Sleep deprivation. Stress positions. Waterboarding. These interrogation techniques used by the Bush administration in the war on terror were explained, at the time, as harsh but necessary tactics that forced captives to give up names, plots, and other information. But a new look at the neurobiological effects of prolonged stress on the brain suggests that torture damages the memory, and therefore often produces bad intelligence.
Irish neuroscientist Shane O’Mara reviewed the scientific literature about the effect of stress on memory and brain function after reading descriptions of the CIA’s Bush-era interrogation methods. The methods were detailed in previously classified legal memos released in April. O’Mara did not examine or interview any of those interrogated by the CIA [AP].
His findings: “These techniques cause severe, repeated and prolonged stress, which compromises brain tissue supporting memory and executive function” [Wired.com]. The study, to be published in the journal Trends in Cognitive Sciences, took note of the effect of the stress hormone cortisol on the brain, as well as the fear-related hormone noradrenaline’s impact on memory and the ability to distinguish true from false.
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Some coma patients who appear to be completely unresponsive to the outside world are still capable of the most basic kind of learning, according to a small new study. Researchers found that both vegetative and “minimally conscious” patients were capable of a Pavlovian response, learning to associate a noise with a slightly unpleasant stimulus.
The researchers built on the work of 19th-century Russian psychologist Ivan Pavlov, who famously conditioned his dogs to salivate at the ring of a bell by associating the sound with the presentation of food. In this case, they sounded a tone, which was followed about 500 milliseconds later with a light puff of air to the eye [Scientific American]. At first the patients only responded after the puff of air by blinking or twitching or flinching. But after repeated trials, 15 of the 22 patients began to blink or flinch immediately after the tone sounded, before the puff of air. Electrodes by their eyes picked up the subtle muscle movements.
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A person can witness an event in real life, see a doctored video of the same event, and then convince themselves that what they saw on the video is what actually happened, according to a recent study that casts doubt on the reliability of eyewitness testimony.
Psychologists set up an experiment where they filmed two people sitting side by side–one experimental subject and one researcher pretending to be a participant–playing a gambling game where they bet phony money on whether or not they could answer multiple choice questions correctly. They were told that the person with the most money at the end would win a prize.
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You may remember more than your conscious brain knows, according to a nifty new study that will soon be published in the journal Neuron. Researchers gave college students memory tests while closely monitoring both their eye movements and their brain activity, and found that certain patterns revealed that a student was retrieving the memory of the right answer–although his conscious brain often never got it.
In the experiment, researchers presented a long sequence of pictures of faces paired with an outdoor scene, and finally showed the subject one landscape photo along with three faces, asking him to pick out the face that had originally be paired with the landscape. Immediately, activity in the brain region called the hippocampus increased, followed 500 to 750 milliseconds later by eye movements directed toward one of the three faces. When the hippocampus was more active, the eyes lingered on the correct face. Less hippocampus activity occurred when the eyes dwelled on an incorrect face…. The results suggest that eye movements can reveal unconscious memories activated in the hippocampus [Science News]. This pattern stayed the same regardless of whether the subject ultimately settled on the right answer.
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During both work hours and leisure time, a growing number of people have become extravagant multitaskers, flitting between Web browsing, texting, emailing, and maybe even throwing in some old-fashioned television or print media for good measure. But a surprising new study has found that those who multitask the most are far worse at it than those people who focus on fewer tasks simultaneously. Says study coauthor Clifford Nass: “The huge finding is, the more media people use the worse they are at using any media. We were totally shocked” [AP].
The researchers compared high- and low-multitaskers on a variety of psychological tests, according to the study published in the Proceedings of the National Academy of Sciences. They found that the high-multitaskers were worse at ignoring irrelevant information, worse at organizing information, and took more time to switch between tasks. That final finding particularly surprised the researchers, considering the need to switch from one thing to another in multitasking. “They couldn’t help thinking about the task they weren’t doing,” lead author Eyal Ophir said [AP].
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In the hopes of combating rising suicide and mental illness rates, the U.S. Army is implementing a mental stress training course for all 1.1 million members of the National Guard, reservists, and active-duty soldiers.
The training, the first of its kind in the military, is meant to improve performance in combat and head off the mental health problems, including depression, post-traumatic stress disorder and suicide, that plague about one-fifth of troops returning from Afghanistan and Iraq [The New York Times]. The program will be taught by Army sergeants in classes that generally last about an hour-and-a-half, and will begin in October at two bases before spreading to all service members. The training will also be available for family members and civilian employees.
