[If you cannot see the flash video below, you can click here for a high quality mp4 video.]
Interviewee: Melissa Saenz, Caltech; Johannes Pulst-Korenberg
The Sound of Silence
Caltech neurobiologist Melissa Saenz will never forget the chance encounter that led to a neuroscience discovery. She invited a group of students who were passing by on a campus tour to see her lab. It just so happened that she had a silent video running on her monitor that looked sort of like stars moving in and out.
Saenz recalls, “Out of the blue one of those students asked, ‘Does anybody else hear something?’ And it was indeed a silent display, and he was the only one that had that perception.”
The student was economics graduate student Johannes Pulst-Korenberg. He remembers the reaction in the room.
“Everyone looked at me like I was crazy,” he says, adding that Saenz was the exception.
Saenz realized that Pulst-Korenberg might have a benign condition called synesthesia, a “cross-wiring” of the senses. She knew of many different kinds of synesthetes, as they are called. Some see bursts of color when they hear music; others associate words with particular tastes. Saenz did some research and found that there were no previous reports of people who “hear” motion or flashes of light.
“After my discussion with Johannes I was very curious as to whether I could find more people with the same experience. I didn’t know if Johannes would be one in a million or if I would be able to find others, but now I had a question to ask,” explains Saenz.
Do you hear anything when viewing the moving dots? Play the movie repeatedly for best effect. Courtesy Melissa Saenz.
Saenz showed her silent video to hundreds of people on the Caltech campus and asked them if they heard sounds. She found three more people who said they did. When she interviewed them she learned that they each had different sound perceptions in response to seeing certain things. They reported hearing beeping, whirring and tapping.
What they all had in common was that their individual sound perceptions were consistent for a given sight. For example, when Pulst Korenberg sees the jerky motion of ants as they touch each other and change
direction, he always hears one type of sound, but flashing lights elicit a different sound.
Saenz decided to test the synesthetes.
“The goal of the study was to devise a test that would provide objective evidence that the people with synesthesia really were hearing the sounds they claim to hear,” explains Saenz. “So my goal was to devise a task for which people with this synesthesia would have an advantage, if there sound perceptions were real.”
Saenz tested them with patterns similar to Morse code—an auditory kind with beeps, and a visual one with flashes. She explains that picking up a series of beeps by ear is easier for most people than processing a series of flashes. She predicted that if she tested the synesthetes and regular people, the synesthetes would do better on the flash test. Saenz tested Pulst-Korenberg and the other three synesthetes and a group of people without synesthesia.
Also on ScienCentral
She asked both groups to listen to pairs of beep patterns and pairs of visual flash patterns. They were then asked whether the patterns were the same or different. Both groups did well on the beep recognition, scoring about 85-percent correct. On differentiating between the flash patterns, the regular people’s performance dropped to 55-percent correct, or just above chance. But the synesthetes scored 75-percent correct, because as Saenz explains, “They not only saw the visual flashes, but they also heard them.”
It’s enough to make you wonder if this experimental advantage translates to real world advantages. For instance, might synesthetes like Pulst-Korenberg have an advantage in sports like baseball or tennis? Would an audio sountrack of an approaching ball make them better at hitting it? Saenz isn’t willing to speculate on that just yet, but she jokes that they would probably do very well as “visual Morse code operators.”
Pulst-Korenberg points out that before he met Saenz, he rarely discussed his perceptions with others because he got incredulous reactions. He says now he feels vindicated and relieved to know that Saenz has proven his personal soundtrack is real.
But does he wish it would go away? While things like silent Internet popup ads can make annoying and distracting sounds, he thinks the good outweighs the bad. He says life’s just more interesting when you can hear things like the flap of a butterfly’s wings or the sun’s shimmer on water.
“I think it’s a ton of fun to have all this,” Pulst-Korenberg says. “I mean, it makes my life certainly less boring.”
Elsewhere on the Web
Share on Facebook |
Tweet This |