Blindness and Sensory Perception

Ever since studying Oedipus Rex and The Odyssey in tenth-grade English class, I’ve been exposed to the idea of the blind seer. From at least the heyday of ancient Greece, people have thought that with loss of sight comes a heightening of other senses (which, in literature, means extraordinary perception and foresight, usually resulting in tragedy. Oedipus, do you really want Tiresias to tell you who killed your father?).

Recent research has found that many blind people do, in fact, experience a heightened sense of touch. But this may not occur merely due to blindness, but from increased use.  

Scientists at McMaster University tested 28 profoundly blind people and compared them to 55 seeing adults. When asked to identify the textured patterns pushed against their fingertips, blind participants performed better than sighted participants. Braille readers performed better still, especially when researchers tested their reading finger.

But when the textured patterns were pushed against the participants lower lips, there was no difference in the performance of participants. Therefore, concludes the study authors, use improves skill.

How can blindness impact the other senses?

Let’s look at smell: A study from researchers at the University of Copenhagen compared the olfactory responses of normally sighted study subjects to those blind from birth. Functional magnetic resonance imaging revealed more blood flow to primary and secondary olfactory areas in the congenitally blind subjects. A study from the University of Montreal—comparing odor detection abilities of 11 congenitally blind and 14 normally sighted study subjects—concluded that the blind participants had better senses of smell only in areas relating to environmental assessment.

Compensatory sensory perception appears to result from use, which can lead the brain’s connections to change and reorganize. A “third eye” of the blind may therefore exist in some neuroplastic fashion—but not in the way presented by Sophocles and Homer.

–Johanna Goldberg

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