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Posts Tagged ‘Diane Ackerman’

14 NOVEMBER, 2014

Diane Ackerman on What Working at a Suicide Prevention Hotline Taught Her about the Human Spirit

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“Choice is a signature of our species. We choose to live, sometimes we choose our own death, but most of the time we make choices just to prove choice is possible. Above all else, we value the right to choose one’s destiny.”

“How are we so optimistic, so careful not to trip and yet do trip, and then get up and say OK?” Maira Kalman pondered in her visual philosophy. Such is the magnificent resilience of the human spirit. Our culture is haunted by the unholy ghost of suicide; those who succumb to it are mercilessly judged by the media and those who stay behind are at risk of contagion. How, then, do we help those on the brink of self-destruction “get up and say OK?” And what does that act of help reveal about our own trials and triumphs as we learn to be OK?

That’s precisely what Diane Ackerman explores in the gorgeous essay “A Slender Thread” in the anthology The Impossible Will Take a Little While: Perseverance and Hope in Troubled Times (public library | IndieBound), adapted from her altogether sublime 1998 book A Slender Thread: Rediscovering Hope at the Heart of Crisis (public library | IndieBound), which recounts her time working as a volunteer crisis counselor at a suicide prevention hotline, performing a “slow tango of life and death” that demands of its dancers impossible “grace and cunning.”

Ackerman — scientific sorceress of the senses and supreme historian of the human heart — marvels at the humbling, uniquely human notion of the very concept of a suicide prevention hotline:

We use only a voice and a set of ears, somehow tied to the heart and brain, but it feels like mountaineering with someone who has fallen, a dangling person whose hands you are gripping in your own.

Ackerman recalls one particularly poignant call, with Louise — a frequent caller with “many talents, a lively mind, a quirky and unusual point of view, and a generous heart” — whom she had reeled back from the brink of suicide many times before. Louise’s anguish, like that of many on the downward spiral of the psyche, stems from feeling, as Ackerman puts it, bereft of choices. (Which is why Kerkhof’s pioneering suicide-prevention technique is so effective both in clinical contexts and in controlling our everyday worries.) Ackerman reflects on this uniquely human dance with possibility:

Choice is a signature of our species. We choose to live, sometimes we choose our own death, but most of the time we make choices just to prove choice is possible. Above all else, we value the right to choose one’s destiny. The very young and some lucky few may find their days opening one onto another like a set of ornate doors, but most people make an unconscious vow each morning to get through the day’s stresses and labors intact, without becoming overwhelmed or wishing to escape into death. Everybody has thought about suicide, or knows somebody who committed suicide, and then felt “pushed another inch, and it could have been me.” As Emile Zola once said, some mornings you first have to swallow your toad of disgust before you can get on with the day. We choose to live. But suicidal people have tunnel vision—no other choice seems possible. A counselor’s job is to put windows and doors in that tunnel.

Talking to Louise, Ackerman contemplates the enormous and vulnerable and terrifying responsibility of the crisis counselor as a torchbearer of luminous choice amid the darkness of the tunnel:

Every call with Louise has seemed this dire, a last call for help, and she has survived. But suppose tonight is the exception, suppose this is the last of last times? What is different tonight? I’m not sure. Then it dawns on me. Something small. I’m frightened by how often she has been using the word “only,” a word tight as a noose.

Assuring Louise that she would stay with her, Ackerman flickers a sidewise beam on the other meaning of “only” — that of the lonesome one, gripped with our civilizational anxiety of being alone:

So often loneliness comes from being out of touch with parts of oneself. We go searching for those parts in other people, but there’s a difference between feeling separate from others and separate from oneself.

When Louise laments her own weakness, Ackerman invokes her acts of everyday heroism, shared during previous calls — like volunteering during the flood, “filling sandbags and making sandwiches” for the victims. “Broaden the perspective,” Ackerman writes. “The hardest job when someone is depressed.”

