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Category: Mind & Brain
Is the Purpose of Sleep to Let Our Brains “Defragment,” Like a Hard Drive?
Neuroskeptic is a neuroscientist who takes a skeptical look at his own field and beyond at the Neuroskeptic blog.
Why do we sleep? We spend a third of our lives doing so, and all known animals with a nervous system either sleep, or show some kind of related behaviour. But scientists still don’t know what the point of it is.
There are plenty of theories. Some researchers argue that sleep has no specific function, but rather serves as evolution’s way of keeping us inactive, to save energy and keep us safely tucked away at those times of day when there’s not much point being awake. On this view, sleep is like hibernation in bears, or even autumn leaf fall in trees.
But others argue that sleep has a restorative function—something about animal biology means that we need sleep to survive. This seems like common sense. Going without sleep feels bad, after all, and prolonged sleep deprivation is used as a form of torture. We also know that in severe cases it can lead to mental disturbances, hallucinations and, in some laboratory animals, eventually death.
Waking up after a good night’s sleep, you feel restored, and many studies have shown the benefits of sleep for learning, memory, and cognition. Yet if sleep is beneficial, what is the mechanism?
Recently, some neuroscientists have proposed that the function of sleep is to reorganize connections and “prune” synapses—the connections between brain cells. Last year, one group of researchers, led by Gordon Wang of Stanford University reviewed the evidence for this idea in a paper called Synaptic plasticity in sleep: learning, homeostasis and disease.
This illustration, taken from their paper, shows the basic idea:
While we’re awake, your brain is forming memories. Memory formation involves a process called long-term potentiation (LTP), which is essentially the strengthening of synaptic connections between nerve cells. We also know that learning can actually cause neurons to sprout entirely new synapses.
Yet this poses a problem for the brain. If LTP and synapse formation is constantly strengthening our synapses, and we are learning all our lives, might the synapses eventually reach a limit? Couldn’t they “max out,” so that they could never get any stronger?
Worse, most of the synapses that strengthen during memory are based on glutamate. Glutamate is dangerous. It’s the most common neurotransmitter in the brain, and it’s also a popular flavouring: “MSG”, monosodium glutamate. But in the brain, too much of it is toxic.
Youth, Regret, and the Pain of Possibilities Lost
Science journalist Robin Marantz Henig is a contributing writer at The New York Times Magazine. Her next book, co-authored with her daughter Samantha Henig, is called Twentysomething: Why Do Young Adults Seem Stuck? and will be out in November.
Is regret something you accumulate in your life, piling it up as you remember an ever-increasing number of things that really could have gone better? If so, you’d think that young people would have fewer regrets than older ones, since they haven’t lived as long and haven’t missed as many chances—and if they have missed a chance at some adventure or relationship, they’re more likely to think that the chance will come around again.
But a recent study by Stefanie Brassen and her colleagues at University Medical Center Hamburg-Eppendorf in Germany suggests that young people feel more regret than old people, largely because the older people seem to be quashing those nasty feelings before the feelings overtake them. Indeed, they found that the only 60-somethings who experienced regret at the same level as 20-somethings were those who were depressed.
I think it’s worth considering, though, whether the German investigators really were tapping into regret at all, or a different aspect of youth psychology.
Brassen and her colleagues simulated regret by having her subjects play a Let’s Make a Deal-type computer game in which they opened a succession of boxes to earn cash. They could keep opening boxes and keep accumulating cash as long as they stopped before they opened the box containing a pop-out devil. If they got to the devil, the game was over and they had to give back everything they’d earned in that round.
The researchers were less interested in how many boxes the subjects opened than in how they felt about the chances they missed. After the round was over, the investigators revealed the contents of the unopened boxes. The more boxes the subjects could have opened before getting to the devil, the more regret they were expected to feel, since they could have earned even more money if they’d been just a little more daring.
Does Brain Scanning Show Just the Tip of the Iceberg?
By Neuroskeptic, a neuroscientist who takes a skeptical look at his own field, and beyond. A different version of this post appeared on the Neuroskeptic blog.
Brain-scanning studies may be giving us a misleading picture of the brain, according to recently published findings from two teams of neuroscientists.
Both studies made use of a much larger set of data than is usual in neuroimaging studies. A typical scanning experiment might include around 20 people, each of whom performs a given task maybe a few dozen times. So when French neuroscientists Benjamin Thyreau and colleagues analysed the data from 1,326 people, they were able to increase the statistical power of their experiment by an order of magnitude. An American team led by Javier Gonzalez-Castillo, on the other hand, only had 3 people, but each one was scanned while performing the same task 500 times over.
