Juggling
Teaches Brain New Tricks
Learning
How to Juggle Changes Brain Structure
By
Jennifer Warner
WebMD Medical News Reviewed By Brunilda Nazario,
MD
on Wednesday, January 21, 2004
Jan. 21, 2004 -- An old brain may not be too
old to learn new tricks after all.
A new study shows learning how to juggle can
actually change the structure of the brain
in adults and increase areas involved in thought
and processing.
Researchers say the findings challenge the
notion that the structure of the adult brain
does not change except for negative changes
caused by aging or disease. Instead, the study
suggests that learning produces not only functional
but structural changes in the brain.
Juggling Boosts Brain Power
In
order to see if the structure of the adult
brain changes in response to demands, researchers
used magnetic resonance imaging (MRI) scans
to look at the brains of adults who have learned
to juggle.
In the study, published in the Jan. 22 issue
of Nature, researchers divided a group of
young adults who had no experience in juggling
into two groups. One group was given three
months to learn how to juggle three balls
simultaneously, and the others remained non-jugglers.
MRI scans were performed at the start of the
study, after the jugglers became skilled performers
and could juggle for at least 60 seconds,
and three months later. During that three-month
period, the jugglers did not practice or attempt
to extend their skills.
Although the participants had similar brain
scans at the start of the study, the second
scan revealed that the jugglers experienced
significant expansion in the area of the brain
associated with the processing and storage
of complex visual motion.
The amount of expansion also correlated with
the juggler's performance. The more skilled
they became, the greater growth they experienced.
The increased areas seen on brain scans among
the jugglers declined by the third brain scan.
The non-jugglers showed no change in brain
structure during the study.
Researchers say the temporary brain structure
changes occurred in motion-selective areas
of the brain, and the mechanism behind these
changes is unclear and merits further study.
A
PAPER ON SPEED V. ACCURACY
By
Jack Kalvan
I
tested over 100 people ranging from non-jugglers
to some of the best jugglers in the world.
Every one of the test subjects had the hand
speed to juggle 9 balls.
The average was about 16 balls, and the highest
recorded was about 24 balls.
Hand speed did tend to increase slightly with
juggling ability.
Those who said they had flashed 9 or more balls
averaged about 18.3,
while those who had never flashed 5 balls averaged
about 14.4.
hand
speed averaged highest for people around 18
years old;
there was a small decrease in hand speed with
age; and
males tended to get slightly higher readings
than females.
Often
there was a difference between the two hands
and many were surprised to find they did better
with their "bad" hand.
I
suspect that some of the test subjects were
not trying as hard as they could have.
Also I suspect some could have done better by
relaxing their arms more – it helped me.
Conclusions
Every
person I tested demonstrated the hand acceleration
needed to juggle a smooth 9 ball cascade. Unfortunately,
catching wild throws in a messy, inaccurate
9 ball cascade requires much more acceleration
than this.
Very few of the test subjects have the accuracy
to juggle 9 balls smoothly.
By
practicing, one's accuracy improves, the demands
on one's acceleration are lessened, and the
juggling actually requires less and less effort.
If
one makes a throw too far across and has to
move the catching hand twice the usual horizontal
distance in the same amount of time, this requires
twice as much horizontal acceleration.
If one's inaccuracy is in throw height, there
is an even more unfortunate relationship.
Suppose one hand makes a slightly high throw
followed by a slightly low throw, so that the
two balls come down at almost the same time.
If a throw has to be made in half the normal
time, this requires four times the vertical
acceleration.
If juggling 7 balls, this correction would probably
be beyond human capabilities.
