From sensebridge.net/northpaw: "What makes it way more awesome than a regular compass? Persistence. With a regular compass the owner only knows the direction when he or she checks it. With this compass, the information enters the wearer's brain at a subconscious level, giving the wearer a true feeling of absolute direction, rather than an intellectual knowledge as with a regular compass." I wore my North Paw everyday for several months, and I didn't feel these effects until several weeks of wearing. But ultimately, *feeling* North every instant that one wears the device is fundamentally different than periodically glancing at a display and thinking about one's orientation. Whether or not a cognitively integrated haptic display is a (psuedo-)prosthesis is a claim I don't really care to support or to deny. Building the North Paw was lots of fun and wearing it has been an absolutely fascinating new way to experience the world and explore the plasticity of my brain.

If the wearer was passively registering the information from the anklet, then it would truly be only 45 degree resolution. However, when wearing it, it quickly becomes habit to twist the ankle back and forth slightly, to feel the exact point at which active motors change. This way the resolution approaches something close to the actual sensing capabilities of the compass IC (minus noise from the lag of the motors spinning up and down). It's the same unconscious action by which you might tilt something at an angle to see it's surface better. To answer the magnetic vs. true north question, the fact of the matter is that it really doesn't matter WHAT it points at. We picked (magnetic) North because that's seems a good default standard in Western culture. The usefulness of the device is in having an ever-persistent point of reference. As long as that directional reference is *consistent*, it should be able to point any cardinal direction and still be integrated into ones cognitive sphere. (Disclaimer, I'm the co-developer and have a lot of experience wearing one.)