Novel research conducted by scientists from Durham University, University of Birmingham, and Eindhoven University of Technology have discovered for the first time that human echolocators have better acuity in localising a target from 45° off to the side as compared to from straight ahead at 0°.
The researchers tested echo-localisation abilities of nine blind adult human experts who use this skill on a daily basis.
They discovered that echolocation performance is drastically improved at 45° where the participants can better locate targets based on echoes coming from sideways.
Their findings, which was published in the journal Psychological Science, indicate that human echolocation and human regular spatial hearing might be governed by different principles as regular hearing is best from straight ahead at 0° and gets worse as targets move further to the side.
The researchers point out that human echolocation and regular hearing may rely on different acoustic cues, and that human spatial hearing has more facets than previously thought.
The researchers also characterised and analysed the clicking behaviour of the participants and found that participants made quieter clicks when they receive stronger echo signals coming from sideways at 45° angle.
Lead author of the paper, Dr Lore Thaler of Durham University, said: ‘There is still a lot to discover about human echolocation, and about human perceptual abilities more generally. Our findings show that there are facets of human spatial hearing that we did not know before.’
The researchers further established that better human echo-localisation away from straight ahead is consistent with what has been observed in bats.
This is surprising because bats possess anatomical and neural specialisations for echolocation, which humans do not have. To nonetheless find such behavioural similarity suggests that both humans and bats may have similar sensing strategies.
The findings shed new light on human echolocation capabilities that provide more details and useful guidance for echolocation instructors and new users where they can turn their head away to locate objects and targets more accurately.