Because something feels different about the call — because Ackerman feels the tar-thick darkness of that particular tunnel — she alerts the police while on the line with Louise, who had made her promise not to bring in the authorities. When they arrive — faster than expected — Louise swells with the rage of betrayal, screams at Ackerman, calls her a liar, hangs up. Ackerman loses Louise — loses the call, that is, which holds the grim possibility of losing the life. She writes:

Knowing and not knowing about callers, that’s what gets to me. My chest feels rigid as a boat hull, my ribs tense. Taking a large breath and letting it out slowly, I press my open palms against my face, rub the eyebrows, then the cheekbones and jaw, and laugh. Not a ha-ha laugh, a small sardonic one, the kind we save for the ridiculous, as I catch myself slipping into a familiar trap. I did fine. I did the best I could. Maybe the best anyone could tonight.

Ackerman circles back to the question of choice, so human and so riddled with perplexity:

Helping Louise survive is always an ordeal. Tonight she sounded even more determined and death bound than usual. It was the right choice. I think. Maybe. On the write-up sheet, under “Caller,” I write “Louise,” put the letter “H” for “high” in the box marked “suicide risk,” attach a yellow Lethality Assessment sheet, and add a few details of the call. Pressing my fingertips to my face, I push again on the brow bones, as if I could rearrange them, but they ache from a place I can’t reach with my hands.

A few weeks after that fateful call with Louise, the Crisis Center received a postcard from her, thanking the counselor — always anonymous, as was Ackerman to her caller — for, essentially, illuminating her tunnel. After the police had taken her to the emergency room, she had checked herself into a psychiatric hospital in Pennsylvania for three weeks of “palatial bedlam.” Upon returning home, she had found a new job to replace the one she had lost and begun volunteering again, reporting that she was finally “in a good place.”

Ackerman’s closing words emanate far beyond the grimly glimmering grace of suicide prevention and into the broader and immeasurable beauty of asking for and receiving help. Beholding that postcard in disbelief, she writes:

She blesses the soul who “took my life in her hands that night,” thanks us all for our good work, is just writing “to let you know what happened — I bet you don’t hear that very often.” We don’t.

People take our lives in their hands all the time — parents, mentors, lovers, teachers, patrons. How often do they hear from us?

The Impossible Will Take a Little While, which also gave us Victoria Safford on what it really means to “live our mission,” is a soul-raising read in its totality. Complement this particular excerpt with Bukowski’s beautiful letter of gratitude to the man who changed his life, then revisit Ackerman on what the future of robots reveals about the human condition and a fascinating look at how the psychology of suicide prevention can help us control our everyday worries.

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06 OCTOBER, 2014

What the Future of Robots Reveals About the Human Condition

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“I find it touchingly poetic to think that as our technology grows more advanced, we may grow more human.”

In the most memorable scene from the cinematic adaptation of Carl Sagan’s novel Contact, Jodi Foster’s character — modeled after real-life astronomer and alien hunter Jill Tarter — beholds the uncontainable wonder of the cosmos, which she has been tasked with conveying to humanity, and gasps: “They should’ve sent a poet!”

To tell humanity its own story is a task no less herculean, and at last we have a poet — Sagan’s favorite poet, no less — to marry science and wonder. Science storyteller and historian Diane Ackerman, of course, isn’t only a poet — though Sagan did send her spectacular scientifically accurate verses for the planets to Timothy Leary in prison. For the past four decades, she has been bridging science and the humanities in extraordinary explorations of everything from the science of the senses to the natural history of love. In The Human Age: The World Shaped By Us (public library | IndieBound), Ackerman traces how we got to where we are — a perpetually forward-leaning species living in a remarkable era full of technological wonders most of which didn’t exist a mere two centuries ago — when “only moments before, in geological time, we were speechless shadows on the savanna.”

With bewitchingly lyrical language, Ackerman paints the backdrop of our explosive evolution and its yin-yang of achievement and annihilation:

