humans can learn to discriminate the sizes & orientations of nearby objects by making clicking noises with their mouths & listening to the echoes. it takes many hours of training, but performance can be remarkably good  

original article: Norman et al., 2021 (Public Library of Science ONE), reported in: The Daily Mail by Sam Tonkin on 2nd June 2021

this story was in episode 12 #bat #echo #sound #perception #blindness

the error bar says

philosophers used to wonder what it was like to be a bat

but instead of just philosophising they should have got out of their armchairs & into a laboratory in Durham, UK, where psychologists trained sighted & blind adults to be bats

well, not quite to be bats, but instead to use their mouths & ears to perceive the size of discs, the orientation of rectangular boards & to navigate a virtual maze

this was an intensive task, with three researchers training 26 volunteers on 50 hours each of practice over 10 weeks to produce mouth clicking sounds & listen for the echoes from nearby objects

as reported in the Daily Mail, the humans learnt to perform rather well, increasing their accuracy, decreasing the time taken & increasing the distance from which they could accurately perceive the objects in front of them. after 10 weeks, healthy young sighted people became almost as good as expert blind echolocators

can humans really echolocate?


despite the unlikely-sounding story, some initial skepticism from your host & the Daily Mail printing the brain the wrong way around, this is a serious study from a research group that has studied this serious topic seriously for a long time

each of the tasks that the volunteers were trained on - size & orientation discrimination, virtual & real navigation - was practised about 20 times a day, two days a week, for 10 weeks

the methods used were good: volunteers were inside a sound-attenuated chamber & blindfolded; the task forced participants to say which of two things - which they couldn't see - was larger, or in which orientation; the researchers included controls for incidental learning & spent a long time with each participant

the article itself is a majestic 34 pages long, highly detailed & fully analysed; the data & results are very clear

i suspect that even philosophers would like this study


trapped in a sound-attenuated chamber for 50 hours, human volunteers can learn to discriminate the size & orientation of objects by mouth-clicking & listening to the echoes


The Daily Mail: fact - scientific story reported well