How the Blind Dream 盲人的梦境是什么？

How the Blind Dream 

Blindness by Yossi Kotler (2019)

Our dreams are a sort of rehash of the reality we perceive, which is why most dreams are boring renditions of what recently happened or could have happened with various tweaks. So, naturally, a blind person's dream will be experienced similarly to his reality, meaning people who are born blind relive or imagine things without imagery. Those who went blind later in life will experience sight in their dreams, but the longer they lived blind the less common visual experiences will be. 

"My boyfriend is blind since birth. He dreams in sound, smell and touch, but not taste. I asked him to lick something in his dream but he hasn't yet. He has vivid nightmares, he dreams about being made to drive a taxi but he's still blind so he just crashes again and again. He never dreams he can see, because he has never seen," according to Reddit user the battery human.

Among the few studies about blind dreams is paper published in Sleep Medicine by researchers at the Danish Centre for Sleep Medicine at Glostrup Hospital and BrainLab at the University of Copenhagen. The team recruited: 11 people who born blind, 14 who had become blind later in life and 25 normally-sighted people. Each morning, as soon as they woke up for four weeks straight, the participants had to complete a questionnaire about the content of their dreams. 

The blind participants use text-to-speech software. Some of the questions queried sensory impressions （Did you see anything? If so, was it in color? Did you taste? Smell? Feel pain?), some delved into the emotional nature of the dreams (Were you angry? Sad? Afraid?), while other questions were meant to assess the thematic content (Did you interact with someone? Did you fail at something? Was it realistic, or bizarre?). 

All non-blind participants reported a visual experience in at least on dream. However, none of the participants who were blind from birth reported any visual. Those whose blindness occurred later in life reported seeing in dreams, but the longer they had lived without sight, the fewer visuals they could experience. 

Just because they can't see in their dreams, it doesn't mean the blind's dreams are less rich in sensory information and emotions. About 18 percent of both congenital and later-onset blind participants reported tasting in dreams, compared to only 7 percent of controls. Smelling in dreams was a common occurrence for 30 percent of the blind participants, compared to 15 percent of controls. 

Also, 70 percent of the blind reported touch sensations in at least one dream, compared to 45 percent of control. Perhaps the most common dream stimulus is hearing, which 86 percent of the blind participants reported compared to 64 percent of controls. Those who were congenitally blind reported even more drastic differences: 26 percent tasted, 40 percent smelled, 67 percent touched and 93 percent heard in at least one dream. 

The blind have four times more nightmares than sighted people. One notable exception stood out- the congenitally blind experienced nightmares 25 percent of the times, compared to only 7 percent of the later-onset blind group and 6 percent of controls. The results held even after the researchers controlled for sleep quality, which is poorer among the blind. The researchers don't know for sure why this happens, but they have some hunches based on the theory of why nightmares happen in the first place. 

"The study confirms an already existing hypothesis that people's nightmares are associated with emotions they experience while awake. And blind people apparently experience more threatening or dangerous situations during the day than people with normal sight," says study lead author Amani Meaidi " According to these theories, nightmares can be seen as threat simulations, as a mentally harmless way by which the human mind can adapt to the threats of life,“ the researchers write. ” The nightmare givens an individual an opportunity to rehearse the threat perception and the avoidance of coping with the threat." 

                    But Now, I see... Chris Cook Artist 

               Blind Painting by Maizianne