Synesthesia

For decades, scientists who heard about synesthesia hearing colors,
tasting words, seeing colored pain just shrugged their shoulders or rolled their
eyes. Now, as irrefutable evidence mounts that some healthy brains really do this,
we are forced to ask how this squares with some cherished conceptions of
neuroscience. These include binding, modularity, functionalism, blindsight, and
consciousness. The good news is that when old theoretical structures fall, new light
may flood in. Far from a mere curiosity, synesthesia illuminates a wide swath of
mental life.

In this classic text, Richard Cytowic quickly
disposes of earlier criticisms that the phenomenon cannot be "real," demonstrating
that it is indeed brain-based. Following a historical introduction, he lays out the
phenomenology of synesthesia in detail and gives criteria for clinical diagnosis and
an objective "test of genuineness." He reviews theories and experimental procedures
to localize the plausible level of the neuraxis at which synesthesia operates. In a
discussion of brain development and neural plasticity, he addresses the possible
ubiquity of neonatal synesthesia, the construction of metaphor, and whether everyone
is unconsciously synesthetic. In the closing chapters, Cytowic considers
synesthetes' personalities, the apparent frequency of the trait among artists, and
the subjective and illusory nature of what we take to be objective reality,
particularly in the visual realm.

The second edition has been
extensively revised, reflecting the recent flood of interest in synesthesia and new
knowledge of human brain function and development. More than two-thirds of the
material is new.