Synesthesia: The Science Behind Seeing Sounds & Tasting Color


Synesthesia is a rare and incredible condition
where people see sounds, hear colors… But what happens in someone’s brain that makes
them this kind of super-human? Synesthesia is a neurological condition where
a person’s stimuli are crossed. When a synesthete experiences stimuli along one cognitive pathway,
another pathway activates as well, causing an involuntary sensory experience. Five percent
of humans have some form of synesthesia, and they can come in different types. For example,
violinist Kaitlyn Hova hears music and sees corresponding colors; but a local painter
and artist Mary Syring feels that certain letters, numbers or days of the week have
specific color shades. If you want to see a VR experience with Kaitlyn, to experience
her synesthesia, we just posted one here on DNews! It’s super cool. To be diagnosed with synesthesia, according
to Dr. Veronica Gross of Boston University, the synesthetic reaction has to be quote “involuntary
but elicited,” “irrepressible,” and “stable.” There are a bunch of different types of synesthesia.
The most common are color-graphemic, where letters or numbers seem to have colors or
patterns — like Mary, or color-auditory where sounds produce “colors, textures and shapes,”
— like Kaitlyn. But theoretically, there could be as many types of synesthesia as there
are sensory pairings! We could experience taste-hearing pairings (where tasting things
produces a perceived sound), or sound-touch (touching different things produces sounds),
smell-color, or a handful of other combinations — depending how many senses you believe we
have, there could be dozens of synesthetes. On my other show TestTubePlus, I discussed
how human senses include thermoreception, pressure, pain, magnetoreception, balance,
and more and more… Studies across a bunch of journals have attempted
to figure out just what’s going on the brains of synesthetes. Researchers conducted fMRI
scans of synesthetes while activating their specific synesthetic triggers
and evidence to support the theory that their brains are somehow cross-wired. In one example,
color-auditory synesthetes saw their superior frontal gyrus light up, which is connected
to self-awareness and the sensory system, as did what’s called the COLOR CENTER, or
V4 and V8 and it’s neighboring region, the fusiform gyrus (they’re not sure what that
bit does). Synesthete was seeing colors, but curiously, the primary visual cortex wasn’t
active, indicating the color cortex was wired to directly interact with the fusiform gyrus
and somehow… create the experience. Though scientists don’t know much about synesthesia,
people who have it say they’ve experienced this extrasensory cross-talk for as long as
they can remember. Researchers have yet to understand just how people develop it, but
they have identified two types, developmental — or inborn, and acquired. Developmental
seems to be genetically, passed on through families, and some theorized synesthesia might
be an inherited trait on the X chromosome, as its skews heavily female; but a study in
the American Journal of Human Genetics disproved that; finding instead multiple chromosomes
are implicated in the transmission of the condition. Acquired synesthesia, on the other
hand, can manifest in those who are on hallucinogenic drugs, or, in people who’ve had neurological
conditions like epileptic seizures which may have altered their physical brain matter. According to Scientific American, grapheme-synesthetes
report having good memory for phone numbers, security codes, and polysyllabic anatomical
terminology, because the colors aid them in recalling the information. A paper in PLOS
One from March 2015, attempted to explain letter-color combination synesthesia by looking
at the magnetic english alphabet some people have on their fridge. Of the 6500 synesthetes
tested, they found at least 6 percent of the participants saw shades that matched those
from the magnetic toy! In fact, those born closer to the date it was released saw even
more alignment with the colors: up to 15 percent! Some scientists think, perhaps children learned
to associate colors with words or letters inadvertently, to aid their memory through
synesthetic adaptation! Of course, this doesn’t explain all synesthetes,
only a small number, but shows some could learn the behavior. Most of the research I
found was in English, I’d LOVE to see more in other languages, especially ideogram-based
characters like Chinese! In the end, synesthesia is not a disorder,
and the cause remains unknown. It’s an incredible mystery of the human body. Not all auditory-visual
synesthetes see the same thing, and not all grapheme-synesthetes connect the same words,
letters or numbers with the same colors; even within the same family, two synesthetes will
manifest these differently. As of now, scientists are scanning and learning as much as they
can about the condition to learn about how our brains perceive the world and construct
our individual realities. I’ve been wanting to talk about synesthesia
for a long time, and here on DNews, TODAY, you might have seen we just posted a brand
new Virtual Reality experience. You can watch Kaitlyn play the violin and see her synesthesia
along with her music. It’s really incredible. On the computer you can click and drag the
video around to see what Kaitlyn sees, but it even better on a phone, because the accelerometer
will follow your head as you look all around the scene. EVEN BETTER if you use headphones
and grab a VR headset or one of these cardboard VR kits online… Then you can see what it’s
like to be
a synesthete for yourself!