Citation

Botvinick-Greenhouse J, Shinbrot T. Phys. Today 2020; 73(2): 62-63.

Copyright

(Copyright © 2020, American Institute of Physics)

DOI

10.1063/PT.3.4417

PMID

unavailable

Abstract

In 1993 Claude Shannon, founder of information theory, wrote a popular analysis of juggling, and he even accompanied the article with a working model of a juggling robot. Building such a robot--in fact, juggling at all--is remarkable, because it seems to require faster reaction times than most of us can muster. Speed jugglers can achieve nearly 500 catches in a minute, a rate that allows just 120 ms per catch. Yet typical human reaction times are 250 ms, and even experts in high-speed sports such as tennis take 200 ms to adjust their responses.

So how do jugglers with reaction times no better than 200 ms catch balls every 120 ms? In part, multitasking may allow multiple balls to be processed simultaneously, though how that is done with 11 balls--the Guinness world record--is far from clear. And in part, balls are not thrown to random locations, so each ball need not be tracked and caught independently. Indeed, up to five balls can be juggled while the juggler is blindfolded. Jugglers rely on making accurate throws and predictions of where the balls will travel. The accuracy required is a measure of how unstable--and thus how difficult--a particular juggling pattern is.