Where did that noise come from?

The ability to estimate distances to sound sources accurately can be crucial for survival. The investigation carried out under the direction of GSN Member Professor Lutz Wiegrebe reveals that humans can perform this task more efficiently when they are allowed to move. The findings are published in the Proceedings of the National Academy of Sciences (PNAS).

“We humans find it difficult to assess, either visually or acoustically, how far away an object is from us,” Wiegrebe says. “Our visual system makes use, among other things, of the phenomenon of parallax. When we move, the apparent position of an object that is closer to us moves more within our visual field than an object located further away. This relative motion provides information about the relative distance of the two objects. Localization of sounds is particularly challenging when the nature of the sound source is not clearly defined. It is not that difficult for us to estimate our distance from a speeding ambulance when we hear its siren. But when the sound is unknown, we cannot tell whether we are hearing a faint sound close by or a louder sound further away.

As the study shows, humans make readily use of auditory motion parallax associated with self-motion to localize sounds. “However, with practice, it is also possible to improve one’s perception of auditory parallax.” Whether or not other mammals exploit auditory motion parallax is not yet known.

For more information on Lutz Wiegrebe’s research, see:

• Sizing up spaces by ear (01.25.2017)
• The neural basis of vocal learning (03.22.2016)
• No way out (03.19.2015)

Article source: LMU News