On and Off the Grid

I'll be making a return visit to the VEN (Virtual Reality Environment) Lab at Brown University tomorrow. Bill Warren, department chair and professor of cognitive and linguistic sciences, heads up the lab. He was kind enough to let me don the VR headgear and explore the virtual worlds of his lab back in 2003 for a Boston Globe feature I wrote on navigation research (my initiation into this research). Lucky for me, I had a researcher "wrangler" following me around while I explored to keep my feet clear of the wires connecting the VR headgear to the computers, and keep my face clear of oncoming brick walls.

Since 1999, Warren has used these virtual worlds to investigate all aspects of how humans "path integrate" (i.e. how well we track our own distance and direction over time as we move, independent of landmarks). A really good path integrator should be able to follow a circuitous path and take a shortcut back "home" and should, after enough exploration, start developing an accurate sense of how far and in what direction any location in an environment is from any other--in short, a Euclidian cognitive map.

A common test of path integration skill is to have people walk two legs of a triangle in a virtual desert, then have them turn and walk the third leg back to the starting point without any visual aids. After that, the researchers often start messing around... adding landmarks to see if that changes anything, and then moving landmarks to see if you notice, etc.

Generally, Warren has found humans to be pretty bad at path integrating. Recently, he's taken aim at the theory that we're ever capable of building up a Euclidian cognitive map. He's had people learn locations and routes in a virtual hedge maze and then secretly introduced "wormholes" within the maze that magically transport people to those locations. A Euclidian cognitive map would cry foul at such geometric dislocation, says Warren, but "nobody has found anything amiss."

Tomorrow, Warren will show me the wormholes. I'll also continue trying to diagnose my own sense of direction with the help of post-doc Mintao Zhao who is looking into what happens when path-integration and landmarks compete and with doctoral student Liz Chrastil who will run me through a battery of basic skills tests and have me take part in her active-vs-passive learning experiments.