Here is an interesting factoid — Do the blind dream differently that sighted people? Well, the answer depends on a couple factors.
If someone was blind before 5-7 years of age, their capability to dream visual images will fade over time. And if that person was born blind, or went blind as an infant, they will not have dreams like someone who has their sight. No visual imagery or colors to speak of at all.
Their dreams will consist of only auditory and other sensory related sensations (touch, smells). Although, these sensations will be greatly magnified in someone who is blind, when compared to someone who is not. They’re often reported as ‘intense’.
For someone that has lost their sight later in life, they will still dream as though they can see, colors included. But for people they know, often the blind report that their faces are now just blurs or how they imagine they look.
Helen Keller reported in her autobiography, that her dreams were devoid of any kind of sight, sound or thought. That they only contained strong abstract sensations and intense fear.
Helen Keller’s Dreams
She wrote, “My dreams have strangely changed during the past twelve years. Before and after my teacher first came to me, they were devoid of sound, of thought or emotion of any kind, except fear, and only came in the form of sensations. I would often dream that I ran into a still, dark room, and that, while I stood there, I felt something fall heavily without any noise, causing the floor to shake up and down violently; and each time I woke up with a jump. As I learned more and more about the objects around me, this strange dream ceased to haunt me; but I was in a high state of excitement and received impressions very easily. It is not strange then that I dreamed at the time of a wolf, which seemed to rush towards me and put his cruel teeth deep into my body! I could not speak (the fact was, I could only spell with my fingers), and I tried to scream; but no sound escaped from my lips. It is very likely that I had heard the story of Red Riding Hood, and was deeply impressed by it. This dream, however, passed away in time, and I began to dream of objects outside myself.”
Deaf people experience something similar, but opposite of blind people. Those who were born deaf don’t hear anything in their dreams. People talking in to them in their dreams use sign language. The visual imagery are amplified in their dreams and incredibly vivid.
Bonus factoid: Rapid eye movement during sleep occurs very mildly or not at all in people blinded as children.
Do blind people dream?
Hurovitz, C., Dunn, S., Domhoff, G. W., & Fiss, H. (1999). The dreams of blind men and women: A replication and extension of previous findings. Dreaming, 9, 183-193.