[Nfbf-l] New study finds blind people have the potential to use their 'inner bat' to locate objects.

[Alan Dicey]

New study finds blind people have the potential to use their 'inner bat' to 
locate objects.
New research from the University of Southampton has shown that blind and 
visually impaired people have the potential to use echolocation, similar to 
that used by bats and dolphins, to determine the location of an object.
The study, which is published in the journal Hearing Research, examined how 
hearing, and particularly the hearing of echoes, could help blind people 
with spatial awareness and navigation. The study also examined the possible 
effects of hearing impairment and how to optimise echolocation ability in 
order to help improve the independence and quality of life of people with 
visual impairments.
Researchers from the University of Southampton's Institute of Sound and 
Vibration Research (ISVR) and University of Cyprus conducted a series of 
experiments with sighted and blind human listeners, using a 'virtual 
auditory space' technique, to investigate the effects of the distance and 
orientation of a reflective object on ability to identify the 
right-versus-left position of the object. They used sounds with different 
bandwidths and durations (from 10-400 milliseconds) as well as various audio 
manipulations to investigate which aspects of the sounds were important. The 
virtual auditory space, which was created in ISVR's anechoic chamber, 
allowed researchers to remove positional clues unrelated to echoes, such as 
footsteps and the placement of an object, and to manipulate the sounds in 
ways that wouldn't be possible otherwise (e.g. get rid of the emission and 
present the echo only).
Dr Daniel Rowan, Lecturer in Audiology in ISVR and lead author of the study, 
says: "We wanted to determine unambiguously whether blind people, and 
perhaps even sighted people, can use echoes from an object to determine 
roughly where the object is located. We also wanted to figure out what 
factors facilitate and restrict people's abilities to use echoes for this 
purpose in order to know how to enhance ability in the real world."
The results showed that both sighted and blind people with good hearing, 
even if completely inexperienced with echolocation, showed the potential to 
use echoes to tell where objects are. The researchers also found that 
hearing high-frequency sounds (above 2 kHz) is required for good 
performance, and so common forms of hearing impairment will probably cause 
major problems.
Dr Daniel Rowan adds: "Some people are better at this than others, and being 
blind doesn't automatically confer good echolocation ability, though we 
don't yet know why. Nevertheless, ability probably gets even better with 
extensive experience and feedback.
"We also found that our ability to use echoes to locate an object gets 
rapidly worse with increasing distance from the object, especially when the 
object is not directly facing us. While our experiments purposely removed 
any influence of head movement, doing so might help extend ability to 
farther distances.
Furthermore, some echo-producing sounds are better for determining where an 
object is than others, and the best sounds for locating an object probably 
aren't the same as for detecting the object or determining what, and how far 
away, the object is."
The knowledge gained from this study will help researchers to develop 
training programmes and assistive devices for blind people and sighted 
people in low-vision situations. The team is also extending their research 
to investigate finding of objects in three-dimensional space and why some 
blind people seem to be able to outperform others, including sighted people.
The research was partly funded by a Research Council UK Basic Technology 
Programme grant to the Bio-Inspired Acoustical Systems project and 
Engineering and Physical Sciences Research Council (EPSRC) Vacation 
Bursaries.

Notes for editors:
1. The paper Rowan, D., Papadopoulos, T., Edwards, D., Holmes, H., 
Hollingdale, A., Evans, L., & Allen, R. (2013) 'Identification of the 
lateral position of a virtual object based on echoes by humans' is published 
in Hearing research, 300, 56-65. doi:10.1016/j.heares.2013.03.005

Source URL:
http://www.eurekalert.org/pub_releases/2013-05/uos-nsf052013.php

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