Brain Pickings

Posts Tagged ‘neuroscience’

31 MAY, 2012

The Self Illusion: How Our Social Brain Constructs Who We Are

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Hume was a neuroscientist, or what early aviation has to do with the psychology of identity.

We’ve already seen that the notions of stable character and fixed personality are a myth. And yet, our culture is wired for labels and checkboxes, eager to neatly file people away into categorical cabinets and thrown into furor over the slightest inkling of multiplicity. Take, for instance, Howard Hughes, at once a legendary aviator, movie mogul, tycoon, and socialite, and a reclusive billionaire housebound by his deathly phobia of dirt. He was a fearless aviation pioneer who set and broke countless records, yet he remained terrified of dying from germs. Hughes spent his final days unbathed, dressed in rags, with long sticky hair, curling nails, and the remnants of five hypodermic needles in his arms. He was worth $2 billion.

It was this biography woven of paradoxes and dimensionality that compelled cognitive neuroscientist Bruce Hood to explore the building blocks of what we experience as the “self” in The Self Illusion: How the Social Brain Creates Identity.

Adding to the ongoing conversation on what consciousness is, how it works, and how it measures up against Truth, Hood writes:

Each morning, we wake up and experience a rich explosion of consciousness — the bright morning sunlight, the smell of roast coffee and, for some of us, the warmth of the person lying next to us in bed. As the slumber recedes into the night, we awake to become who we are. The morning haze of dreams and oblivion disperses and lifts as recognition and recall bubble up the content of our memories into our consciousness. For the briefest of moments we are not sure who we are and then suddenly ‘I,’ the one that is awake, awakens. We gather our thoughts so that the ‘I’ who is conscious becomes the ‘me’ — the person with a past. The memories of the previous day return. The plans for the immediate future reformulate. The realization that we have things to get on with remind us that it is a workday. We become a person whom we recognize.

The call of nature tells us it is time to visit the bathroom and en route we glance at the mirror. We take a moment to reflect. We look a little older, but we are still the same person who has looked in that same mirror every day since we moved in. We see our self in that mirror. This is who we are.

The daily experience of the self is so familiar, and yet the brain science shows that this sense of the self is an illusion. Psychologist Susan Blackmore makes the point that the word ‘illusion’ does not mean that it does not exist — rather, an illusion is not what it seems. We all certainly experience some form of self, but what we experience is a powerful depiction generated by our brains for our own benefit.

Hood goes on to trace how the self emerges in childhood and examines why this notion of the illusory self is among the hardest concepts to accept, contrasting the “ego theory” of the self, which holds that we are essential entities inside bodies, with Hume’s “bundle theory,” which constructs the self not as a single unified entity but as a bundle of sensations, perceptions, and thoughts lumped together. Neuroscience, Hood argues, only supports the latter. The Self Illusion tells the story of how that bundle forms and why it sticks together, revealing the brain’s own storytelling as the centripetal force of the self.

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22 MARCH, 2012

Connectome: A New Way To Think About What Makes You You

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“You are more than your genes. You are your connectome.”

The nature vs. nurture debate pitted the hard and social sciences against each other for decades, if not centuries, stirred by a central concern with consciousness, what it means to be human, what makes a person, and, perhaps most interestingly to us egocentric beings, what constitutes character and personality. In Connectome: How the Brain’s Wiring Makes Us Who We Are, MIT Professor of Computational Neuroscience Sebastian Seung proposes a new model for understanding the totality of selfhood, one based the emerging science of connectomics — a kind of neuroscience of the future that seeks to map and understand the brain much like genomics has mapped the genome.

A “connectome” denotes the sum total of connections between the neurons in a nervous system and, like “genome,” implies completeness. It’s a complex fingerprint of identity, revealing the differences between brains and, inversely, the specificity of our own uniqueness. Seung proposes a simple theory: We are different because our connectomes differ from one another. With that lens, he argues, any kind of personality change — from educating yourself to developing better habits — is a matter of rewiring your connectome.

That capacity is precisely what makes the connectome intriguing and infinitely promising — unlike the genome, which is fixed from the moment of conception, the connetome changes throughout life. Seung explains:

Neuroscientists have already identified the basic kinds of change. Neurons adjust, or “reweight,” their connections by strengthening or weakening them. Neurons reconnect by creating and eliminating synapses, and they rewire by growing and retracting branches. Finally, entirely new neurons are created and existing ones eliminated through regeneration.

