Gesturing While Talking Helps Change Your Thoughts

Gesturing While Talking Helps Change Your Thoughts

  9:47:00 AM    Science Lover

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Sometimes it’s almost impossible to talk without using your hands. These gestures seem to be important to how we think. They provide a visual clue to our thoughts and, a new theory suggests, may even change our thoughts by grounding them in action.

Sometimes it's almost impossible to talk without using your hands. These gestures seem to be important to how we think. They provide a visual clue to our thoughts and, a new theory suggests, may even change our thoughts by grounding them in action. (Credit: iStockphoto/Franz Pfluegl)

University of Chicago psychological scientists Sian Beilock and Susan Goldin-Meadow are bringing together two lines of research: Beilock’s work on how action affects thought and Goldin-Meadow’s work on gesture. After a chat at a conference instigated by Ed Diener, the founding editor of Perspectives on Psychological Science, they designed a study together to look at how gesture affects thought.

For the study, published in Psychological Science, a journal of the Association for Psychological Science, Beilock and Goldin-Meadow had volunteers solve a problem known as the Tower of Hanoi. It’s a game in which you have to move stacked disks from one peg to another. After they finished, the volunteers were taken into another room and asked to explain how they did it. (This is virtually impossible to explain without using your hands.) Then the volunteers tried the task again. But there was a trick: For some people, the weight of the disks had secretly changed, such that the smallest disk, which used to be light enough to move with one hand, now needed two hands.

People who had used one hand in their gestures when talking about moving the small disk were in trouble when that disk got heavier. They took longer to complete the task than did people who used two hands in their gestures—and the more one-handed gestures they used, the longer they took. This shows that how you gesture affects how you think; Goldin-Meadow and Beilock suggest that the volunteers had cemented how to solve the puzzle in their heads by gesturing about it (and were thrown off by the invisible change in the game).



In another version of the experiment, published in Perspectives in Psychological Science, the volunteers were not asked to explain their solution; instead, they solved the puzzle a second time before the disk weights were changed. But moving the disks didn’t affect performance in the way that gesturing about the disks did. The people who gestured did worse after the disk weights switched, but the people who moved the disks did not—they did just as well as before. “Gesture is a special case of action. You might think it would have less effect because it does not have a direct impact on the world,” says Goldin-Meadow. But she and Beilock think it may actually be having a stronger effect, “because gesturing about an act requires you to represent that act.” You aren’t just reaching out and handling the thing you’re talking about; you have to abstract from it, indicating it by a movement of your hands.

In the article published in Perspectives in Psychological Science, the two authors review the research on action, gesture, and thought. Gestures make thought concrete, bringing movement to the activity that’s going on in your mind.

This could be useful in education; Goldin-Meadow and Beilock have been working on helping children to understand abstract concepts in mathematics, physics, and chemistry by using gesture. “When you’re talking about angular momentum and torque, you’re talking about concepts that have to do with action,” Beilock says. “I’m really interested in whether getting kids to experience some of these actions or gesture about them might change the brain processes they use to understand these concepts.” But even in math where the concepts have little to do with action, gesturing helps children learn—maybe because the gestures themselves are grounded in action.

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Large Study Shows : Females Are Equal to Males in Math Skills

Large Study Shows : Females Are Equal to Males in Math Skills

  9:58:00 AM    Science Lover

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The mathematical skills of boys and girls, as well as men and women, are substantially equal, according to a new examination of existing studies in the current online edition of journal Psychological Bulletin.

Young women studying mathematics. The mathematical skills of boys and girls, as well as men and women, are substantially equal, according to a new examination of existing studies.

One portion of the new study looked systematically at 242 articles that assessed the math skills of 1,286,350 people, says chief author Janet Hyde, a professor of psychology and women's studies at the University of Wisconsin-Madison.

These studies, all published in English between 1990 and 2007, looked at people from grade school to college and beyond. A second portion of the new study examined the results of several large, long-term scientific studies, including the National Assessment of Educational Progress.

In both cases, Hyde says, the difference between the two sexes was so close as to be meaningless.

Sara Lindberg, now a postdoctoral fellow in women's health at the UW-Madison School of Medicine and Public Health, was the primary author of the meta-analysis in Psychological Bulletin.

The idea that both genders have equal math abilities is widely accepted among social scientists, Hyde adds, but word has been slow to reach teachers and parents, who can play a negative role by guiding girls away from math-heavy sciences and engineering. "One reason I am still spending time on this is because parents and teachers continue to hold stereotypes that boys are better in math, and that can have a tremendous impact on individual girls who are told to stay away from engineering or the physical sciences because 'Girls can't do the math.'"

Scientists now know that stereotypes affect performance, Hyde adds. "There is lots of evidence that what we call 'stereotype threat' can hold women back in math. If, before a test, you imply that the women should expect to do a little worse than the men, that hurts performance. It's a self-fulfilling prophecy.

