In A Nutshell
Similar to synesthetes who experience a blending of their senses, people without synesthesia can be taught to “see” letters of the alphabet as specific colors. Most of the study participants also developed emotional reactions to the letters, such as experiencing a letter as boring or calm. On average, each of the people who participated in this training had an increase in his or her IQ of 12 points.
The Whole Bushel
Believed to affect about 1 in every 23 people, synesthesia is a rare neurological condition in which a person experiences an overlap or linkage of different senses. Most commonly, people with synesthesia (“synesthetes”) see letters and numbers as certain colors (“grapheme-color synesthesia”). Others “taste” words or see colors when they hear sounds. There are many variations of this fascinating condition.
Grapheme-color synesthesia has two main forms. In the first one, the synesthete reads a number or letter and sees the corresponding color in his mind’s eye instead of on the page. With the second form, the synesthete sees a colored number or letter directly on the page.
The exact cause of synesthesia is still a mystery. Two popular theories start with the same assumption: that human babies are born with neural connections between the regions of their brain that are associated with senses.
The first theory is that these neural connections are normally pruned early in life as a child’s brain develops, but synesthetes are able to keep some of these connections.
The second theory is that these neural connections atrophy over time but may still be accessed in certain ways. One of those ways may be hypnosis, where researchers found that they could influence four hypnotized people to see numbers in color. When no longer hypnotized, these people lost their synesthetic abilities. That gives a boost to the atrophy theory because new neural connections couldn’t have been developed and lost again so quickly.
But it’s also possible that genetics or environmental factors, like playing with toys that have colored letters when we’re young, may cause synesthesia to emerge. We just don’t know yet.
Nevertheless, there are researchers from the University of Sussex who are studying whether synesthesia can be learned. At their Sackler Center for Consciousness Science, they created a training program to determine if adults without synesthesia could learn to see letters in color in just nine weeks.
These researchers had previously uncovered evidence that there’s a learning component associated with synesthesia, somewhat similar to the way we have to learn to read. No matter what type of synesthesia someone has, there has to be a stimulus, or “inducer,” to trigger the experience. The synesthete has to understand the meaning of that stimulus, whether it’s a musical sound or a letter or a number. In other words, he has to understand that the letter “A” is an “A” to consistently see it in the same color. Sometimes, the associations were learned in a previous experience. For example, the synesthete may have seen refrigerator magnets that were colored letters in his youth and then began to see letters with those specific colors as he learned to read.
When training someone to see letters in color, it’s imperative that the person automatically sees the same colors for specific letters over time, especially after the training ends. The longer the training period, the more likely it will be a success. An earlier program at the University of Amsterdam tried to train people to see letters in color by having them read texts with colored letters. The more exposure the person had to reading colored texts, the higher the association between letters and specific colors. It’s like using a mnemonic device to help your memory. But with ordinary people, the letter-color associations were gone several months after the training.
In the latest study, the Sussex researchers trained 14 participants to complete demanding tasks that could be solved only by using particular associations of colors with letters. The group did develop strong connections between letters and specific colors. Most also developed emotional reactions to the letters, such as experiencing a letter as boring or calm. On average, each participant had an unexpected increase in his or her IQ of 12 points.
The researchers concluded that we can use perceptual training to experience the world in completely new ways. They hope to develop training tools to help mental functioning in vulnerable groups like dementia patients or children with attention-deficit/hyperactivity disorder.
“It should be emphasized that we are not claiming to have trained non-synesthetes to become genuine synesthetes. When we retested our participants three months after training, they had largely lost the experience of ‘seeing’ colors when thinking about the letters,” said researcher Nicolas Rothen. “But it does show that synesthesia is likely to have a major developmental component, starting for many people in childhood.”
Show Me The Proof
University of Sussex: Training can lead to synaesthetic experiences, study shows
LiveScience: People ‘See’ Common Letters in Brighter Colors
Wired: Hypnosis Lets Regular People See Numbers as Colors
The Conversation: Can you learn to taste and smell the letter B?
PLOS ONE: Pseudo-Synesthesia through Reading Books with Colored Letters