Compared to some of the drugs out there, cannabis can seem relatively harmless. It doesn’t have the ruinous effects of methamphetamines or even substances like synthetic pot. But there has long been suspicion that heavy use might have long-term effects on IQ, for instance [pdf].
Factors that tend to accompany cannabis consumption, such as the use of other drugs and alcohol and, in adolescents, a tendency to skip class, have made it difficult to decisively pin a dip in IQ to marijuana use. To clear away the noise, the authors of a new study in the Proceedings of the National Academy of Sciences turned to the reams of data from the Dunedin Multidisciplinary Health and Development Study, and they’ve found that on average, by the time they reached age 38, heavy pot users diagnosed with cannabis dependence during adolescence suffered an 8-point drop in IQ.
What’s the News: America’s intelligence agencies are in the business of predicting the future, using limited amounts of information to divine world events. But even expert analysts and sophisticated algorithms can make mistakes.
That’s why IARPA—which takes on high-risk, high-reward research projects (read: awesome longshots) in US intelligence—is turning to crowdsourcing, reports Adam Rawnsley at Wired.com’s Danger Room. Applied Research Associates will launch an IARPA-backed website this Friday to test whether those of us without security clearances can point the clandestine services in the right direction.
Getting better at chess, it turns out, isn’t merely a matter of thinking harder, or using one specific area of the brain—it has more to do with the neural links between brain regions. Neuroscientists from Japan studied the brainy blood-flows of both professional and amateur shogi players (a chess-like game from Japan) and found that professionals have certain brain circuits that may allow them to put on their intuitive thinking caps.
The study, published in Science, used functional magnetic resonance imaging (fMRI) to examine which brain areas showed the most blood flow as professional and amateur shogi players tested their mettle during a match. The experts showed more activity in two regions: the precuneus region in the parietal lobe, which is involved in pattern recognition, and the caudate nucleus, an area in the basal ganglia that is involved in learning, memory, and cognition.
The research team found that the precuneus-caudate connection showed up consistently when professionals were asked to come up with a rapid-fire choice of moves, but not as much for the amateurs. “These results suggest that the precuneus-caudate circuit implements the automatic, yet complicated, processes of board-pattern perception and next-move generation in board game experts,” the researchers reported. [MSNBC]
Neanderthals, it would appear, grew up in a big hurry. In a new study in the Proceedings of the National Academy of Sciences this week, Harvard anthropologists who studied Neanderthal teeth samples say that the evidence captured in those teeth show the rate at which they developed. Compared with human children, Neanderthal kids raced though their developing years and into adulthood, the researchers say.
Tanya Smith and colleagues used advanced X-ray scans of the tooth fossils of Neanderthals and the humans who lived concurrently with them to discover the layers therein. She says such scans reveal “growth lines” that serve the same purpose as tree rings–they allow researchers to measure the individual’s development year by year, and to determine his or her exact age at death.
Even when compared to some of the earliest human teeth, taken from remains of humans who left Africa 90,000 to 100,00 years ago, the differences were clear. Human teeth grew more slowly, pointing to more leisurely periods of youth. “This indicates that the elongation of childhood has been a relatively recent development,” the study said. [AFP]
When you were born, your brain was more elongated than it is now; it rounded out into its more globular shape as you grew up and crammed it full of knowledge. Neanderthals, it appears, were born with brains in that same elongated shape. But in their case it never changed: Adult Neanderthals’ brains didn’t move to the more rounded shape like ours, according to a study now out in Current Biology.
Scientists have long known that Neanderthals had brains that were about as big as our own, but this study may help explain how their cognitive abilities differed.
[The researchers used CT scans] to study nine fossil Neandertals, including a newborn, a year—old baby, and three children. Because the brain does not fossilize, they studied endocasts, imprints of the brain left in the skull. They found that at birth, both Neandertal and modern human infants had elongated braincases that were similar in shape, although Neandertal faces were already larger. But by age 1 or so, modern humans had grown globular brains, whereas Neandertal babies had not. [ScienceNOW]
Neanderthals, in keeping the same basic brain shape throughout life, maintain the pattern of brain development seen in chimpanzees. In contrast, modern humans have evolved a unique pattern, says lead researcher Philipp Gunz:
Remember the kerfuffle over “Is Google Making Us Stupid?” The 2008 cover story in The Atlantic by Nicholas Carr contended that the barrage of information available on the Web is changing our brains, making us all shallow and deficient in our attention span. It also raised a ruckus across the blogosphere with Web users who didn’t like to be called “stupid.” Now, as if to challenge our cultural ADD, Carr has expanded that article into a book: The Shallows: What the Internet Is Doing to Our Brains.
In book reviewers, Carr finds a friendlier audience to his “more books and less Internet” thesis. The Boston Globe is impressed with the argument, if unimpressed with drawing out the argument to such a great length:
Carr’s argument rests on just three chapters (out of ten). He lays out, first, what we now know about the adult brain’s malleability, or “plasticity,’’ and then draws on a slew of recent studies to make the startling case that our increasingly heavy use of digital media is actually changing us physiologically — rewiring our neural pathways. And not necessarily for the better. “The possibility of intellectual decay,’’ Carr notes, “is inherent in the malleability of our brains.’’
Carr, promoting his book with a CNN essay, grabs neuroscience studies to bolster several claims: That people who multitask while online struggle to concentrate when they’re offline, that spending a lot of time on electronic devices hinders creative and critical thinking, and that students who surfed the Web during a lecture retained less information than those who listened with laptops closed. (That last one is kind of a “duh”—people who fill out Sudokus or read “Twilight” books during class probably don’t retain much, either.)
Much to the chagrin of a certain Wyoming Senator, the Central Intelligence Agency is poised to fight terrorism and spy on sea lions (Sen. John Barrasso once quipped the CIA should stick to the former occupation). The nation’s top scientists and spies are collaborating on an effort to use the federal government’s intelligence assets — including spy satellites and other classified sensors — to assess the hidden complexities of environmental change. They seek insights from natural phenomena like clouds and glaciers, deserts and tropical forests [The New York Times].
The program will have little impact on the CIA’s normal intelligence gathering, say those involved, and will only release data already in hand or data gathered during satellite down time. The images will even have their sharpness decreased in order to maintain some secrecy about the satellites’ true capabilities.
Researchers have more evidence that takes aim at the old stereotype that boys are better at math than girls. Psychologist Janet Hyde had previously studied scores on standardized math tests in the United States, and found no difference in performance between girls and boys. Her new study expands the scope of the work by analyzing international data. She and her colleague analyzed studies from around the world on math performance along with gender inequality as measured by the World Economic Forum’s Gender Gap Index. This index measures the gap between men and women in economic opportunity, educational attainment and other socioeconomic factors [LiveScience].
They found that countries with poor gender equality, like India, had a larger gender gap in math, while in countries with excellent gender equality, like the Netherlands, girls performed as well as boys. If males really did have an innate advantage in math, the researchers note, that advantage should be obvious throughout all these cultures. Instead, the study suggests that cultural issues are the basis of the math gender gap.
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].