancy for objects perceived by echoes. Neurocase: The Neural Basis of Cognition, 21(4), 465-470. https://doi.org/10.1080/13554794.2014.922994

• Journal Article Type: Article
• Acceptance Date: May 6, 2014
• Online Publication Date: May 29, 2014
• Publication Date: May 1, 2015
• Deposit Date: Mar 4, 2014
• Publicly Available Date: Sep 8, 2014
• Journal: Neurocase: The Neural Basis of Cognition
• Print ISSN: 1355-4794
• Electronic ISSN: 1465-3656
• Publisher: Taylor and Francis Group
• Peer Reviewed: Peer Reviewed
• Volume: 21
• Issue: 4
• Pages: 465-470
• DOI: https://doi.org/10.1080/13554794.2014.922994
• Keywords: Blindness, Human echolocation, Size constancy, Vision, Multisensory.
• Public URL: https://durham-repository.worktribe.com/output/1436343