We don’t know exactly how life events — your parents’ divorce, your fabulous year abroad — change your connectome. But there is good evidence that all four R’s — reweighting, reconnection, rewiring, and regeneration — are affected by your experiences. At the same time, the four R’s are also guided by genes. Minds are indeed influenced by genes, especially when the brain is ‘wiring’ itself up during infancy and childhood.*

[…]

The connectome theory of mental differences is compatible with the genetic theory, but it is far richer and more complex because it includes the effects of living in the world. The connectome theory is also less deterministic. There is reason to believe that we shape our own connectomes by the actions we take, even by the things we think. Brain wiring may make us who we are, but we play an important role in wiring up our brains.”

Harnessing the power of those four R’s, Seung believes, is the most important goal of neuroscience — but, given your connectome is 100 billion times larger than your genome and has a million times more connections than your genome has letters, it’s a daunting task. Still, new technologies and new directions of scientific curiosity are bringing us closer to understanding this microcosm of meticulously structured chaos.

Map of the C. elegans nervous system, or 'connectome,' borrowing from the language of genomics

DNA is a long chain-like molecule composed of nucleotides connoted by the letters A, C, G, and T, and your genome is the entire sequence of nucleotides in your DNA. Similarly, your connectome is the totality of connections between the neurons in your nervous system.

At the heart of Seung’s vision is a new way of thinking about human personality, a fascinating and controversial subject we’ve previously explored. He proposes an apt metaphor, underpinning which is a desire not only to find and understand our connectomes, but also to develop methods for changing and optimizing them:

In the nineteenth century, the American psychologist William James wrote eloquently of the stream of consciousness, the continuous flow of thoughts through the mind. But James failed to note that every stream has a bed. Without this groove in the earth, the water would not know in which direction of the flow. Since the connectome defines the pathways along which neural activity can flow, we might regard it as the streambed of consciousness.

The metaphor is a powerful one. Over a long period of time, in the same way that the water of the stream slowly shapes the bed, neural activity changes the connectome. The two notions of the self — as both the fast-moving, ever-changing stream, and the more stable but slowly transforming streambed** — are thus inextricably linked. This book is about the self as the streambed, the self in the connectome — the self that has been neglected for too long.”

In elaborating on this dichotomy of the self, Seung echoes Daniel Kahneman’s notion of the experiencing self vs. the remembering self:

One self changes rapidly from moment to moment, becoming angry and then cheering up, thinking about the meaning of life and then the household chores, watching the leaves fall outside and then the football game on television. This self is the one intertwined with consciousness. Its protean nature derives from the rapidly changing patterns of neural activity in the brain.

The other self is much more stable. It retains memories from childhood over an entire lifetime. Its nature — what we think of as personality — is largely constant, a fact that comforts family and friends. The properties of this self are expressed while you are conscious, but they continue to exist during unconscious states like sleep. This self, like the connectome, changes only slowly over time. This is the self invoked by the idea that you are your connectome.”

Sample Seung’s insights with his 2010 TEDGlobal talk:

Scientific American has an excellent Q&A with Seung about Connectome.

* For more on this fascinating early wiring, especially as it applies to our emotional lives, see the excellent A General Theory of Love.

** For a different metaphor articulating an analogous concept, see Jonathan Haidt’s The Happiness Hypothesis, where he describes the self as the interplay between the conscious “rider” and the unconscious “elephant” he struggles to command.

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15 FEBRUARY, 2012

Guitar Zero: A Neuroscientist Debunks the Myth of “Music Instinct” and Learns to Play

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On nature, nurture, and the neural pathways of possibility.

Are musicians born or made? What is the line between skill and talent in any domain, and can we acquire either later in life? That’s exactly what neuroscientist Gary Marcus explores in Guitar Zero: The New Musician and the Science of Learning — a fascinating journey into the limits of human reinvention.

In an effort to reconcile his lifelong passion for music with his self-admitted chronic musical inaptitude, Marcus set out to debunk one of science’s longest-running theories about learning — that there are “critical periods” in which complex skills can be learned, and that they slam shut after adolescence.

If critical periods aren’t quite so firm as people once believed, a world of possibility emerges for the many adults who harbor secret dreams — whether to learn a language, to become a pastry chef, or to pilot a small plane. And quests like these, no matter how quixotic they may seem, and whether they succeed in the end or not, could bring unanticipated benefits, not just for their ultimate goals but of the journey itself. Exercising our brains helps maintain them, by preserving plasticity (the capacity of the nervous system to learn new thing), warding off degeneration, and literally keeping the blood flowing. Beyond the potential benefits for our brains, there are benefits for our emotional well-being, too. There may be no better way to achieve lasting happiness — as opposed to mere fleeting pleasure — than pursuing a goal that helps us broaden our horizons.