Humans have always been hopped-up, restless, busy bodies. During the past 11,700 years, a mere blink of time since the glaciers retreated at the end of the last ice age, we invented the pearls of Agriculture, Writing, and Science. We traveled in all directions, followed the long hands of rivers, crossed snow kingdoms, scaled dizzying clefts and gorges, trekked to remote islands and the poles, plunged to ocean depths haunted by fish lit like luminarias and jellies with golden eyes. Under a worship of stars, we trimmed fires and strung lanterns all across the darkness. We framed Oz-like cities, voyaged off our home planet, and golfed on the moon. We dreamt up a wizardry of industrial and medical marvels. We may not have shuffled the continents, but we’ve erased and redrawn their outlines with cities, agriculture, and climate change. We’ve blocked and rerouted rivers, depositing thick sediments of new land. We’ve leveled forests, scraped and paved the earth. We’ve subdued 75 percent of the land surface — preserving some pockets as “wilderness,” denaturing vast tracts for our businesses and homes, and homogenizing a third of the world’s ice-free land through farming. We’ve lopped off the tops of mountains to dig craters and quarries for mining. It’s as if aliens appeared with megamallets and laser chisels and started resculpting every continent to better suit them. We’ve turned the landscape into another form of architecture; we’ve made the planet our sandbox.

But Ackerman is a techno-utopian at heart. Noting that we’ve altered our relationship with the natural world “radically, irreversibly, but by no means all for the bad,” she adds:

Our relationship with nature is evolving, rapidly but incrementally, and at times so subtly that we don’t perceive the sonic booms, literally or metaphorically. As we’re redefining our perception of the world surrounding us, and the world inside of us, we’re revising our fundamental ideas about exactly what it means to be human, and also what we deem “natural.”

Nowhere does this revolutionary reframing come more alive than in a chapter poetically titled “When Robots Weep, Who Will Comfort Them?” Ackerman’s exploration of the implications of artificial intelligence is at first necessarily discomfiting, then productively perplexing, then assuringly optimistic. She writes:

It’s an Anthropocene magic trick, this extension of our digital selves over the Internet, far enough to reach other people, animals, plants, interplanetary crews, extraterrestrial visitors, the planet’s Google-mapped landscapes, and our habitats and possessions. If we can revive extinct life forms, create analog worlds, and weave new webs of communication — what about new webs of life? Why not synthetic life forms that can sense, feel, remember, and go through Darwinian evolution?

Illustration from 'Alice in Quantumland' by Robert Gilmore. Click image for more.

To probe the furthest fringes of this question, Ackerman visits the pioneering Cornell University roboticist Hod Lipson, whose lab is working on the development of a new self-aware species, Robot sapiens. Ackerman explains the implications, nothing short of existential:

Our own lineage branched off many times from our apelike ancestors, and so will the flowering, subdividing lineage of robots, which perhaps needs its own Linnaean classification system. The first branch in robot evolution could split between AI and AL — artificial intelligence and artificial life. Lipson stands right at that fork in that road, whose path he’s famous for helping to divine and explore in one of the great digital adventures of our age. It’s the ultimate challenge, in terms of engineering, in terms of creation.

If this sounds a little sci-fi, Ackerman points out that the very notion of Robot sapiens is predicated on one of the most undeniable forces Earth has ever known, that of evolution — Lipson’s work, then, is doing little more than “asking a primordial soup of robotic bits and pieces to zing through millions of generations of fluky mutations, goaded by natural selection.” Reflecting on these new creatures, Lipson shares with Ackerman a vision at once utterly mind-bending and utterly sensical:

They will have deep emotions… But they won’t necessarily be human emotions.

The kernel of this capacity, Lipson believes, lies in “the unspoken Holy Grail of a lot of roboticists” — the aspiration to create self-aware consciousness. (A goal undoubtedly quite far away, as we still struggle to understand human consciousness.) He tells Ackerman:

When a machine learns from experience, there are few guarantees about whether or not it will learn what you want… And it might learn something that you didn’t want it to learn, and yet it can’t forget. This is just the beginning.

To demystify the proposition, Ackerman points to our age-long refusal to acknowledge animal consciousness, something on which scientists now uniformly agree, much thanks to the work of Jane Goodall. Ackerman considers the criteria we presently use for conscious beings and parlays those into the question of what makes us human:

[Animals] possess a theory of mind, and can intuit what a rival might do in a given situation and act accordingly. They exhibit deceit, compassion, the ability to see themselves through another’s eyes…

I don’t think they fret and reason endlessly about mental states, as we do. They simply dream a different dream, probably much like the one we used to dream, before we crocheted into our neural circuitry the ability to have ideas about everything. Other animals may know you know something, but they don’t know you know they know. Other mammals may think, but we think about having thoughts. Linnaeus categorized us in the subspecies of Homo sapiens sapiens, adding the extra sapiens because we don’t just know, we know that we know.

