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PERCEPTION Our useful inability to see reality There’s some deviant thinking behind perception, discovers Douwe Draaisma.

nlightenment thinker John Locke deafness — with compensation. Lotto men- (1632–1704) held that the human tions, for instance, the late Ben Underwood, mind is a blank slate at birth, ready to a blind US teenager who used echolocation, Ebe written over by sensory experience. Over clicking his tongue and using the echoes of

the centuries, this idea of information flow- the sound to navigate, and even to cycle and SUREN MANVELYAN ing ‘outside in’ has lost much of its appeal, play sports. with experiments making it clear that per- Lotto’s idea that perception includes a ception involves dozens of mechanisms, multitude of assumptions, built-in or learnt, actively shaping stimuli rather than passively allows him to take on board a range of sub- receiving them. jects not usually associated with the topic. In Deviate, neuroscientist Beau Lotto For instance, confirmation bias — notic- presents a complete reversal of the Lockean ing evidence that affirms one’s world view, stance. To him, it is the human mind that but disregarding contradictory evidence imposes meaning on our perceptions: the — is conventionally taken to be a cogni- true blank slate is the outside world. Even tive phenomenon. Like hindsight bias, it more provocative is his argument that we contributes to preconceived ideas that keep operate with versions of reality that have us locked into a narrow perspective on our literally nothing to do with what is ‘out personal and social reality. This is why the there’ in a physical sense. In an entertain- book is called Deviate, and Lotto has inspir- ing series of analyses, demonstrations and ing things to say about discoveries and acts reflections, he drives home the point that of creativity resulting from ‘deviant’ ways of perception, broadly taken, is not what our thinking. eyes and ears tell us; it is what our brain Deciphering the Rosetta Stone is a case makes us see and hear. in point. Comparing the stone’s trilingual This is a radical philosophy of percep- scripts in the nineteenth century, Jean- tion. It raises an intriguing question about François Champollion unlocked the code the evolutionary history of our perceptual of Egyptian hieroglyphs by hypothesizing apparatus. If evolution is truly “the most that they were not symbolic characters rep- rigorous, exhaustive research and develop- resenting concepts, but instead referred to ment and product-testing process on our Seeing isn’t necessarily believing. the phonetic sounds of a spoken language planet”, as Lotto has it, then to survive at (A. Robinson Nature 483, 27–28; 2012). all, surely our senses must have given our points out that for With Lotto’s pervasive evolutionary per- ancestors and us a trustworthy representa- each neural connec- spective comes a lot of fight or flight, adapt tion of reality? Lotto’s answer is an emphatic tion that projects or die, and escaping from predators. It leaves no: “We don’t see reality — we only see what information from the reader wondering whether there could was useful to see in the past.” Much like a the eyes to the pri- be any perception — aesthetic pleasures such London Underground map, our perceptual mary visual fields in as listening to music — not in the service of brain doesn’t offer an accurate spatial rep- the occipital lobes at survival. At times, Lotto seems to overstate resentation; rather, it helps us to navigate in the back of the brain, his case, for instance when he writes that Igor a safe and efficient way. there are ten con- Stravinsky reshaped “the cortex of culture” So, visual illusions — such as the Moon nections back from Deviate: The by composing the ballet The Rite of Spring. looking larger when it is closer to the hori- the brain to the eyes. Science of Seeing Towards the end, Deviate begins to take zon — aren’t really illusions if our perceptual Moreover, the neural Differently an unusually broad view of perception, apparatus didn’t evolve to see actual spatial networks that make BEAU LOTTO including discussions of the Ebola epidemic, relationships. Tellingly, machines devised to sense of what we ‘see’ Hachette: 2017. religion, the financial crisis, the salutary recognize visual patterns are also suscepti- are fed by a relatively effects of living abroad, government policy ble to illusions when they are programmed small stream of information from the eyes. towards universities and the need for new in a way that emulates the structure of the About 90% comes from other parts of concepts of leadership. Lotto’s neuroscience human brain. the brain, allowing us to recognize faces, tends to the expansive. Still, his discussions Deviate is not your conventional hand- identify danger or read a sentence such as are balanced by many astute observations, book of perception. It has little on the ‘W at ar ou rea in ?’ despite the omitted such as: “Our species has been so successful anatomy of the eye or mechanisms of letters. That you probably didn’t read that not in spite of our inability to see reality but hearing. The senses as ‘What are you dreaming?’ is the result because of it.” ■ are like the keyboard NATURE.COM of priming your attention to a context of of a computer: they For more on science reading. What enters the eye is often an Douwe Draaisma is professor of the history provide access, and in culture see: insignificant part of the story. of psychology at the University of Groningen the real job is done nature.com/ These networks provide the brain with in the Netherlands. elsewhere. Lotto booksandarts flexibility and — in cases of blindness or e-mail: [email protected]

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