How to echolocate
In 1974, the philosopher Thomas Nagel wrote a paper in which he argued that it is impossible for us to know or even accurately imagine how other animals experience the world, because our brain structure is very different from theirs. To illustrate, he wrote about imagining what it’s like to be a bat – the wings, the upside-down sleeping, the piercingly accurate hearing that allows for echolocation – and concluded that while we can imagine doing bat behaviours, we cannot imagine having bat experiences.
E.g. I find it very hard to imagine being this cosy
He definitely had a point. We just can’t know about the subjective experiences of anyone other than ourselves, which means we can’t even answer the question ‘What is it like to be another human being?’
But today, we’re going to talk about one way in which we can know a bit of what it’s like to be a bat (or a dolphin, or a shrew).
You see, it turns out most humans probably can echolocate – we just have to learn how.
What is echolocation, anyway?
Echolocation is not just passively taking in what you hear. It is purposely making a noise in order to explore what’s around you by listening to the echo it makes.
A bat (or a dolphin, or a human) making an echolocation call hears both the noise and the echo. The echo will be subtly different from the original noise – maybe quieter, maybe missing certain pitches depending on what it’s bounced off. The bat/dolphin/human can use those differences and the time it’s taken for the echo to return to figure out information about how far away the bounce happened, what direction, perhaps even whether it bounced off something hard or soft.
This means bats/dolphins/humans use echolocation for the same kind of purposes as vision: exploring distant objects/beings and predicting likely futures such as, “I will walk into that other person if I don’t move left soon.” In fact, when expert human echolocators listen to echoes, brain scans show activity in parts of their brains that are more usually associated with vision.
Of course, hearing can also be used to detect distant objects and beings but, crucially, only if they are making noises. Parked cars, trees, doors, people who haven’t noticed we’re about to walk into them – none of them are likely to alert us to their presence by making a noise.
For humans, echolocation is a good alternative to vision, though it does have drawbacks. It’s much easier to hear echoes bouncing off head-height objects than ground-height objects. It’s more difficult in some conditions than others; the noise of rain or traffic or the muffling effect of snow will all make it harder. Unlike vision, you’re not getting a constant stream of information but something more like a series of snapshots. Though precision of echolocation varies from person to person, it has a far lower precision limit than vision because sound has longer wavelengths than light – so it's like looking at something out of the corner of your eye rather than focusing on it directly. And, until very recently, there’s been no training available, so most people have had to teach themselves or learn informally from someone else.
With all these drawbacks, why use echolocation if vision does the job?
Not everyone can see
Many humans who are expert echolocators have one thing in common – they’re blind.
It’s not clear exactly what proportion of blind people use echolocation, but it’s probably at least one in five. That’s a lot of echolocators! How come?
Well, if you’re a blind person who’s learned to echolocate, the research indicates it’s probably been hugely beneficial for you. (Though do bear in mind this research is based on a pretty small number of people – most studies on expert echolocators have fewer than a dozen participants, and they’re typically people who have good hearing and have been blind from birth or childhood, so there are lots of open questions like “is it as useful for someone who’s lost their sight later in life?” and “how does wearing a hearing aid affect echolocation?”)
Echolocators often find it easier to navigate in unfamiliar places than other blind people. While you might need to walk slower as you’re learning to echolocate, once you become familiar with it, you’re likely to be able to walk through an unfamiliar room with unknown obstacles just as fast as a sighted person using vision.
You don’t have to be echolocating for long to experience these benefits; total beginners start improving even within the first hour. If you train for longer, you’ll continue to see improvements. One of the most extraordinary echolocators I know of is a guy called Ben Underwood, who lost his eyes to cancer at the age of three. He taught himself to echolocate, and he did it so well he was able to skateboard, play football and ride a bike.
Dr Lore Thaler and her research group have been working on echolocation for years. In 2021, they decided they’d learned enough to trial a 10-week training programme with a small group of blind and sighted (but blindfolded) adults of all different ages, from their 20s to their 70s. The training was twice a week for 2-3 hours and involved all kinds of tasks like figuring out which of two objects was bigger and navigating through virtual mazes. No matter the task, people got better at it over the course of the training, though of course some people saw bigger improvements than others. And it carried over into the real world! Three months later, the researchers followed up with the blind participants, who were still using echolocation in their daily lives because it had a positive impact on their mobility, independence, and wellbeing in multiple aspects of their lives. (In another study, Dr Thaler found that blind echolocators have higher salaries than non-echolocators, which suggests it might also provide a general confidence boost that carries over into other areas of your life – like asking for a raise.)
