Unlike a lot of abnormalities, synesthesia is one that people with the condition hardly ever say they “suffer” from. In fact, most synesthetes can’t imagine living in a one-dimensional sensory world, where colors are colors and nothing else, and where the number 28 doesn’t taste like licorice and trees don’t sound like rain.

Scientists may be getting closer to bridging the two worlds, however. A new study from the University of Sussex found non-synesthetic adults who completed several weeks of intensive “synesthesia training” were able to read black text as if it were multicolored. Researchers behind the project say the results could offer some insight into the plastic nature of the brain.

Can Adults Un-Learn Black?

Most synesthesia studies rely on a phenomenon in color psychology known as the “Stroop effect.” It presents the test taker with a list of colors — Yellow, Green, Blue — each written in a typeface of a different color than what the word says. The word yellow may be written in red ink, for instance, and the word blue may actually appear yellow. The person taking the test has to say the color of the text, not read the word. Most of the time, it’s difficult. But for synesthetes, the task isn’t as hard because colors and words already have concrete associations in their brains. They have an easier time “hooking” onto the desired color.

Hoping to mimic these effects, a team led by neuroscientist Daniel Bor recruited 14 people to undergo extensive training in the lab. For weeks, the participants read from specially designed colored e-books and spent half-hour chunks of time learning 13 letter-color associations. The goal was to engrain these cross-dimensional concepts as one codified unit, much like actual synesthetes taste words and see sound. By the five-week mark, many of the participants had begun seeing colored letters instead of black text in their lab tests.

Some even reported seeing colored letters in their daily lives, Bor told NewScientist. And like actual synesthetes, the experience wasn’t frustrating, but enriching. “They were excited to have these extra experiences,” he said.

At the end of the nine weeks, most of the subjects said they’d had synesthetic moments. Ordinary road signs, for example, seemed to burst with color. “The color immediately pops into my head,” said one subject, who felt particularly strong effects. “When I look at a sign the whole word appears according to the training colors.”

Unfortunately, the effects were only temporary. When people stopped the training, their synesthetic phenomena wore off. Black was black again.

A Theory Of Development

Even if black will always be black for non-synesthetes, the field of research isn’t so cut and dry for people like Bor. The brief time people spent molding the color-sensing parts of their brains offers scientists a glimpse into how our brains develop. One theory suggests kids with synesthesia actually come into their condition armed with only a genetic predisposition toward it; any actual phenomenology (the experience of sensing) emerges as kids start learning — “hooking” colors onto letters of the alphabet, for example.

How many people, exactly, this type of research could benefit isn’t clear. The best estimates still paint a huge window for synesthesia occurrence: between one in every 5,000 people and one in every 100,000. One difficulty is that children rarely know they’re different until they are much older. Even if they do, they may hide it to avoid the embarrassment of being different. Luckily, as with any condition, as it gains prominence, stigmas tend to subside.

Up next for Bor is testing whether other languages yield a stronger effect. He wants to run the same experiment, but with Hebrew letters and people who can’t read Hebrew. Maybe the raw experience of learning to associate color to a foreign letter will make the effect last longer, he suspects.

A word in any other language would smell as sweet?

Source: Bor D, Rothen N, Schwartzman D, Clayton S, Seth A. Adults Can Be Trained to Acquire Synesthetic Experiences. Scientific Reports. 2014.