Look and Listen

You've seen them: those trick-the-eye images of geometric objects that look different in size or that have different angles -- obviously! -- but in fact are the same. In this classic image, for example, the objects have approximately the same 90 degree angles.

Now you can peek behind the curtain as Duke Medical Center neuroscientist Dale Purves (photo) shows how you are fooled. On a website straight out of Oz, he and his laboratory mates reveal -- in compelling sight and sound -- how humans see and hear what they do. Go there -- it's a five-ticket ride.

Critics agree. The site recently was voted Best of the Web by the editors of The Scientist, in the magazine's first-ever review of laboratory websites. The judges singled out the site's "excellent interactive graphics" and its "engaging way of presenting difficult concepts." But as a downside, one visitor who nominated the site cautioned: "Be prepared to lose at least a half hour!"

As to the science behind the scenes, Dr. Purves and his colleagues -- including Beau Lotto and Mark Williams, who designed the website and created many of its graphics -- have devised a theory that as Duke Magazine has reported:

...challenges the cherished belief that our visual brains are logically organized, analytical machines that provide a neural blueprint for interpreting images. The result of their exacting work: a theory that vision is basically a reflex no different than the knee-jerk response produced when the doctor taps your knee with a rubber hammer.

While visiting the lab's website, explore some of the mysteries of music and the harmonics of human vocalization, which Dr. Purves and his band also study. In fact, their work was recently hailed by Discover magazine as one of the top 100 science stories of 2007; see here and here. A video of Dr. Purves and student Jonathan Choi explaining one recent finding can be viewed here or below.