Brain Pickings

Posts Tagged ‘neuroscience’

03 JULY, 2012

Jesse Bering on the Adaptive Value and Neurochemistry of Heartbreak

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The science of why it’s possible to actually die of a broken heart.

This must be the season for fascinating books on the psychology and anthropology of sexuality, from the history of judging desire to the origins of sex. Now, in Why Is the Penis Shaped Like That?: And Other Reflections on Being Human (public library), research psychologist Jesse Bering — whom you might recall as the author of the excellent The Belief Instinct: The Psychology of Souls, Destiny, and the Meaning of Life, and who is a frequent contributor to Scientific American and Slate — examines the kaleidoscope of sexual taboos through the lens of science and psychology, from the evolution of body fluids to the politics of polyamory to the neurochemistry of heartbreak.

In one particularly fascinating chapter, highlighting studies that reveal a correlation between homophobia and repressed homosexual desire, Bering zooms in on the leaps of logic that permeate much of the rhetoric on homosexuality and the naturalistic fallacies that attempt to define notions of “normalcy”:

[I]t’s rather strange that we look for moral guidance about human sexuality from the rest of the animal kingdom, a logical fallacy in which what is ‘natural’ — such as homosexual behavior in other species — is regarded as ‘acceptable.’ It’s as if the fact that bonobos, desert toads, and emus have occasional same-sex liaisons has a moral bearing on gay rights in human beings. Even if we were the lone queer species in this godless galaxy, even if it were entirely a ‘choice’ between two consenting adults, why would that make it more reasonable to discriminate against people in homosexual relationships?

Beyond these philosophical problems with seeking out social prescriptions from a nature that is completely mute as to what we should do with our penises and vaginas, however, there’s an even bigger hurdle to taking polyamory chic beyond the tabloids, talk shows, and Internet forums and into standard bedroom practice. And that is simply the fact that we’ve evolved to empathize with other people’s suffering, including the suffering of the people we’d betray by putting our affable genitals to their evolved promiscuous use.

Heartbreak is every bit as much a psychological adaptation as is the compulsion to have sex with those other than our partners, and it throws a monster of a monkey wrench into the evolutionists’ otherwise practical polyamory.

Bering goes on to offer a kind of scientific anatomy of heartbreak, citing the familiar work of biological anthropologist Helen Fisher:

[T]here are two main stages associated with a dead and dying romantic relationship, which is so often tied to one partner’s infidelities. During the ‘protest’ stage that occurs in the immediate aftermath of rejection, ‘abandoned lovers are generally dedicated to winning their sweetheart back. They obsessively dissect the relationship, trying to establish what went wrong; and they doggedly strategize about how to rekindle the romance. Disappointed lovers often make dramatic, humiliating, or even dangerous entrances into a beloved’s home or place of work, then storm out, only to return and plead anew. They visit mutual haunts and shared friends. They phone, e-mail, and write letters, pleading, accusing, and/or trying to seduce their abandoner.’

At the neurobiological level, the protest stage is characterized by unusually heightened, even frantic activity of dopamine and norepinephrine receptors in the brain, which has the effect of pronounced alertness similar to what is found in young animals abandoned by their mothers. This impassioned protest stage — if it proves unsuccessful in reestablishing the romantic relationship — slowly disintegrates into the second stage of heartbreak, what Fisher refers to as ‘resignation/despair,’ in which the rejected party gives up all hope of ever getting back together. ‘Drugged by sorrow,’ writes Fisher, ‘most cry, lie in bed, stare into space, drink too much, or hole up and watch TV.’ At the level of the brain, overtaxed dopamine-making cells begin sputtering out, causing lethargy and depression. And in the saddest cases, this depression is linked to heart attacks or strokes, so people can, quite literally, die of a broken heart. So we may not be ‘naturally monogamous’ as a species, but neither are we naturally polygamous.

[ ... ]

[O]ne of the more fascinating things about the resignation/despair stage is the possibility that it actually serves an adaptive function that may help to salvage the doomed relationship, especially for an empathetic species such as our own…. [H]eartbreak is not easily experienced at either end, and when your actions have produced such a sad and lamentable reaction in another person, when you watch someone you care about (but no longer feel any real long-term or sexual desire to be with) suffer in such ways, it can be difficult to fully extricate yourself from a withered romance. If I had to guess — in the absence of any studies that I’m aware of to support this claim — I’d say that a considerable amount of genes have replicated in our species solely because, with our damnable social cognitive abilities, we just don’t have the heart to break other people’s hearts.

Why Is the Penis Shaped Like That?: And Other Reflections on Being Human is excellent in its entirety, woven of Bering’s rare tapestry of scientific rigor and a powerful, articulate social point of view.

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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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