Posts Tagged ‘J. Exp’

A Mental Abacus Lets Math Whizzes Bypass Language

August 9th, 2011 08:52 admin View Comments


What’s the News: Most of us need everyone to stop talking when we perform mental math. But for children trained to do math visually with a “mental abacus,” verbal disturbances roll off their backs, prompting psychologists to posit that unlike the rest of us, they aren’t routing their calculations through words.

What’s the Context:

  • While some of the most brilliant mathematicians have been known for their ability to “think in shapes,” and Einstein said he used “sensations of a kinesthetic or muscular type” to come up with his breakthroughs, math is usually taught much like reading: a system of symbols to be interpreted.
  • It’s been suggest that the mental abacus, a system in which children are taught to use a physical abacus and then learn to manipulate it mentally, uses visual, rather than verbal, brain processes, judging from fMRI studies. And it seems to work phenomenally well: the winner of the 2010 Mental Calculation World Cup was an 11-year-old girl trained in mental abacus.
  • But working memory, the ability to juggle a few things in the front of one’s mind during activities like mental math, is known to have distinct size limitations. Generally, the number of mental objects we can keep up with tops out at three or four. So how are mental abacus users doing it?

How the Heck:

  • To confirm that the mental abacus was indeed not verbal, researchers had subjects trained in mental abacus and subjects without training listen to a recording of a story while performing mental math problems and repeat each of the story’s words as they went. Since mental abacus users often twitch their fingers in the air as though moving abacus beads, which could indicate that motor memory is involved, the researchers also gave some subjects a motor task to perform at the same time or in isolation: drumming their fingers on the table.
  • They found that although untrained subjects found it almost impossible to do calculations while performing the verbal task, it perturbed the mental abacus users only slightly. Turning the tables, the motor task had no effect on untrained subjects, but it did disturb the mental abacus users to a similar, slight extent as the verbal disruption. This confirms that mental abacus users are not using verbal methods in their calculations, and suggests that motor memory might somehow be involved, though more experiments on that point are required.
  • They also found that though there was no clear ceiling on the number of numbers mental abacus users could add, their adding ability declined precipitously when the numbers had more than three digits.
  • This suggests that the limit of their working memory is kicking in not on the number of numbers they add, but on the number of columns on the abacus, where each column corresponds to a decimal place. And maybe that’s why, when we’re stuck in the verbal traffic jam of “three hundred and eight plus seven thousand thirty-four,” they’ve already arrived at the answer.

Reference: Frank MC, Barner D. Representing exact number visually using mental abacus. J Exp Psychol Gen. 2011 Jul 18. Click here for a pdf of the text from the researchers.

Image: mmt2000 / flickr

Source: A Mental Abacus Lets Math Whizzes Bypass Language

Evolution of Flight: Did Early Birds Run and Flap Before They Flew?

June 24th, 2011 06:03 admin View Comments

Flapping while running up a ramp takes far
less energy than flight at the same angle.

What’s the News: How did birds get their wings? And how did they start using them to fly? These questions have bedeviled evolutionary biologists for more than a century, and with flight’s origins long buried, a lot of careful measurements of how modern birds work combined with clever guesswork has resulted in several fiercely differing theories. The two major camps have proto-birds either dropping from trees or running along the ground before finally taking to the air.

A new study lends credence to the idea that flapping wings while running could have been involved by showing that it requires much less energy than flying while still helping birds get over obstacles. This suggests that it could have been an easy way for proto-birds to start going through the motions.

How the Heck:

  • The researchers had noticed that young birds running up ramps and other obstacles flap their wings strongly, gaining speed and balance. The team wondered how much energy the process took: as the behavior gets birds over obstacles as effectively as actual flight, if it took less investment of energy, it could have been a flight stepping stone accessible to early birds.
  • They trained adult pigeons to run up nearly vertical ramps as well as fly to perches from the ground, requiring a similar angle of ascent, and then implanted sensors in their flight muscles. When they recorded how much energy each took, they found that running took less than 10% of the energy of flight. This confirmed that flapping while running up obstacles could have been a plausible intermediate stage in flight’s evolution, and could have been performed even with fairly small muscles, such as those in early birds.

What’s the Context:

  • The two primary competing theories, arboreal (tree-dropping) and cursorial (running along the ground), imply totally different lifestyles for early birds. Thus, a lot of the debate over these models, which were first suggested in the 1880s, revolves around what bird-like fossils like the feathered Archaeopteryx reveal in terms of tree-climbing or running ability. But interpretations of the structure of its bones, claws, feathers, and probable musculature differ considerably.
  • The evolution of feathers has likewise been drawn into the fray, as when they arose, and which ones, pinions or secondaries, came first, matters in models of early flight (see here for a detailed discussion of both models and the evolution of feathers).
  • Ken Dial, the senior author of the new study, came up with the idea that studying how young birds learn to fly could give scientists insight into how flight evolved in the first place. While there’s a whiff of recapitulation theory there (the now-discounted idea that a creature’s development recapitulates its evolution), in terms of physics, the pre-flight motions of young birds are one of the few ways scientists can get a look at what might have happened at a point when creatures had wings but did not yet fly.
  • Though the involvement of running seems to place this work in the cursorial camp, Dial, citing problems with both the major models, has said that he sees his work striking off in another direction. “I would argue that studying the proto-wings of juvenile, still-developing birds might provide a useful avenue by which to approach the problem of the earliest flyers,” he says (via CABINET). “Rather than concentrating on the arboreal/cursorial divide, I think it might be more fruitful to focus on questions like these, such as how does the flight stroke itself develop, what structures make it possible, and what purposes can they serve at differing levels of efficiency.”

The Future Holds: As long as time travel is impossible, studying the physics of modern birds and comparing them with fossils is the most effective way to learn about the evolution of flight. Expect more experiments dealing with the mechanics of flight, as researchers focus more and more on detailed aerodynamics in sussing out flight’s origins.

Reference: Jackson, B. E., Tobalske, B. W. and Dial, K. P. (2011) The broad range of contractile behaviour of the avian pectoralis: functional and evolutionary implications. J. Exp. Biol. 214, 2354-2361.

Image credit: Dial, K.P., J. Exp. Biol.

Source: Evolution of Flight: Did Early Birds Run and Flap Before They Flew?