This meta-knowledge is what E.F. Schumacher explored in his beautiful 1977 contemplation of the art of adequatio and how we know what we know, and it is also at the crux of what is at stake in the quest for self-aware artificial intelligence. Ackerman writes:

When people talk about robots being conscious and self-aware, they mean a range of knowing.

[…]

Lipson wants his robots to make assumptions and deductions based on past experiences, a skill underlying our much-prized autobiographical memory, and an essential component of learning. Robots will learn through experience not to burn a hand on a hot stove, and to look both ways when crossing the street.

But, like a true humanist, Ackerman wonders whether such faculties will ever penetrate the essential mystery — perhaps a “permanent mystery,” to use John Updike’s term for existence — of the human spirit:

Yet however many senses robots may come to possess—and there’s no reason why they shouldn’t have many more than we, including sharper eyesight and the ability to see in the dark — they’ll never be embodied exactly like us, with a thick imperfect sediment of memories, and maybe a handful of diaphanous dreams. Who can say what unconscious obbligato prompts a composer to choose this rhythm or that — an irregular pounding heart, tinnitus in the ears, a lover who speaks a foreign language, fond memories evoked by the crackle of ice in winter, or an all too human twist of fate? There would be no Speak, Memory from Nabokov, or The Gulag Archipelago from Solzhenitsyn, without the sentimental longings of exile. I don’t know if robots will be able to do the sort of elaborate thought experiments that led Einstein to discoveries and Dostoevsky to fiction.

Yet robots may well create art, from who knows what motive, and enjoy it based on their own brand of aesthetics, satire (if they enjoy satire), or humor. We might enjoy it, too, especially if it’s evocative of work by human artists, if it appeals to our senses. Would we judge it differently?

The iCub humanoid robot (Photograph: Sharingame CC-BY-NC-ND)

On a visit to the 2013 Living Machines Conference, Ackerman encounters iCub — a three-foot robot that has “naturally evolved theory of mind,” that developmental milestone human children reach around age three or four when they begin to understand that others have experiences, thoughts, intentions, and desires different from their own. Ackerman considers how this childlike robot attains its knowledge of self and other in relation to the world:

Through countless interactions between body and world it codifies knowledge about both. None of that is new. Nor is being able to distinguish between self and other, and intuit the other’s mental state. Engineers like Lipson have programmed that discernment into robots before. But this was the first time a robot evolved the ability all by itself. iCub is just teething on consciousness, to be sure, but it’s intriguing that the bedrock of empathy, deception, and other traits that we regard as conscious can accidentally emerge during a robot’s self-propelled Darwinian evolution. It happened like this. iCub was created with a double sense of self. If he wanted to lift a cup, his first self told his arm what to do, while predicting the outcome and adjusting his knowledge based on whatever happened. His second—we can call it “interior” — self received exactly the same feedback, but, instead of acting on the instructions, it could only try to predict what would happen in the future. If the real outcome differed from a prediction, the interior self updated its cavernous memory. That gave iCub two versions of itself, an active one and an interior “mental” one. When the researchers exposed iCub’s mental self to another robot’s actions, iCub began intuiting what the other robot might do, based on personal experience. It saw the world through another’s eyes.

There is one implication I find particularly curious — despite all that has been written about the self illusion and how it limits our true human potential, it seems nonetheless a necessary one. Without the ability to distinguish the boundaries of one’s own self against those of others, amid the amorphous jelly of the world, there would be no theory of mind and no sense of self. Consciousness, after all — at least in the empirical sense — requires self-awareness.

Robots, Ackerman argues, can also help us make sense of the world now that our own sensemaking capacity is being drowned out by an information ecosystem of exponentially swelling amounts of data. She recounts that in 1972, when she was making her writing debut with a suite of poems for the planets, Carl Sagan, who was on her doctoral committee at Cornell, gave her access to NASA photographs and reports. It was possible then, Ackerman argues, “for an amateur to learn everything humans knew about the planets.” This is no longer the case — “the Alps of raw data would take more than one lifetime to summit, passing countless PhD dissertations at campsites along the trail.” So there is incredible allure in the notion of intelligent robots that can help us trek across those Alps and make new discoveries.

