Most of us think we can see only with our eyes. But, the development of some recent prosthetic devices may prove otherwise. Take, for example, the vOICe system developed by Peter Meijer. This device uses a video camera mounted on a pair of sunglasses to film the landscape. The pixelated picture is then converted into sounds that are delivered to the wearer via headphones. Brighter objects sound louder, and objects higher up in the visual field are heard as pitches of higher frequency. With practice, individuals, even those who have been blind since birth, can use vOICe to locate objects. They discover how the soundscape of the object varies as they move; they experience a sense of perspective and a feeling of space and openness. In other words, their sensations seem very vision-like.

"Seeing" with vOICe is very reminiscent of the sensory substitution devices that the late Paul Bach-y-Rita developed in the 1960's. They are based on a fascinating premise. We think of the brain as modular, that is, there are specific areas of the brain devoted to sight, others devoted to hearing, and so on. But maybe our brain is simply looking for information and will use the best information out there to create a perception. Vision provides excellent spatial resolution, and the "visual" parts of the brain may be devoted to this skill. But, if vision is lost, can another sense provide this information and feed it to the visual parts of the brain?