We headed to the Center for Human-Computer Interaction “Black Lab” at the CRC KnowledgeWorks II building to use the OptiTrak motion tracking system.

The OptiTrack is basically a set of infrared cameras that track little reflective balls glued to a pair of empty glasses frames and to a cleverly-designed bunch of tongue depressors. You might be able to make out some of the cameras above Stephanie in this photo.

The ability to walk a path with one's eyes closed is called “path integration.” We played “path integration pictionary” by closing our eyes and trying to walk out paths that looked like randomly-selected items. The OptiTrak captured our motion paths.

Here's a video of Adon's turn:

Adon walking

So far Riley is winning, from her masterful performance of “bird.” Adon gets credit for guessing it.

Here are the bird's eye view plots of some of the other entries:

Riley's winning entry:

Adon's entry (the plot is set up so that the bottom corresponds to where Adon started walking)

(Anthony's guess: a pretty flower)

(James claimed that he was going to guess a balloon, which is the right answer, but no points)

Stephanie's intriguing entry:

(Anthony's guess: a bunny head; or: a biting dinosaur, rotated 45°)

Stephanie says: You are right! My word was rabbit so I drew a bunny head. :)

Anthony's mangled entry:

(Anthony says: sorry, this doesn't look remotely like what I would have drawn with my hands. Curse you, parietal lobe!)

Stephanie guesses: Donut?

(Anthony says: that is a great guess, but unfortunately I had no idea that I was walking in a donut-shaped path)

(The answer is: a drum.

Other guesses were: Africa, a toilet seat, a TV, a tunnel).