Some people have the incredible ability to determine the position of "silent" objects simply through echoes, and new research suggests this talent is based on good high-pitched hearing in both ears.
The findings conclusively demonstrate how some people with vision disabilities or blindness could use echoes to help them navigate the world, the University of Southampton reported.
"We know that hearing echoes is very important in daily life for some blind people. Hearing loss, such as associated with getting older, usually reduces hearing at high frequencies in both ears. Some people can develop deafness in one ear. We wanted to get some insight into how much those particular forms of hearing loss might affect users of echoes to locate objects: our results suggest they would struggle," said Daniel Rowan, lead author of the study.
The researchers looked at a group of sighted and blind people who were asked if an object was to the left or right of them. The team used a "virtual auditory space" technique that allowed them to remove audio and non-audio clues to the location of the object (a flat MDF board) that were not related to echoes. They found people who proved to have good high-frequency hearing in both ears could accurately determine the location of the test object.
"Hearing aid services tend to focus on how well a person can hear speech. Our research indicates that those services also need to take into account whether someone needs to hear echoes in their daily life. For example, they might need hearing aids in both ears, despite the emerging trend in some parts of the country to only fit one," Rowan said.
In the near future, a web-app will be launched that will allow the general public to test out some of these experiments themselves and see if they can locate objects "like a bat."
The findings were published in a recent edition of the journal Hearing Research.