A very cool discovery out of Caltech: auditory synesthesia. Synesthesia, you probably know, is an effect wherein the stimulation of one sense causes automatic sensations in another sense. For example, grapheme-color synesthesia is where numbers or letters appear to those observing to be shaded or tinged with different colors. Now two researchers at Caltech, Melissa Saenz (Who I know! I know someone who discovered something really cool!) and Christof Koch, have identified a new form of synesthesia, auditory synesthesia. To describe it, it’s funner to read what Dr. Saenz has to say about how it was discovered.
“While I was running an experiment at the Caltech Brain Imaging Center, a group of students happened to pass by on a tour, and I volunteered to explain what I was doing,” explains Saenz, who, along with Christof Koch, the Lois and Victor Troendle Professor of Cognitive and Behavioral Biology at Caltech and professor of computation and neural systems, reports the finding in the August 5 issue of the journal Current Biology.
“As part of the experiment, a moving display was running on my computer screen with dots rapidly expanding out, somewhat like the opening scene of Star Wars. Out of the blue, one of the students asked, “Does anyone else hear something when you look at that?” After talking to him further, I realized that his experience had all the characteristics of a synesthesia: an automatic sensory cross-activation that he had experienced all of his life,” says Saenz.
A search of the synesthesia literature revealed that auditory synesthesia–of any kind–had never been reported. Intrigued, Saenz began to look for other individuals with the same ability, using the original movie seen by the student as a test. “I queried a few hundred people and three more individuals turned up,” she says. Having that specific example made it easy to find more people. That movie just happens to be quite “noisy” to the synesthetes and was a great screening tool. When asked if it made a sound, one of the individuals responded, “how could it not?” I would have been less successful had I just generally asked, “Do you hear sounds when you see things move or flash?” because in the real environment, things that move often really do make a sound,” for example, a buzzing bee.
This may be why auditory synesthesia hadn’t been detected by neurobiologists. “People with auditory synesthesia may be even less likely than people with other synesthetic associations to fully realize that their experience is unusual. These individuals have an enhanced soundtrack in life, rather than a dramatically different experience, compared to others,” says Saenz. However, when asked, all of the synesthetes could name examples of daily visual events that caused sounds that they logically knew to be only in their minds, such as seeing a fluttering butterfly or watching television with the sound turned off.
Very cool stuff, I must say, and the way it was discovered is just, well its just cool, I must say. Even better, the researchers believe that the effect may be very common. Which is great because if you go this demo page you can watch a video which tests whether you have got da auditory synesthesia. I’m hoping that beyond my mom and my wife and my dog who read this blog, maybe there are enough people out there to actually find one who tests positive in this test. If you do, please comment! It would be great to hear from someone for which this isn’t just a press release.