Mary Bates explains:
In essence, when blind people hear the actions of others, they use the same network of cortical brain areas that sighted people use when they observe such actions. This fits into what we already know about how some regions of the brain are recruited for different uses by blind people. For example, congenitally blind individuals rely on areas in the visual cortex to acquire information about an object’s shape and movement through other senses like touch and hearing. As Ricciardi, Pietrini and colleagues point out, the recruitment of visual brain areas for nonvisual recognition in congenitally blind individuals indicates that neither visual experience nor visual imagery is required to form an abstract representation of objects.