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Chronically stressed rats make decisions based on habit, new research has shown, even when those habits no longer produce the maximum benefit. Researchers say the stressed out rats’ inability to adapt to changing circumstances seems similar to the human response to chronic stress. How often do we talk about burned-out people who are just going through the motions? [ABC News]
In the study, published in Science, the researchers subjected the rats to several tests. In one experiment, the rats were trained to press a lever to receive a reward (either food pellets or sucrose). After two weeks of training, they were given full access to the reward and allowed to consume as much as they desired. When presented with the lever again, control animals stopped pressing the lever, but stressed animals didn’t. If you get the dessert for free, [study coauthor Rui] Costa said, there’s no need to work for it. “That’s what control animals do,” but stressed animals work anyway [The Scientist].
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A new study based on neurological data and brain specimens from a group of nuns, known as the Nun Study, confirms that language skills earlier in life are linked to Alzheimer’s disease risk in older age. But it also adds new, puzzling information to our knowledge about the disease: The brains of the women who did not have Alzheimer’s symptoms had larger brain cells, or neurons, but not necessarily fewer of the plaques and tangles characteristic of the disease.
To assess language skills early in life, researchers examined essays written by 14 women when they entered the convent, looking for the number of ideas expressed in every group of 10 words. A previous study linked grammatically complex writing skills to a decreased risk of dementia, and this study confirmed it: The essays written by women who maintained their memory scored 20 percent higher on language tests. “This is the second independent sample with the same result. We’re back to the metaphor of the brain as a computer and a muscle,” said [geriatric psychiatrist] Dr. Gary J. Kennedy…. “In volunteers who had no signs of Alzheimer’s but did have the plaques and tangles, the neurons were actually larger and more functional with more connections” [U.S. News and World Report].
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If you get on a mockingbird’s enemy list, expect to be dive-bombed every time you come within the bird‘s sight. That’s one lesson that can be taken from a new study which proved that mockingbirds can recognize individual people, and attack those who have bothered their nests in the past. While ornithologists knew that certain highly intelligent birds like parrots and crows can recognize humans in a lab setting, they were surprised to find similar behavior in a songbird living in the wild. This paper is “a beauty,” says John Fitzpatrick, an ornithologist at Cornell University. “It’s amazing what a bird brain can do” [ScienceNOW Daily News].
The study was prompted by a series of bird attacks. A graduate student involved in research on bird nesting noticed that when she would make repeat visits to peoples’ yards the birds would alarm and attack her, while they would ignore people gardening or doing other things nearby…. Indeed, it seemed they could even recognize her car, and she had to start parking around the corner [AP]. So the researchers designed an experiment to investigate whether the birds really could identify an individual person.
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Young adults with a genetic variant that increases their chance of developing Alzheimer’s later in life also have increased activity in the section of their brain devoted to memory, a new study has found. Researchers say the results suggest that the memory portion of the brain, the hippocampus, may eventually get worn out from a lifetime of overuse.
Researchers conducted fMRI brain scans of 36 volunteers, half of whom had at least one copy of the gene, known as APOE4. “We were surprised to see that even when the volunteers carrying APOE4 weren’t being asked to do anything, you could see the memory part of the brain working harder than it was in the other volunteers,” [study coauthor Christian] Beckmann said…. “Not all APOE4 carriers go on to develop Alzheimer’s, but it would make sense if in some people, the memory part of the brain effectively becomes exhausted from overwork and this contributes to the disease” [Reuters].
However, the researchers note that they’re far from proving this hypothesis, and say that it’s impossible to tell whether the extra activity contributes to Alzheimer’s symptoms later on or is just a sign of inefficient brain circuitry in the hippocampus [New Scientist].
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Sleep may be a way to sweep out the brain and get it ready for a new day of building connections between neurons, according to two new studies of fruit flies. The studies support the controversial theory that sleep weakens or entirely dissolves some synapses, the connections between brain cells. “We assume that if this is happening, it is a major function, if not the most important function, of sleep” [Science News], says Chiara Cirelli, a coauthor of the first study, published in Science.
