Today scientists have new tools for studying synethesia. Medical imaging techniques such as positron-emission tomography scans can actually show activity in different parts of the brain. Specific brain regains process different kinds of information. When people aare given PET scans which listening to recorded words, the part of the brain associated with language shows activity. But in colored-language synthetes, so does a part of the brain that’s associated with sorting images by color. Tests like this show that synthesia is real, even if some people faked it in past.
The tests don’t explain why only some people have this ability, however. One possible answer is that the brains of synthetes are “cross-wired”. That is, nerves may connect different regions of the brain more strongly in these people than in other. An area that handles colors may be strongly linked to areas that handle language, so that hearing words activates both areas.