The researchers included some quotes from participants in their report, and this one in particular, from a woman in her forties, touched me because it showed how profoundly it had affected not only her life but the lives of people around her:
“I feel more awake and more alive… I can do more with my children which makes me feel a better parent… My mother is confident to let me go; she has more confidence in me and says that she just leaves me to get on with it; it takes the pressure off her and makes for a much more mature relationship.”
Now that we know how useful echolocating can be, let’s talk about…
How to learn to echolocate
You’re probably going to need your mouth and/or your hands for this
To some extent, this is about figuring out what’s right for you. Different people have different bodies, needs, brains, sensory abilities. However, I hope the tips I’ve gathered from the research in this area will give you some good starting points.
What kind of noise should I make?
Most expert echolocators tend to use high-pitched noises because these are more easily absorbed by what’s around us than low-pitched noises. This might seem counterintuitive, but with echolocation the useful information is what’s missing when the sound comes back to you. You also want a noise that’s easy to make consistently if you do it multiple times in quick succession, but which you can make louder, softer, higher- or lower-pitched if you need to. That means you probably want to use your mouth or your hands, because they’re generally the most dextrous parts of our bodies. (Researchers are now starting to work on tools that generate useful clicks for echolocation, so that might also be an option in a couple of years.)
For near distances – with your mouth
From a pair of studies that compared six different types of mouth and hand noises, your best overall option is probably a click or pop made by pressing your tongue against the top of your mouth just behind your teeth and then pulling it sharply away. If you’re familiar with the drag queen Alyssa Edwards, you’ll know exactly what this noise is – though for echolocation it might be better not to do the Alyssa-style jaw-drop because that could tire out your facial muscles pretty quickly! As well as being fun to do, the tongue pop also has a couple of other advantages: unlike many other mouth sounds it doesn’t interfere with breathing, and it’s easy to triangulate the echoes because your mouth is in a fixed position relative to your ears.
For near distances – with your hands
If you can’t or don’t want to use your mouth, your second-best option is to use your hands. However, the most useful noises require both hands and a decent amount of finger flexibility – which rules them out if you have one hand, arthritis, or even a cup of tea you don’t want to spill. Even if you’re OK on that front, it’s harder to triangulate the echoes than with a tongue click, because the spatial relationship between your hands and your ears isn’t consistent.
Bearing those restrictions in mind, the best option for a high-pitched and easy-to-vary noise made with your hands is something called a knuckle vacuum, which I learned how to do especially for this blog. Basically, make a loose fist with one hand, then using one of the fingers of your other hand, slap it against the ‘valley’ made by two of your fingers of the fist so the tip of your slapping finger lands in the gap between two of the knuckles. If you aim right, you’ll get a sharp sound that sounds similar to a tongue pop.
For further distances – with your hands
Since echolocation based on quiet sounds tends to get less accurate with distance, many echolocators make louder noises when detecting further objects. If the click or the knuckle vacuum isn’t making it far enough to bounce off what you want to know about, hand claps are your friend, but you’ll need to make them much less often because otherwise you won’t be able to hear the echoes over the noise.
Should I move while I’m echolocating?
Yes, if your goal is to use it to navigate in the real world! You might want to echolocate, move, pause, echolocate again, especially when you’re starting out. If and when you feel comfortable moving and echolocating at the same time, you may want to adjust the rate you make your noise to fit the speed you’re moving at. The way the echo changes in different places can tell you a lot about how far ahead something is, what kind of shape it is, what material it’s made of, and whether it’s to your left, right, or straight in front.
Obviously there are safety implications to this if you’re blind, but most blind echolocators also use at least one aid, commonly a long cane. Echolocation and long canes are an absolute dream team for detecting and avoiding obstacles: echolocation for the higher-up stuff, long cane for the stuff on the floor.
If moving your whole body is out of the question in a particular situation – maybe you’re in a field full of rabbit holes? – then moving your head from side to side as you echolocate should also help you get more information about an object, in the same way that if you were using vision you’d gain more information by moving your head to look at it from different angles.
Where can I use echolocation?
You might be thinking that echolocation isn’t useful unless you’re in a quiet environment, but that’s definitely not the case. It can be used both indoors and outdoors, in places with the moderate levels of background noise you get in everyday life. There are limitations on this, ranging from the obvious (next to a loudspeaker at a gig will definitely make echolocation very difficult) to the surprising. Being in a room that’s really well soundproofed can actually make it harder to echolocate.
What should I do if I want to learn more?
Earlier I mentioned Dr Lore Thaler’s echolocation training programme – she’s arguably the world expert in human echolocation. And she’s got a website, which you can access at this link! It has an FAQ that covers much more detail about echolocation, including tips on combining echolocation with mobility aids and for teaching children to echolocate. She also offers free workshops about echolocation which take place at Durham University in the UK.