How extraordinary that we’ve created peripheral brains to discover the truths about nature that we seek. We’re teaching them how to work together calmly as a society, share data at lightning speed, and cooperate so much better than we do, rubbing brains together in the invisible drawing room we sometimes call the “cloud.” Undaunted, despite our physical and mental limitations, we design robots to continue the quest we began long ago: making sense of nature. Some call it Science, but it’s so much larger than one discipline, method, or perspective.

Illustration from 'Alice in Quantumland' by Robert Gilmore. Click image for more.

This, Ackerman argues, is cause for celebration rather than lamentation. Echoing Paola Antonelli’s assertion that technology humanizes objects rather than dehumanizing people, she writes:

I find it touchingly poetic to think that as our technology grows more advanced, we may grow more human. When labor, science, manufacturing, sales, transportation, and powerful new technologies are mainly handled by savvy machines, humans really won’t be able to compete in those sectors of the economy. Instead we may dominate an economy of interpersonal or imaginative services, in which our human skills shine.

She returns to Lipson’s robots and their broader implications:

One of Lipson’s robots knows the difference between self and other, the shape of its physique, and whether it can fit into odd spaces. If it loses a limb, it revises its self-image. It senses, recollects, keeps updating its data, just as we do, so that it can predict future scenarios. That’s a simple form of self-awareness. He’s also created a machine that can picture itself in various situations — very basic thought experiments—and plan what to do next. It’s starting to think about thinking.

[…]

And with this will come emotions, because emotions, at the end of the day, have to do with the ability to project yourself into different situations — fear, various needs — and anticipate the rewards and pain in many future dramas.

And yet given how woefully flawed we humans are at making projections about our own future selves, one can’t help but wonder whether artificial intelligence, however self-correcting it may be, would succumb to the same system bugs as the very minds that created it. Even Ackerman, optimistic though she may be about the humanizing potential of robotics, remains profoundly human in her lament, rooted in our essential and rather fragile sense of the personal I:

A powerful source of existential grief comes from accepting that I won’t live long enough to find out.

But Ackerman’s wistfulness rests into a larger optimism of foresight that peers into the quintessential do-androids-dream-of-electric-sheep question as she considers the unimaginable evolution of Robot sapiens:

Will they grow attached to others, play games, feel empathy, crave mental rest, evolve an aesthetics, value fairness, seek diversion, have fickle palates and restless minds? We humans are so far beyond the Greek myth of Icarus, and its warning about overambition (father-and-son inventors and wax wings suddenly melting in the sun). We’re now strangers in a strange world of our own devising, where becoming a creator, even the Creator, of other species is the ultimate intellectual challenge. Will our future robots also design new species, bionts whose form and mental outlook we can’t yet imagine?

Way back in our own evolution, we came from fish that left the ocean and flopped from one puddle to another. In time they evolved legs, a much better way to get around on land. When Lipson’s team asked a computer to invent something that could get from point A to point B—without programming it how to walk—at first it created robots reminiscent of that fish, with multihinged legs, flopping forward awkwardly.

[…]

It’s a touching goal. Surpassing human limits is so human a quest, maybe the most ancient one of all, from an age when dreams were omens dipped in moonlight, and godlike voices raged inside one’s head. A time of potent magic in the landscape. Mountains attracted rain clouds and hid sacred herbs, malevolent spirits spat earthquakes or drought, tyrants ruled certain trees or brooks, offended waterholes could ankle off in the night, and most animals parleyed with at least one god or demon. What was human agency compared to that?

Illustration from 'The Book of Miracles,' 1552. Click image for more.

To be sure, this question of where robots are headed isn’t a negation of human agency or human potential but, rather, a celebration of it. Reflecting on our “extraordinary powers of invention, subtlety, and know-how,” on “the small unremarkable acts of mercy and heroism parents and lovers perform each day,” Ackerman concludes by reconsidering our human journey in relation to nature, the inescapable backdrop against which — to borrow Carl Sagan’s beautiful language — “everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.” She ends with an invocation at once gentle and urgent:

We can survive our rude infancy and grow into responsible, caring adults — without losing our innocence, playfulness, or sense of wonder. But first we need to see ourselves from different angles, in many mirrors, as a very young species, both blessed and cursed by our prowess. Instead of ignoring or plundering nature, we need to refine our natural place in it.

