Why Does Evolution Allow Some People to Taste Words?

By KER THAN - NATIONAL GEOGRAPHIC NEWS
Added: Fri, 25 Nov 2011 22:33:48 UTC

A neural condition that tangles the senses so that people hear colors and taste words could yield important clues to understanding how the brain is organized, according to a new review study.

This sensory merger, called synesthesia, was first scientifically documented in 1812 but was widely misunderstood for much of its history, with many experts thinking the condition was a form of mild insanity.

"It's not just that the number two is blue, but two is also a male number that wears a hat and is in love with the number seven," said study co-author David Brang, of the University of California, San Diego (UCSD).

"We're not sure if these personifications are [also a symptom of] synesthesia, but we think this is what derailed a lot of scientists from being interested in it. ... They thought these people were making it all up."

Over the past 30 years, though, a growing body of evidence has shown that synesthesia has a physical basis—for example, the brains of synesthetes are wired differently, and the condition is highly heritable, which indicates there is a genetic component.

In fact, the study authors think it's possible such a strange phenomenon has survived in an evolutionary sense because it offers people certain benefits to creative thinking.

"Ninety-five to ninety-nine percent of synesthetes love their synesthesia and say it enhances their lives," Brang said.

Early misunderstandings of synesthesia were due in part because the associations that synesthetes described were very precise and detailed, prompting some experts at the time to link the condition with mental disorders such as schizophrenia.

Another early "view held that synesthesia was a 'throwback' to a more evolutionarily primitive state," said study co-author Vilayanur Ramachandran, also a neuroscientist at UCSD.

Today scientists have tools that allow them to probe the brain in ways that were impossible 200—or even 10—years ago.

MORE BY KER THAN

Gorilla Youngsters Seen Dismantling...

Ker Than - National Geographic News Comments

After a poacher's snare had killed one of their own, two young mountain gorillas worked together Tuesday to find and destroy traps in their Rwandan forest home