How do the blind walk in a straight line?

Mythbusters did a show tonight that demonstrates blindfolded people will walk, swim, and even drive in circles or a corkscrew pattern.

In the ultimate act of stupidity the Mythbusters totally ignored the blind members of our world.

Obviously they can walk in a straight line unassisted. I see them all the time walking to the stores and running errands.

Is someone born blind better at walking in a straight line then someone that lost sight as an adult?

How do the blind learn to walk in a straight line without sight?

At my college there was a blind girl who could easily swim straight laps… that was pretty amazing.

Apparently they’re relying on external cues, though (or possibly by being legally but not totally blind), because they can’t manage it totally on internal signals. The Naked Scientists fielded that question:

Experience. The visually impaired may be taught techniques that help plus having done it for years. Some visually impaired reinvent the wheel, but others take advantage of what is called orientation and moility.

I thought they may adjust their stride to compensate. But wasn’t sure how they’d do it.

Partly the blind make it work by assuming that things are laid out in straight lines. If you go down a hallway or a sidewalk using a cane to avoid walls, curbs, etc. then you’re going straight because we build those things straight.

In some circumstances, they might rely on auditory cues. I’ve heard from blind people who can tell hear when they pass doors or intersections in a hallway because those spaces echo differently.

Natural selection. They’re the only ones that make it out of drewtwo99’s dome.

Human echolocation.

Have experiments been done to determine if blinded straight-line walking is possible in other animals?