In both cases, the researchers found that close to the whole of the brain “lit up”—that is, showed increased metabolic activity—when people were doing simple mental tasks, compared to just resting. In one case, it was seeing videos of people’s faces; in the other, it was deciding whether stimuli on the screen were letters or numbers. Both studies made use of functional magnetic resonance imaging (fMRI), which uses powerful magnetic fields to image the brain and detect the changes in blood oxygen caused by differences in the firing rate of the cells in different areas.
There have been many thousands of fMRI papers published since the technique was developed 20 years ago. The great majority of these have produced the familiar “blob” plots showing that different kinds of mental processes engage localized activity in particular parts of the brain. Thyreau and Gonzalez-Castillo, however, were able to detect effects too small to be noticed in such neuroimaging experiments, and found that rather than isolated blobs, large swathes of the brain were involved. This doesn’t mean that everywhere responded equally to the task: the signal was stronger in some areas of the brain than in others, but there were no clear-cut divisions between “active” and “inactive” areas.
While the new results don’t overturn the localization theory as such, they do show that it’s only part of the picture. The blobs are real enough, as they show us the areas where activation is strongest, but it’s misleading to think of these areas as the only places involved in a particular task. Other activations, smaller or less consistent but no less real, are hidden under the threshold of statistical noise. fMRI experiments may just be showing us the tip of the iceberg of brain activity.
5 Ways to Turn a Liberal Into a Conservative (At Least Until the Hangover Sets In)
By Chris Mooney, a science and political journalist, blogger, podcaster, and experienced trainer of scientists in the art of communication. He is the author of four books, including the just-released The Republican Brain: The Science of Why They Deny Science and Reality and the New York Times-bestselling The Republican War on Science. He blogs for Science Progress, a website of the Center for American Progress and Center for American Progress Action Fund, and is a host of the Point of Inquiry podcast.
Voting image via Shutterstock
One of the first questions that usually comes up when people ask me about my book The Republican Brain is: “How do you explain my Uncle Elmer, who grew up a hard core Democrat and was very active in the union, but now has a bumper sticker that reads ‘Don’t Tread on Me’?”
Okay: I’m making this question up, but it’s pretty close to reality. People constantly want to know how to explain political conversions—cases in which individuals have changed political outlooks, sometimes very dramatically, from left to right or right to left.
When I get the standard political conversion question, the one I ask in return may come as a surprise: “Are you talking about permanent political conversions, or temporary ones?”
You see, Uncle Elmer is less interesting to me—and in some ways, less interesting to the emerging science of political ideology—than the committed Democrat who became strongly supportive of George W. Bush right after 9/11, but switched back to hating him a few months later. What caused that to happen? Because it certainly doesn’t seem to have much to do with thinking carefully about the issues.
Indeed, the growing science of politics has uncovered a variety of interventions that can shift liberal people temporarily to the political right. And notably, none of them seem to have anything substantive to do with policy, or with the widely understood political differences between Democrats and Republicans.
Here is a list of five things that can make a liberal change his or her stripes:
Distraction. Several studies have shown that “cognitive load”—in other words, requiring people to do something that consumes most or all of their attention, like listening to a piece of music and noting how many tones come before each change in pitch—produces a conservative political shift.
Cheap Soul Teleportation, Coming Soon to a Theater Near You?
Mark Changizi is an evolutionary neurobiologist and director of human cognition at 2AI Labs. He is the author of The Brain from 25000 Feet, The Vision Revolution, and his newest book, Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man.”
Also check out his related commentary on a promotional video for Project Glass, Google’s augmented-reality project.
Experience happens here—from my point of view. It could happen over there, or from a viewpoint of an objective nowhere. But instead it happens from the confines of my own body. In fact, it happens from my eyes (or from a viewpoint right between the eyes). That’s where I am. That’s consciousness central—my “soul.” In fact, a recent study by Christina Starmans at Yale showed that children and adults presume that this “soul” lies in the eyes (even when the eyes are positioned, in cartoon characters, in unusual spots like the chest).
The question I wish to raise here is whether we can teleport our soul, and, specifically, how best we might do it. I’ll suggest that we may be able to get near-complete soul teleportation into the movie (or video game) experience, and we can do so with some fairly simple upgrades to the 3D glasses we already wear in movies.
Consider for starters a simple sort of teleportation, the “rubber arm illusion.” If you place your arm under a table out of your view, and have a fake, rubber, arm on the table where your arm usually would be, an experimenter who strokes the rubber arm while simultaneously stroking your real arm on the same spot will trick your brain into believing that the rubber arm is your arm. Your arm—or your arm’s “soul”—has “teleported” from under the table and within your real body into a rubber arm sitting well outside of your body.
