A few years ago I had a phone conversation with Michael Chorost, the author of Rebuilt: How Becoming Part Computer Made Me More Human. The fact that we were talking to each other over a distance of 3000 miles was incredible enough (although we take telephones for granted) but what was even more astonishing was that I was talking to a man who is profoundly deaf. Thanks to his cochlear implant, a device in his inner ear that feeds sound information to his auditory nerve, Chorost could hear me just fine.
When Michael Chorost first received his cochlear implant, people's voices sounded more like beeps and whistles than human speech. But over time, Chorost learned to interpret the input. This did not come automatically. In his book and blog, Chorost describes how he taught himself to hear again, for example, by listening to tapes of children's stories while reading along in the books. He writes that this accomplishment, unlike hearing in a baby, was "an intensely conscious act."
An intensely conscious act - I love that phrase because it describes exactly what it was like for me to gain 3D vision. All my life, I was cross-eyed: I looked through one eye and turned in the other. Through optometric vision therapy, I was made aware of how I saw and only then was I able to change the way that I used my eyes. Only then could I teach myself to aim both eyes simultaneously at the same point and see in stereo. It took great awareness and concentration to change my habits and the way I'd always negotiated the world. Fortunately, this level of concentration did not have to last forever. Once I developed a new, more efficient, and more informative way of seeing, new habits replaced the old.