"Parents and teachers give little implicit messages about how good they expect kids to be at different subjects," Hyde adds, "and that powerfully affects their self-concept of their ability. When you are deciding about a major in physics, this can become a huge factor."

Hyde hopes the new results will slow the trend toward single-sex schools, which are sometimes justified on the basis of differential math skills. It may also affect standardized tests, which gained clout with the passage of No Child Left Behind, and tend to emphasize lower-level math skills such as multiplication, Hyde says. "High-stakes testing really needs to include higher-level problem-solving, which tends to be more important in jobs that require math skills. But because many teachers teach to the test, they will not teach higher reasoning unless the tests start to include it."

The new findings reinforce a recent study that ranked gender dead last among nine factors, including parental education, family income, and school effectiveness, in influencing the math performance of 10-year-olds.

Hyde acknowledges that women have made significant advances in technical fields. Half of medical school students are female, as are 48 percent of undergraduate math majors. "If women can't do math, how are they getting these majors?" she asks.

Because progress in physics and engineering is much slower, "we have lots of work to do," Hyde says. "This persistent stereotyping disadvantages girls. My message to parents is that they should have confidence in their daughter's math performance. They need to realize that women can do math just as well as men. These changes will encourage women to pursue occupations that require lots of math."

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

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Tie Light in Knots by Physicists

Tie Light in Knots by Physicists

  2:05:00 AM    Science Lover

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The remarkable feat of tying light in knots has been achieved by a team of physicists working at the universities of Bristol, Glasgow and Southampton, UK, reports a paper in Nature Physics this week.

The colored circle represents the hologram, out of which the knotted optical vortex emerges. (Credit: Image courtesy of University of Bristol)

Understanding how to control light in this way has important implications for laser technology used in wide a range of industries.

Dr Mark Dennis from the University of Bristol and lead author on the paper, explained: "In a light beam, the flow of light through space is similar to water flowing in a river. Although it often flows in a straight line -- out of a torch, laser pointer, etc -- light can also flow in whirls and eddies, forming lines in space called 'optical vortices'.

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Bacteria Shed Light on Human Decision-Making?

Bacteria Shed Light on Human Decision-Making?

  10:00:00 PM    Science Lover

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Scientists studying how bacteria under stress collectively weigh and initiate different survival strategies say they have gained new insights into how humans make strategic decisions that affect their health, wealth and the fate of others in society.

Colonies of billions of Bacillus subtilis bacteria exhibit the complex structures that sometimes form under environmental stress. (Credit: Eshel Ben Jacob)

Their study, recently published in the early online edition of the journal Proceedings of the National Academy of Sciences, was accomplished when the scientists applied the mathematical techniques used in physics to describe the complex interplay of genes and proteins that colonies of bacteria rely upon to initiate different survival strategies during times of environmental stress. Using the mathematical tools of theoretical physics and chemistry to describe complex biological systems is becoming more commonplace in the emerging field of theoretical biological physics.

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World Record In Packing Puzzle Set In Tetrahedra Jam: Better Understanding Of Matter Itself?

World Record In Packing Puzzle Set In Tetrahedra Jam: Better Understanding Of Matter Itself?

  5:21:00 PM    Science Lover

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Finding the best way to pack the greatest quantity of a specifically shaped object into a confined space may sound simple, yet it consistently has led to deep mathematical concepts and practical applications, such as improved computer security codes.

Princeton researchers have beaten the present world record for packing the most tetrahedra into a volume. Research into these so-called packing problems have produced deep mathematical ideas and led to practical applications as well.
(Credit: Princeton University/Torquato Lab)

When mathematicians solved a famed sphere-packing problem in 2005, one that first had been posed by renowned mathematician and astronomer Johannes Kepler in 1611, it made worldwide headlines.

Now, two Princeton University researchers have made a major advance in addressing a twist in the packing problem, jamming more tetrahedra -- solid figures with four triangular faces -- and other polyhedral solid objects than ever before into a space. The work could result in better ways to store data on compact discs as well as a better understanding of matter itself.

In the cover story of the Aug. 13 issue of Nature, Salvatore Torquato, a professor in the Department of Chemistry and the Princeton Institute for the Science and Technology of Materials, and Yang Jiao, a graduate student in the Department of Mechanical and Aerospace Engineering, report that they have bested the world record, set last year by Elizabeth Chen, a graduate student at the University of Michigan.

Using computer simulations, Torquato and Jiao were able to fill a volume to 78.2 percent of capacity with tetrahedra. Chen, before them, had filled 77.8 percent of the space. The previous world record was set in 2006 by Torquato and John Conway, a Princeton professor of mathematics. They succeeded in filling the space to 72 percent of capacity.