To his astonishment, however, Marcus found a dearth of scientific literature and research on music learning in people of his age. The problem, it turned out, wasn’t lack of scientific interest but, rather, a lack of subjects — studying the outcomes of adults who put in 10,000 hours of practice proved difficult since most people of that age have life responsibilities that prevent them from putting in that time in the first place. So, Marcus decided to turn himself into the guinea pig.

For a glimmer of hope, he looked to a number of well-known musicians who arrived at their particular musical talent late in life — Patti Smith didn’t consider becoming a professional singer until she was in her mid-twenties, iconic jazz guitarist Pat Martino relearned to play after a brain aneurysm at the age of 35, and New Orleans keyboard legend Dr. John switched from guitar to piano when he was 21 after an injury, then won the first of his five Grammys at the age of 48. Having no such aspirations of grandeur, Marcus, aged 38 and with a documented lack of rhythm, still found himself desperately longing to learn to play the guitar. As he puts it, “Perhaps few people had less talent for music than I did, but few people wanted more badly to be able to play.” So he confronted the fundamental question:

Could persistence and a lifelong love of music overcome age and a lack of talent? And, for that matter, how did anyone of any age become musical?”

Curiously, one of the most influential experiments on critical periods comes from barn owls who, like bats, rely heavily on sound to navigate; but, unlike bats, they see better than bats do, and one of the first things they do after hatching is calibrating their ears with their eyes, attuning what they hear to what they see. But because this navigational mapping of auditory information depends on the exact distance between their eyes and ears, which changes as the owl grows, it can’t be hardwired at birth.

To study how the owls calibrate their visual and auditory worlds, Stanford biologist Eric Knudsen devised a clever experiment, in which he raised owls in a kind of virtual reality world where prisms shifted everything by 23 degrees, forcing the owl to adjust its internal map of the world. Knudsen found that young owls learned to compensate for the distortion easily, and older owls could not — at least not in one go. But as soon as the 23 degrees were broken down in chunks — a few weeks at 6 degrees, another few at 11, and so forth — the adult owls were able to make the adjustment.

Using this insight, Marcus turned to David Mead’s Crash Course: Acoustic Guitar, which broke guitar playing into the kind of bite-sized morsels fit for the human equivalent of adult owls. It gave Marcus the basics, and thus the first step in rewiring his own brain.

This book is about how I began to distinguish my musical derriere from my musical elbow, but it’s not just about me: it’s also about the psychology and brain science of how anybody, of any age — toddler, teenager, or adult — can learn something as complicated as a musical instrument.”

Wilder Penfield's cortical homunculus, a pictorial representation of the neural tissue in the primary motor cortex assigned to different body parts, illustrates that the exact amount of 'cortical real estate' varies between body parts, with the more sensitive ones getting more real estate. Marcus suggests a try-this-at-home test:

'You can confirm this with the aid of a pin and a trusted friend. Close your eyes as the friend gently pokes you with the pin. In areas with heavy cortical representation, you will be able to easily discriminate closely spaced pinpricks; in areas with light cortical representation, you will sometimes be unable to distinguish two pinpricks that are close together but not identical.'

Along the way, Marcus explores the basic elements of music and how it evolved culturally and biologically. He dives deep into the popular “ten thousand hours” theory of mastery, developed by cognitive psychologist Anders Ericsson, “the world’s leading expert on expertise,” and examines Ericsson’s second, lesser-known prerequisite for expertise — the notion of “deliberate practice,” which describes the constant sense of self-evaluation and a consistent focus on one’s weaknesses rather than playing on one’s strengths. In fact, the practice of targeting specific weaknesses is known as the “zone of proximal development” and offers a framework for everything from education to videogames:

[The "zone of proximal development" is] the idea that learning works best when the student tackles something that is just beyond his or her current reach, neither too hard nor too easy. In classroom situations, for example, one team of researchers estimated that its’ best to arrange things so that children succeed roughly 80 percent of the time; more than that, and kids tend to get bored; less, and they tend to get frustrated. The same is surely true of adults, too, which is why video game manufacturers have been known to invest millions in play testing to make sure that the level of challenge always lies in that sweet spot of neither too easy nor too hard.”

But what makes Guitar Zero exceptional isn’t simply that it simultaneously calls into question the myth of the music instinct and confronts the idea that talent is merely a myth — at its heart is a much bigger question about the boundaries of our capacity for transformation and, ultimately, the mechanics of fulfillment and purpose.

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