The philosopher Thomas Nagel posed, and prematurely answered, a question that has vexed philosophers and animal scientists ever since: what is it like to be a bat? A mammal not so very distantly related to us (our nearest living non-primate relatives, in fact), yet inhabiting a perceptual world so alien that, Nagel suggests, we cannot possibly conceive it.
Nagel’s bat example exerted a powerful grip on the imaginations of those thinkers who came after him, and the questions it threw up risked opening up a gulf of uncertainty about our capacity not only to understand bats, but any other animal, including other humans. The trouble is Thomas Nagel was wrong from the outset, and we can thank David Kish for proving it.
Seeing with your ears.
David Kish is one of the pioneers of human echolocation. Blind from the age of two, David learnt to spatially orient himself not only by using sounds from animate objects, but by interpreting how his own tongue clicks reverberated off the inanimate objects around him – a human approximation of the echolocation used by bats, dolphins and whales.
David went on to formally studied the neurology and physiology of human echolocation, and now teaches echolocation to other blind people. He is also seeking to develop prosthetic devices which will augment his and other blind people’s echolocating abilities.
One of the most gifted practitioners of human echolocation was Ben Underwood, a gifted natural athlete who also spontaneously developed an echolocating tongue-click technique as a young child. Ben got around without a cane his whole life, and unlike David Kish and his other students, who maintain the cautious upright carriage we normally associate with the blind, Ben maintained the loose-limbed confidence of an agile fully-sighted youth. Of all the best known exponents of echolocation, Ben was closest to fulfilling the profile of the blind acrobat, Daredevil, of Marvel Comics, fame. Tragically, by the time Marvel Comics’ Stan Lee came do explore human echolocation in his TV show on real life superhumans, Ben had already passed away. He succumbed at age 16 to the same cancer which originally took his eyes.
While it seems that the rudiments of echolocation can even be taught to sighted people, a refined echolocation ability is unlikely to be teachable to people with adult onset blindness. David and Ben were probably young enough to recruit much of the visual parts of their brain (e.g. the occipital lobe) to spatially interpret auditory information.
Seeing with your skin!
But sound is not the only sense that has been recruited to conquer human blindness. Prostheses have been developed which translate images from a head mounted video camera into tactile signals which can be received by the skin on your back, stomach or even tongue! Essentially these signals are interpreted in the same way we recognize letters or numbers traced with a finger on our back in a child’s game.
In short, it does not take an impossible leap of imagination to wonder what it is like to be a bat, or a dolphin, or some creature which navigate the physical world using some totally alien sense like the electroception of sharks or the magnetoception of certain birds.
The blindspots of echolocation
There are however some limits to the insight we can gain into the experience of how it feels to be a bat – and to this more limited degree Nagel was on to something.
Male subjects with adult-onset blindness who were shown pornographic images through sensory substitution devices were totally unmoved by them, and we might expect the same to be true of human echolocators encountering encountering a three-dimensional pornographic images like, say, the statues in South Korea’s Loveland themepark.
The intrinsic aesthetic appeal that evolution has bequeathed us when seeing certain curves, certain hues, certain wavelengths of light is no longer available when we interpret these phenomena through unconventional senses. In this important sense, the medium really is the message. The raw emotion of some visual experiences is bound up with the physiology of the eyes, and our longstanding evolutionary dependence on them.
Indeed, all the aesthetics of human pleasure and displeasure are ultimately derived from emotional signals evolution developed as a shorthand to optimize the survival of humans and our ancestors over millions of years.
As humans have increasingly freed ourselves from the relentless quest for pure survival, we have made the world in the image of that evolutionary design. We devote much of our time and energy to creating and experiencing supernormal stimuli – human artefacts which exaggerate, caricature, combine and refine the natural stimuli which nature designed us to enjoy.
It is no surprise that as human prosperity has grown, we have increasingly cultivated our appetites for art, entertainment, cuisine, nor is it surprising that we have created new dangers for ourselves in terms of super-calorific foods, intoxicants, narcotics and to supernormal sexual stimuli. What is more surprising, perhaps, is the extent to which we ignore our most basic needs as a species which evolved to thrive on the warm open savannah of Pleistocene Africa and Europe, i.e. our appetite for open, uncluttered space; for warm, salubrious air; for sunlight; for greenery; for rivers and streams; for the soothing sounds of birdsong and the wind in the trees. All the things, in short, which give us peace.
All too often our ongoing pursuit of prosperity places us in noisy, open-plan offices, with windows looking out onto brick walls, and relentlessly grey urban environments of unpunctuated concrete and bitumen bound to make us restless and discomfitted. Strangely, despite the increasing material prosperity of the middle classes, it remains the rich who seem to maintain a monopoly on beautiful outdoor spaces, be they natural or cultivated.
To the extent to which we remain unattuned to our own evolved needs, we are very unlikely to appropriately consider those of non-human animals with evolutionary histories or ecological niches very different to our own. As for bats, we may never know the specific emotional qualities the frequency of certain sounds will have to them, such as the echo of their own ultrasonic squeak off a nearby tasty insect. But we have a lot of common emotional hardware, and visual analogues aplenty which might guide us in knowing roughly how this feels. In one of his last interviews Ben, described a new echolocating insight he’d only recently acquired in his pioneering mastery of the technique: that the reverberation of sound off humans was exactly the same at the sound of water. Perhaps that is how we appear to bats as well.