Nature is still our mother, but she’s grown older and less independent… As we’re becoming acutely aware of just how vulnerable she truly is, we’re beginning to see her limits as well as her bounty, and we’re trying to grow into the role of loving caregivers…

We are dreamsmiths and wonder-workers. What a marvel we’ve become, a species with planetwide powers and breathtaking gifts. That’s a feat to recognize and celebrate. It should fill us with pride and astonishment. The name also tells us we are acting on a long, long geological scale. I hope that awareness prompts us to think carefully about our history, our future, the fleeting time we spend on Earth, what we may leave in trust to our children (a full pantry, fresh drinking water, clean air), and how we wish to be remembered. Perhaps we also need to think about the beings we wish to become. What sort of world do we wish to live in, and how do we design that human-made sphere? …

We still have time and talent, and we have a great many choices… Our mistakes are legion, but our imagination is immeasurable.

The Human Age is a spectacular read in its entirety, pointing the poetics of science to the heart of such ensnaring open questions as what an imaginary future geologist might deduce about our civilization based on our human-made landscapes, why there might be more to the weather than we realize, and how 3-D printing will reshape the notion of the body.

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10 APRIL, 2014

The Science of Smell: How the Most Direct of Our Senses Works

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Why the 23,040 breaths we take each day are the most powerful yet perplexing route to our emotional memory.

“Get a life in which you notice the smell of salt water pushing itself on a breeze over the dunes,” Anna Quindlen advised in her indispensable Short Guide to a Happy Life. Susan Sontag listed “linen” and “the smell of newly mown grass” among her favorite things. “A man may have lived all of his life in the gray,” John Steinbeck wrote in his beautiful meditation on the meaning of life, “and then — the glory — so that a cricket song sweetens his ears, the smell of the earth rises chanting to his nose.” Why is it that smell lends itself to such poetic metaphors, sings to us so sweetly, captures us so powerfully?

That’s precisely what science historian Diane Ackerman explores in A Natural History of the Senses (public library), her 1990 prequel to the equally fantastic A Natural History of Love. Ackerman, who also happens to be a spectacular poet and the author of the gorgeous cosmic verses that Carl Sagan mailed to Timothy Leary in prison, paints the backdrop of this perplexing and unique sensory experience:

Our sense of smell can be extraordinarily precise, yet it’s almost impossible to describe how something smells to someone who hasn’t smelled it… We see only where there is light enough, taste only when we put things into our mouths, touch only when we make contact with someone or something, hear only sounds that are loud enough to hear. But we smell always and with every breath. Cover your eyes and you will stop seeing, cover your ears and you will stop hearing, but if you cover your nose and stop smelling, you will die.

Illustration by Wendy MacNaughton from 'The Essential Scratch and Sniff Guide to Becoming a Wine Expert.' Click image for more.

In fact, every breath we take in order to live is saturated with an extraordinary amount of olfactory information — a fact largely a matter of scale:

Each day, we breathe about 23,040 times and move around 438 cubic feet of air. It takes us about five seconds to breathe — two seconds to inhale and three seconds to exhale — and, in that time, molecules of odor flood through our systems. Inhaling and exhaling, we smell odors. Smells coat us, swirl around us, enter our bodies, emanate from us. We live in a constant wash of them. Still, when we try to describe a smell, words fail us like the fabrications they are…

The charm of language is that, though it is human-made, it can on rare occasions capture emotions and sensations that aren’t. But the physiological links between the smell and language centers of the brain are pitifully weak. Not so the links between the smell and the memory centers, a route that carries us nimbly across time and distance.

Indeed, that route is a greater shortcut to our cognition and psychoemotional circuitry than any of our other senses can offer. Ackerman outlines the singular qualities of our smell-sensation that set it apart from all other bodily functions:

Smell is the most direct of all our senses. When I hold a violet to my nose and inhale, odor molecules float back into the nasal cavity behind the bridge of the nose, where they are absorbed by the mucosa containing receptor cells bearing microscopic hairs called cilia. Five million of these cells fire impulses to the brain’s olfactory bulb or smell center. Such cells are unique to the nose. If you destroy a neuron in the brain, it’s finished forever; it won’t regrow. If you damage neurons in your eyes or ears, both organs will be irreparably damaged. But the neurons in the nose are replaced about every thirty days and, unlike any other neurons in the body, they stick right out and wave in the air current like anemones on a coral reef.

