(We are republishing ‘legacy content’ from our PLOS Neuroanthropology weblog, which has been taken down, along with many of the other founding PLOS Blogs. Some of these, I am putting up because I teach with them. If you have any requests, don’t hesitate to email me at: greg.downey @ mq (dot) edu (dot) au. I suspect many of the links in this piece will be broken, but I will endeavour to try to slowly rebuild this content. I originally published this on 14 Junne, 2011. Comments have been pasted in at the end of the post from the original.)
As any fan of the adventures of Daredevil knows, being blind in comic books can give you superpowers. Matt Murdoch was blinded by a radioactive accident that he befell because he tried to save a blind pedestrian from the truck carrying the waste (ah, the irony…). Murdoch developed a kind of ‘radar’ sense that allowed him to prowl Hell’s Kitchen, rooting out the miscreants and lowlifes who, like the blind Man Without Fear, preferred to lurk in the dark.
Although his personal life proved that nice guys often finish, if not last, certainly with a heavy burden of angst and personal tragedy, Daredevil built upon the observation that deprivation of one sense can lead to heightened ability in others.
Although the Man without Fear may seem implausible, in fact, researchers have examined a number of blind individuals who seem to develop extraordinarily acute echolocation, a kind of active sonar that they use by clicking to produce echoes from their surroundings. In a recent edition of PLoS ONE, Lore Thaler from the University of Western Ontario, with Stephen Arnott and Melvyn Goodale, report on brain imaging research that tries to sort out how individuals who can echolocate – who have what one blind activist calls ‘flash sonar’ – accomplish this perception neurologically. Do they use an especially acute sense of hearing, or do they develop another kind of sense, able to transform echoes into spatial perception?
What the researchers found, in short, is that blind individuals who could echolocate did not really have better ‘hearing’; on normal tests of hearing acuity, they scored the same as two sighted subjects who could not echolocate. However, when a recording had echoes, parts of the brain associated with visual perception in sighted individuals became extremely active, as the echolocators were able to extract information from the echoes that was seemingly not accessible to the control subjects who were sighted.