For longer versions of these and other
body & brain stories, visit www.sciencenews.org
rock at physics
Below is a side view of a ball that could roll down either
the red or blue ramp. Which route do you think would
result in it arriving at the finish line first?
By Bruce Bower
Skateboarders know some righteous
physics, dude. That’s because their hair-raising rides provide body-based insights
into slope speeds that often elude others.
A ball travels faster down a relatively
long incline angling steeply downward in
two sections separated by a flat stretch
compared with a shorter incline angling
downward modestly but without changing slope. Most people don’t realize this,
but skateboarders often do, said psychologist Michael McBeath of Arizona
State University. Skateboarders call on
motor memory to determine intuitively
that a sharp early descent creates a speed
advantage, he reported November 5.
Of 122 college students shown drawings of a longer, steeply angled incline
When asked to solve the physics
problem illustrated here, skateboarders
were more likely than others to answer
correctly: the ball will reach the finish faster if it rolls
down the blue ramp. Only 27 percent of college students
got it right, but 61 percent of skateboarders did.
and a shorter, straight incline, only 27
percent realized that a ball would travel
faster down the longer path, McBeath
and his colleagues found. Intriguingly,
a few students known to be avid skateboarders solved the problem correctly.
McBeath’s team then recruited
41 volunteers — mostly males who had
skateboarded for anywhere from about
six months to 15 years— at a nearby
skateboarding park. One area of the park
contained adjacent slopes, one flat and
one with a pair of bumps, much as in the
classroom problem. Participants told to
skateboard as fast as possible down one
of these slopes picked the bumpy path
on 75 percent of runs. The bumpy slope
consistently produced faster rides.
Listening gets in the way of hearing
tracking a conversation can block out peripheral sounds
By Bruce Bower
Good listeners inadvertently turn a
deaf ear to unexpected sounds. Attending closely to a conversation creates a
situation in which unusual, clearly audible background utterances frequently go
This finding takes the famous “
invisible gorilla effect” from vision into the
realm of hearing, psychologist Polly
Dalton of the University of London
reported November 4.
More than a decade ago, researchers
observed that about half of volunteers
watching a videotape of people passing
a basketball fail to see a gorilla-suited
person walking through the group if
the viewers are instructed to focus on
counting how many times the ball gets
passed (SN: 5/21/11, p. 16).
Participants were assigned to pay
attention either to the men’s or the
Nearly all of the volunteers following the women and almost one-third
of those tracking the men didn’t hear
gorilla man at all. The intrusive ape
passed closer to the conversing men in
the acoustic scene, partly explaining
why his voice was detected more often
by those listening to the men, Dalton
Psychologist Jeremy Wolfe of Harvard
Medical School said he suspects that,
given the power of focused attention
to erase peripheral sounds, volunteers
would fail to hear gorilla man even if the
unseen primate made gorilla sounds or
played a flute.
That’s the kind of experiment that will
make some noise in the wake of gorilla
man’s first silent stroll.