It’s the same basic trick to get the rest of the body to transport. If you were to wear a virtual reality suit able to touch you in a variety of spots with actuators, then you can be presented with a virtual experience – a movie-like experience – wherein you can see your virtual body being touched and the bodysuit you’re wearing simultaneously touches your real body in those same spots. Pretty soon your entire body has teleported itself into the virtual body.
And… Yawn, we all know this. We saw James Cameron’s Avatar, after all, which uses this as the premise.
My question here is not whether such self-teleportation is possible, but whether it may be possible to actually do this in theaters and video games. Soon.
Santorum’s Slipping Tongue: What Do Speech Errors Really Reveal About Inner Thoughts?
Julie Sedivy is the lead author of Sold on Language: How Advertisers Talk to You And What This Says About You. She contributes regularly to Psychology Today and Language Log. She is an adjunct professor at the University of Calgary, and can be found at juliesedivy.com and on Twitter/soldonlanguage.
Last week, a verbal stumble by Republican candidate Rick Santorum led to a fresh batch of accusations that he harbors racist sentiments. Here is a video clip and transcript, from a speech delivered on March 27th 2012 in Janesville, Wisconsin:
We know, we know the candidate Barack Obama, what he was like. The anti-war government nig- uh, the uh America was a source for division around the world.”
Almost immediately, this video clip began to zip around the internet, with many people arguing that Santorum had caught himself in the middle of uttering a racial slur against Barack Obama, inadvertently revealing his true attitude. The presumption behind these arguments is that “Freudian slips” reflect a layer of thoughts and attitudes that sometimes slip past the mental guards of consciousness and bubble to the surface. That they’re the window to what someone was really thinking, despite his best efforts to conceal it.
But decades of research in psycholinguistics reveal that speech errors are rarely this incriminating. The vast majority of them come about simply because of the sheer mechanical complexity of the act of speaking. They’re less like Rorschach blot tests and more like mundane assembly-line mistakes that didn’t get caught by the mind’s inner quality control.
Speech errors occur because when it comes to talking, the mind cares much more about speed than it does about accuracy. We literally speak before we’re done thinking about what we’re going to say, and this is true not just for the more impetuous amongst us, but for all speakers, all of the time. Speech production really is like an assembly line, but an astoundingly frenzied one in which an incomplete set of blueprints is snatched out of the hands of the designers by workers eager to begin assembling the product before it’s fully sketched out.
Votes and Vowels: A Changing Accent Shows How Language Parallels Politics
Julie Sedivy is the lead author of Sold on Language: How Advertisers Talk to You And What This Says About You. She contributes regularly to Psychology Today and Language Log. She is an adjunct professor at the University of Calgary, and can be found at juliesedivy.com and on Twitter/soldonlanguage.
There’s been a good bit of discussion and hand-wringing lately over whether the American public is becoming more and more politically polarized and what this all means for the future of our democracy. You may have wrung your own hands over the issue. But even if you have, chances are you’re not losing sleep over the fact that Americans are very clearly becoming more polarized linguistically.
It may seem surprising, but in this age where geographic mobility and instant communication have increased our exposure to people outside of our neighborhoods or towns, American regional dialects are pulling further apart from each other, rather than moving closer together. And renowned linguist William Labov thinks there’s a connection between political and linguistic segregation.
Dialect regions as defined by the Atlas of North American English
In the final volume of his seminal book series Principles of Linguistic Change, Labov spends a great deal of time discussing a riveting linguistic change that’s occurring in the northern region of the U.S. clustering around the Great Lakes. This dialect region is called the Inland North, and runs from just west of Albany to Milwaukee, loops down to St. Louis, and traces a line to the south of Chicago, Toledo, and Cleveland.
Thirty-four million speakers in this region are in the midst of a modern-day re-arrangement of their vowel system. Labov thinks it all started in the early 1800′s when the linguistic ancestors of this new dialect began to pronounce “a” in a distinct way: the pronunciation of “man” began to lean towards “mee-an”, at least some of the time. But it wasn’t until the 1960s that this sound change began to trigger a real domino effect.
Are We “Meant” to Have Language and Music?
Mark Changizi is an evolutionary neurobiologist and director of human cognition at 2AI Labs. He is the author of The Brain from 25000 Feet, The Vision Revolution, and his newest book, Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man.”
What do ironing and hang-gliding have in common? Not much really, except that we weren’t designed to do either of them. And that goes for a million other modern-civilization things we regularly do but are not “supposed” to do. We’re fish out of water, living in radically unnatural environments and behaving ridiculously for a great ape. So, if one were interested in figuring out which things are fundamentally part of what it is to be human, then those million crazy things we do these days would not be on the list.
iStockphoto
But what would be on the list?