Beyond making a new world record, Torquato and Jiao have devised an approach that involves placing pairs of tetrahedra face-to-face, forming a "kissing" pattern that, viewed from the outside of the container, looks strangely jumbled and irregular.

"We wanted to know this: What's the densest way to pack space?" said Torquato, who is also a senior faculty fellow at the Princeton Center for Theoretical Science. "It's a notoriously difficult problem to solve, and it involves complex objects that, at the time, we simply did not know how to handle."

Henry Cohn, a mathematician with Microsoft Research New England in Cambridge, Mass., said, "What's exciting about Torquato and Jiao's paper is that they give compelling evidence for what happens in more complicated cases than just spheres." The Princeton researchers, he said, employ solid figures as a "wonderful test case for understanding the effects of corners and edges on the packing problem."

Studying shapes and how they fit together is not just an academic exercise. The world is filled with such solids, whether they are spherical oranges or polyhedral grains of sand, and it often matters how they are organized. Real-life specks of matter resembling these solids arise at ultra-low temperatures when materials, especially complex molecular compounds, pass through various chemical phases. How atoms clump can determine their most fundamental properties.

"From a scientific perspective, to know about the packing problem is to know something about the low-temperature phases of matter itself," said Torquato, whose interests are interdisciplinary, spanning physics, applied and computational mathematics, chemistry, chemical engineering, materials science, and mechanical and aerospace engineering.

And the whole topic of the efficient packing of solids is a key part of the mathematics that lies behind the error-detecting and error-correcting codes that are widely used to store information on compact discs and to compress information for efficient transmission around the world.

Beyond solving the practical aspects of the packing problem, the work contributes insight to a field that has fascinated mathematicians and thinkers for thousands of years. The Greek philosopher Plato theorized that the classical elements -- earth, wind, fire and water -- were constructed from polyhedra. Models of them have been found among carved stone balls created by the late Neolithic people of Scotland.

The tetrahedron, which is part of the family of geometric objects known as the Platonic solids, must be packed in the face-to-face fashion for maximum effect. But, for significant mathematical reasons, all other members of the Platonic solids, the researchers found, must be packed as lattices to cram in the largest quantity, much the way a grocer stacks oranges in staggered rows, with successive layers nestled in the dimples formed by lower levels. Lattices have great regularity because they are composed of single units that repeat themselves in exactly the same way.

Mathematicians define the five shapes composing the Platonic solids as being convex polyhedra that are regular. For non-mathematicians, this simply means that these solids have many flat faces, which are plane figures, such as triangles, squares or pentagons. Being regular figures, all angles and faces' sides are equal. The group includes the tetrahedron (with four faces), the cube (six faces), the octahedron (eight faces), the dodecahedron (12 faces) and the icosahedron (20 faces).

There's a good reason why tetrahedra must be packed differently from other Platonic solids, according to the authors. Tetrahedra lack a quality known as central symmetry. To possess this quality, an object must have a center that will bisect any line drawn to connect any two points on separate planes on its surface. The researchers also found this trait absent in 12 out of 13 of an even more complex family of shapes known as the Archimedean solids.

The conclusions of the Princeton scientists are not at all obvious, and it took the development of a complex computer program and theoretical analysis to achieve their groundbreaking results. Previous computer simulations had taken virtual piles of polyhedra and stuffed them in a virtual box and allowed them to "grow."

The algorithm designed by Torquato and Jiao, called "an adaptive shrinking cell optimization technique," did it the other way. It placed virtual polyhedra of a fixed size in a "box" and caused the box to shrink and change shape.

There are tremendous advantages to controlling the size of the box instead of blowing up polyhedra, Torquato said. "When you 'grow' the particles, it's easy for them to get stuck, so you have to wiggle them around to improve the density," he said. "Such programs get bogged down easily; there are all kinds of subtleties. It's much easier and productive, we found, thinking about it in the opposite way."

Cohn, of Microsoft, called the results remarkable. It took four centuries, he noted, for mathematician Tom Hales to prove Kepler's conjecture that the best way to pack spheres is to stack them like cannonballs in a war memorial. Now, the Princeton researchers, he said, have thrown out a new challenge to the math world. "Their results could be considered a 21st Century analogue of Kepler's conjecture about spheres," Cohn said. "And, as with that conjecture, I'm sure their work will inspire many future advances."

Many researchers have pointed to various assemblies of densely packed objects and described them as optimal. The difference with this work, Torquato said, is that the algorithm and analysis developed by the Princeton team most probably shows, in the case of the centrally symmetric Platonic and Archimedean solids, "the best packings, period."

Their simulation results are also supported by theoretical arguments that the densest packings of these objects are likely to be their best lattice arrangements. "This is now a strong conjecture that people can try to prove," Torquato said.

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