Illustration by Tomi Ungerer from 'The Cat-Hater's Handbook.' Click image for more.

That’s also what makes perfumes so powerful — if you’ve ever walked into a crowded room and instantly experienced a pang of emotion as you thought you smelled your ex, or your mother, or your third-grade teacher, you’ve had a first-hand testimony to the potency of smell as a trigger of emotional memory. Ackerman explains:

A smell can be overwhelmingly nostalgic because it triggers powerful images and emotions before we have time to edit them… When we give perfume to someone, we give them liquid memory. Kipling was right: “Smells are surer than sights and sounds to make your heart-strings crack.”

What’s perhaps most extraordinary is that scent lodges itself largely in the long-term memory system of the brain. And yet, we remain inept at mapping those links and associative chains when it comes to describing smells and their emotional echoes. To shed light on how perfumery plays into this paradox, Ackerman offers a taxonomy of the basic types of natural smells and how they became synthetically replicated, unleashing an intimate dance of art, science, and commerce:

All smells fall into a few basic categories, almost like primary colors: minty (peppermint), floral (roses), ethereal (pears), musky (musk), resinous (camphor), foul (rotten eggs), and acrid (vinegar). This is why perfume manufacturers have had such success in concocting floral bouquets or just the right threshold of muskiness or fruitiness. Natural substances are no longer required; perfumes can be made on the molecular level in laboratories. One of the first perfumes based on a completely synthetic smell (an aldehyde) was Chanel No. 5, which was created in 1922 and has remained a classic of sensual femininity. It has led to classic comments, too. When Marilyn Monroe was asked by a reporter what she wore to bed, she answered coyly, “Chanel No. 5.” Its top note — the one you smell first — is the aldehyde, then your nose detects the middle note of jasmine, rose, lily of the valley, orris, and ylang-ylang, and finally the base note, which carries the perfume and makes it linger: vetiver, sandalwood, cedar, vanilla, amber, civet, and musk. Base notes are almost always of animal origin, ancient emissaries of smell that transport us across woodlands and savannas.

And so we get to the actual science of smell — what actually makes us have an olfactory experience, and why we often confuse those with taste:

We need only eight molecules of a substance to trigger an impulse in a nerve ending, but forty nerve endings must be aroused before we smell something. Not everything has a smell: only substances volatile enough to spray microscopic particles into the air. Many things we encounter each day — including stone, glass, steel, and ivory — don’t evaporate when they stand at room temperature, so we don’t smell them. If you heat cabbage, it becomes more volatile (some of its particles evaporate into the air) and it suddenly smells stronger. Weightlessness makes astronauts lose taste and smell in space. In the absence of gravity, molecules cannot be volatile, so few of them get into our noses deeply enough to register as odors. This is a problem for nutritionists designing space food. Much of the taste of food depends on its smell; some chemists have gone so far as to claim that wine is simply a tasteless liquid that is deeply fragrant. Drink wine with a head cold, and you’ll taste water, they say. Before something can be tasted, it has to be dissolved in liquid (for example hard candy has to melt in saliva); and before something can be smelled, it has to be airborne. We taste only four flavors: sweet, sour, salt, and bitter. That means that everything else we call “flavor” is really “odor.” And many of the foods we think we can smell we can only taste. Sugar isn’t volatile, so we don’t smell it, even though we taste it intensely. If we have a mouthful of something delicious, which we want to savor and contemplate, we exhale; this drives the air in our mouths across our olfactory receptors, so we can smell it better.

Illustration by Wendy MacNaughton from 'The Essential Scratch and Sniff Guide to Becoming a Wine Expert.' Click image for more.

The rest of A Natural History of the Senses is just as fascinating a read, diving deeper into the mysteries and miracles of smell and our other sensory faculties. Complement it with Ackerman’s A Natural History of Love and her impossibly wonderful love letter to the Solar System, The Planets: A Cosmic Pastoral.

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