Spatial reasoning

A new study used motion-tracking technology to reveal the secrets behind magicians' tricks. Getty Images

Behind Abracadabra

Magicians fool us with sleight of hand, which includes pretending to handle an object that isn't there. A new study used recently developed motion-tracking technology to reveal a little of how they do it.

Researchers fitted 10 non-magicians and 10 magicians with electromagnetic tracking markers on their fingers and special shutter glasses, and asked the subjects to pick up a wooden block from a table. They then asked them to mime picking up an imaginary block beside it. In both cases, as the subjects started reaching, the glasses obscured their sight, simulating a magician's technique of turning away from the object. Motion tracking showed that the non-magicians' grasping technique changed, but the magicians kept the same technique in both cases.

Participants were then asked to pick up a battery and to mime picking up an imaginary one—but before they could, the real battery was removed. This time the magicians did no better at grasping the imaginary battery than the non-magicians. This result suggests that magicians use visual input from real objects to calibrate their grasp of imaginary ones, and because their movements are so seamless, our eyes usually fail to catch the trick. The researchers believe that magicians can do this because of greater flexibility in a part of their brain associated with spatial reasoning.

"The Magic Grasp: Motor Expertise in Deception," Cristiana Cavina-Pratesi, Gustav Kuhn, two other authors, PLoS ONE (2011)

The Rap on Memory

Neuroscientists have a sense of humor, naming a study RUN DMC (Radbound University Nijmegen Diffusions tensor and Magnetic resonance imaging Cohort study). Redferns/Getty Images

Yes, neuroscientists have a sense of humor, naming a study RUN DMC (Radbound University Nijmegen Diffusions tensor and Magnetic resonance imaging Cohort study). The serious subject: how the quality of white matter in the brain affects verbal memory.

White matter—one of the brain's two main components, along with gray matter—often degenerates with age, and this change may spur memory impairment, dementia, depression and failing motor function. Over time, cardiovascular disease can limit blood flow to the brain, resulting in mild strokes and harming the white matter.

The 503 elderly participants in this large neuroimaging study all had "cerebral small-vessel disease" and lesions in their white matter. How well they did on a simple verbal memory task strongly correlated with the quality of white matter in their hippocampus, a part of the brain central to memory.

"Diffusion Tensor Imaging of the Hippocampus and Verbal Memory Performance: The RUN DMC Study," A.G. van Norden, K.F. de Laat, eight other authors, Human Brain Mapping (March)

Metaphors Matter

Most of us think little of throwing around metaphors in conversation, but a study shows how powerful they can be.

Researchers at Stanford sought to demonstrate how metaphors can change the way we think about a problem like crime. They asked 1,482 students to read one of two reports about a crime in a particular city and to suggest solutions. In the first report, crime was described as a "wild beast preying on the city." The second report was identical, except it described crime as a "virus infecting the city."

After reading the first report, 75% of participants suggested law enforcement and punishment as the solution, including building more prisons and bringing in the military when necessary. Only 25% suggested social or economic reforms. After reading the second report, 56% suggested enforcement and punishment, and 44% suggested social reforms. Researchers found that if the metaphor appeared early in the report, and thus framed the content, it swayed opinion. Placed at the end, it had no effect.

"Metaphors We Think With: The Role of Metaphor in Reasoning," Paul H. Thibodeau and Lera Boroditsky, PloS ONE (2011)

Happy Kid, Happy Adult?

A happy child may predict a contented adult. Getty Images

The child is father of the man, said William Wordsworth, and a recent study would agree: A happy child may predict a contented adult.

Researchers at Cambridge University looked at the early and teen years of 2,776 adult subjects, analyzing their childhood mental well-being and personality (assessed from school records and personality tests, among other sources). They then correlated this information with their adult subjects' education level, marital status, income, occupation, mental health, social involvement and leadership activities.

Compared with children who had no positive ratings, participants with one positive childhood rating (e.g., a glowing teacher's report) were 21% less likely to develop emotional problems as adults, while those with two or more positive ratings were 61% less likely to develop those problems.

Surprisingly, however, happy children were no more likely to get married in adulthood, and they were more likely to get divorced.

"Do Positive Children Become Positive Adults? Evidence from a Longitudinal Birth Cohort Study," Marcus Richards and Felicia A. Huppert, Journal of Positive Psychology (January)