At the top of the list of things we do that we’re supposed to be doing, and that are at the core of what it is to be human rather than some other sort of animal, are language and music. Language is the pinnacle of usefulness, and was key to our domination of the Earth (and the Moon). And music is arguably the pinnacle of the arts. Language and music are fantastically complex, and we’re brilliantly capable at absorbing them, and from a young age. That’s how we know we’re meant to be doing them, i.e., how we know we evolved brains for engaging in language and music.
But what if this gets language and music all wrong? What if we’re not, in fact, meant to have language and music? What if our endless yapping and music-filled hours each day are deeply unnatural behaviors for our species? (What if the parents in Footloose* were right?!)
I believe that language and music are, indeed, not part of our core—that we never evolved by natural selection to engage in them. The reason we have such a head for language and music is not that we evolved for them, but, rather, that language and music evolved—culturally evolved over millennia—for us. Our brains aren’t shaped for these pinnacles of humankind. Rather, these pinnacles of humankind are shaped to be good for our brains.
What’s Causing Cheerleader Hysteria? Signs of a Struggle Within the Brain
Vaughan Bell is a clinical and research psychologist based at the Institute of Psychiatry, King’s College London. He’s also working on a book about hallucinations due to be out in 2013.
Cheerleaders from a small town in New York state have been making headlines because several of them began to display tics and involuntary movements that have been diagnosed as conversion disorder—a situation which has often described in the media as being due to “mass hysteria” or a “mystery illness.” I can’t say for sure whether the diagnosis of conversion disorder is accurate or not because I’ve not been clinically involved with the affected people, and if I had, I couldn’t talk about it due to patient confidentiality, but what I can say is that some of the media reporting of conversion disorder, “hysteria” and its related concepts has been highly confused.
Hysteria is used in everyday language to mean “panic” but it has a long history as a medical condition, originating from Hippocrates who thought that a whole range of symptoms could be caused by the womb “wandering” around the body. As you might expect, it was traditionally thought of as a female disease until the French neurologist Jean-Martin Charcot shocked the medical world by reporting the first male cases. Although the connection with a wandering womb was comprehensively disproved, doctors were still puzzled by patients who seemed to have neurological disorders without damage to the brain and nervous system. The core definition of hysteria as neurological symptoms without neurological damage remains with us today.
A student of Charcot’s, Sigmund Freud, became curious about the condition and added another element to the definition, which both made his career and became the basis of psychoanalysis itself. As a neurologist, Freud came to believe that mental energy was equivalent to neural energy and, therefore, our mind obeys something akin to the laws of thermodynamics. The first such law says that energy cannot be created or destroyed, only converted into another form. This is why Freudian psychology is full of mechanical concepts such as “repression” and “conversion” and the idea that all emotional disturbance must be “processed” or “dealt with” (think: a release valve) or else it will express itself in another form (think: a burst or bulging pipe). Many of the theory’s predictions have been disproved but the theory lives on and, to a great extent, it has become what we unfortunately think of as common sense. Nevertheless, Freud applied the same thinking to hysteria, saying that these seemingly neurological symptoms can appear without neurological damage because the unconscious mind is shutting down the body to prevent us from encountering a deep emotional disturbance. A bit like locking the basement in a rushed attempt to deal with a burst pipe—the problem is easier to ignore but not any less serious.
Is Your Language Making You Broke and Fat? How Language Can Shape Thinking and Behavior (and How It Can’t)
Julie Sedivy is the lead author of Sold on Language: How Advertisers Talk to You And What This Says About You. She contributes regularly to Psychology Today and Language Log. She is an adjunct professor at the University of Calgary, and can be found at juliesedivy.com and on Twitter/soldonlanguage.
Keith Chen, an economist from Yale, makes a startling claim in an unpublished working paper: people’s fiscal responsibility and healthy lifestyle choices depend in part on the grammar of their language.
Here’s the idea: Languages differ in the devices they offer to speakers who want to talk about the future. For some, like Spanish and Greek, you have to tack on a verb ending that explicitly marks future time—so, in Spanish, you would say escribo for the present tense (I write or I’m writing) and escribiré for the future tense (I will write). But other languages like Mandarin don’t require their verbs to be escorted by grammatical markers that convey future time—time is usually obvious from something else in the context. In Mandarin, you would say the equivalent of I write tomorrow, using the same verb form for both present and future.
Chen’s finding is that if you divide up a large number of the world’s languages into those that require a grammatical marker for future time and those that don’t, you see an interesting correlation: speakers of languages that force grammatical marking of the future have amassed a smaller retirement nest egg, smoke more, exercise less, and are more likely to be obese. Why would this be? The claim is that a sharp grammatical division between the present and future encourages people to conceive of the future as somehow dramatically different from the present, making it easier to put off behaviors that benefit your future self rather than your present self.
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