Pruning synapses may be a practical necessity to keep the brain from being overwhelmed, says Paul Shaw, coauthor of the second study (also published in Science). “There are a number of reasons why the brain can’t indefinitely add synapses – including the finite spatial constraints of the skull. We were able to track the creation of new synapses in fruit flies during learning experiences – and to show that sleep pushed that number back down” [Telegraph], he says.
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To figure out whether you’ll like the restaurant around the corner or that new guy in accounting or a vacation in Madrid, or just about anything else you’ve never personally experienced, try asking a stranger who has [Time]. That stranger is likely to predict, better than you can yourself, how much enjoyment you’ll get from that new experience (or the guy in accounting).
Previous research has shown that people tend to overestimate how disappointed or unhappy they will be after a perceived negative event, such as being denied a promotion, as well as how happy they will feel after positive events, like winning a prize. Building on that knowledge, psychology professor Daniel Gilbert conducted experiments in which he asked people to predict how much they’d enjoy a future event that they knew nothing about—except how much a total stranger had enjoyed it. Those people, it turns out, made extremely accurate predictions [WebMD].
In one experiment, women were asked to partake in “speed dating.” Subjects given reviews by women who had already “dated” participating men were able to gauge how well a date would go better than those who were only shown a picture and profile, and asked to come to their own conclusions.
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Using not much more than a brain scanner, scientists have successfully found a way to read people’s minds—or at least, certain thoughts in them. A London research team was able to determine where its volunteer subjects were located, in a computer-generated virtual environment, by using fMRI scanning to analyze activation patterns in the hippocampus area of their brains. After correlating this information with the subjects’ movements, the researchers found that they could accurately predict their subjects’ locations based solely on the scanner read-out.
The findings may bring scientists one step closer to understanding the workings of the hippocampus, the part of the brain responsible for short-term memory and spatial relationships but which has been too disorganized for scientists, until now, to decode. Led by Eleanor Maguire, the researchers focused on groups of neurons identified by Maguire in an earlier study of London taxi drivers, whose hippocampi were hyperdeveloped by years of mental navigation through the city’s mazelike streets…. The results “are an intriguing first step toward using fMRI to read out information about visuo-spatial scenes,” [Wired] said Arne Ekstrom, a California-based neuroscientist.
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Men who are older when they father children tend to have children who score slightly lower on IQ tests and other measures of cognitive function, according to a new study. That conclusion, which researchers called unexpected and startling, adds to a recent surge of evidence that, like women, men also have a biological clock. Older fathers have been linked to a range of health problems, including an increased risk of birth deformities, autism and neuropsychiatric conditions, such as schizophrenia and bipolar disorder…. Experts believe mutations in a man’s sperm, which build over time, may be a factor [BBC News].
However, lead researcher John McGrath says that the findings shouldn’t cause panic. “With respect to childhood intelligence, a vast array of factors is far more powerful than paternal age,” McGrath cautions. These factors include nutrition, health care and family income [Science News]. Researchers say that adjusting for socioeconomic factors like family income lessened the link between paternal age and children’s cognitive scores, but didn’t erase it. The average IQ of a child born to a 20-year-old father was six points higher than that of a child with a 50-year-old father, but adjustments reduced the difference to three points. Researchers say that gap is statistically significant, but is modest in practical terms [Science News].
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Researchers have peeked inside the brains of religious people responding to statements about God, and found that there’s no discrete part of the brain that handles religious beliefs–there’s no “God spot,” as other neuroscientists have suggested. The new study found that the neural activity in the subjects’ brains corresponded to brain networks known to have other, nonreligious functions…. “There is nothing segregated or conserved or special about religious beliefs, compared to other belief systems,” [lead researcher Jordan] Grafman said. The networks activated by religious beliefs overlap with those that mediate political beliefs and moral beliefs, he said [The New York Times].
The test subjects were read different types of statements dealing with God and religion while their brains were scanned with an fMRI machine, which measures blood flow to different parts of the brain. The scans showed that religious thoughts “light up” the areas of our brain which have evolved most recently, such as those involved in imagination, memory and “theory of mind” – the recognition that other people and living things can have their own thoughts and intentions [New Scientist].
Some researchers have hypothesized that religious beliefs are a byproduct of the neural networks used in theory of mind, suggesting that humans first evolved to imagine what other people are feeling, even people who aren’t present — and from there it was a short step to positing supernatural beings [Wired].
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