Document Detail


Human echolocation: Blind and sighted persons' ability to detect sounds recorded in the presence of a reflecting object.
MedLine Citation:
PMID:  20514997     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Research suggests that blind people are superior to sighted in echolocation, but systematic psychoacoustic studies on environmental conditions such as distance to objects, signal duration, and reverberation are lacking. Therefore, two experiments were conducted. Noise bursts of 5, 50, or 500 ms were reproduced by a loudspeaker on an artificial manikin in an ordinary room and in an anechoic chamber. The manikin recorded the sounds binaurally in the presence and absence of a reflecting 1.5-mm thick aluminium disk, 0.5 m in diameter, placed in front, at distances of 0.5 to 5 m. These recordings were later presented to ten visually handicapped and ten sighted people, 30-62 years old, using a 2AFC paradigm with feedback. The task was to detect which of two sounds that contained the reflecting object. The blind performed better than the sighted participants. All performed well with the object at <2 m distance. Detection increased with longer signal durations. Performance was slightly better in the ordinary room than in the anechoic chamber. A supplementary experiment on the two best blind persons showed that their superior performance at distances > 2 m was not by chance. Detection thresholds showed that blind participants could detect the object at longer distances in the conference room than in the anechoic chamber, when using the longer-duration sounds and also as compared to the sighted people. Audiometric tests suggest that equal hearing in both ears is important for echolocation. Possible echolocation mechanisms are discussed.
Authors:
Bo N Schenkman; Mats E Nilsson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Perception     Volume:  39     ISSN:  0301-0066     ISO Abbreviation:  Perception     Publication Date:  2010  
Date Detail:
Created Date:  2010-06-02     Completed Date:  2010-08-31     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0372307     Medline TA:  Perception     Country:  England    
Other Details:
Languages:  eng     Pagination:  483-501     Citation Subset:  IM    
Affiliation:
Blekinge Institute of Technology, Box 520, SE-372 25 Ronneby, Sweden. bo.schenkman@bth.se
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MeSH Terms
Descriptor/Qualifier:
Adult
Analysis of Variance
Audiometry
Blindness*
Female
Humans
Male
Middle Aged
Sound Localization / physiology*
Space Perception / physiology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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