A new study found people can be trained to "see" letters of the alphabet as colors in a way that mimics those with naturally-occurring synesthesia, and the conclusions had interesting implications for IQ levels.

Synesthesia is a neurological condition in which those who have it experience an "overlap" in senses that manifest themselves in ways such as being able to "see" letters or "taste" words, the University of Sussex reported.  

Researchers have been puzzled over whether or not this condition is genetic or is triggered through environmental factors, for example by colored letter toys played with as a child. While both of these could be true in different cases, researchers decided to test out the theories.

To make their findings the scientists had a group of adults participate in a nine-week-long training program to see if they could cause the participants to develop the "key hallmarks" of the condition. Out of the sample, 14 people were able to develop significant letter-color associations and pass the standard test for synesthesia.

In a surprising turn of events, the researchers found those who developed symptoms of synesthesia saw an increase in IQ of about 12 points when compared with a control group that did not receive the sensory training.

"The cognitive boost, although provisional, may eventually lead to clinical cognitive training tools to support mental function in vulnerable groups, such as Attention Deficit Hyperactivity (ADHD) children, or adults starting to suffer from dementia," said Daniel Bor, who co-led the study.

 "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. But it does show that synesthesia is likely to have a major developmental component, starting for many people in childhood," study co-leader Nicolas Rothen concluded.

The findings were published Nov. 18 in the journal Scientific Reports.