There has been much debate whether or not synaesthesia has provided evolutionary value for humans. Having been on this discovery journey for a while myself, I have witnessed and experienced the benefits of synaesthesia. I believe synaesthesia provides a very powerful tool of mind categorization, and helps its bearers to understand the world better. In a way, I see synaesthesia as a result of how an individual’s intuition gets manifested.
Skye developed a new synaesthesia, i.e., People to Sound Synaesthesia, this month. It is a bit comical. He could hardly hold his own amusement when he was telling me about this.
He always thought one of the girls in his grade was half Asian. She looks very Asian, so does her mother. He started hearing a funny oriental music whenever he saw the mother waiting to collect the daughter. He finally heard the mother talking, and realised that she had a New Zealand accent. He curiously asked the girl if her mum was a New Zealander who had Asian heritage. He was told not at all.
By then, he had already developed the same oriental music response towards that girl except the tone was 2-3 octave higher, and more comical. Confused by his instinct through his synaesthetic experience, he asked me how someone looked so Asian did not have Asian heritage.
“Ah, they must be New Zealand Maori, indigenous New Zealanders. You are right, they were originated from Polynesia. That’s why some of them look very much like Asian.” I explained.
Skye has made two close friends, a girl and a boy, at school this year. Now he has synaesthetic sound responses to both of them. Skye thinks the girl is a younger female version of him. He can hear a farm music tone when he plays with the girl. But the sound he hears from the boy is very different. Skye calls the boy his hyperactive friend, and hears an air conditioner running non stop while he is playing with the boy.
Earlier this month, Skye’s school organised a camping trip. After some thinking, he told me that he would like his hyperactive friend to be his cabin mate. Skye has always been a good sleeper who needs a lot of sleep. I asked him if he was worried that he would be kept awake all night. His logic was very convincing. “Mum, because he is hyperactive during the day, the chances of him being under active at night is very high. So it’s worth the risk.”
It turned out just like what Skye had predicted that his friend fell asleep every evening by 7pm whilst every other kid was still partying.
Skye develops new synaesthesia on a regular basis, on the other hand, some of his synaesthesia are lost or weakened over the time. Looking back last 12 months, the most significant ones that he has almost lost are ticker-tape and mirror-touch synaesthesia. His theory is that those two synaesthesia types have served their purposes, and are no longer beneficial to him. Take ticker-tape as an example, it used to assist him significantly with his spelling and learning a new language. Occasionally, he used it to double check what people had said if he was not listening carefully. After six years of having it, Skye did not feel he needed it any more. Now a good speller and a more engaging individual, he uses it less and less, to a point that this synaesthesia has almost disappeared.
Scientists believe that the synaesthesia weakening is a result of a pruning process that each individual goes through. However, my view is very different. The pruning process is only one of the factors. The main reason I believe that contributes to the loss of synaesthesia is the less use of it. With the increased maturity and better developed skills, some synaesthesia types become less important to us. The less we need them, the less useful they become, the more chance they become redundant. However, those surviving synaesthesia types often provide distinct advantages to their bearers, thus the gene has survived. That’s my hypothesis.