Why you should care
For those who can’t see, dreams reflect their waking lives — meaning they hear, taste, touch and smell much more than sighted individuals.
Years ago, Tom Lane dreamed that someone was calling out to him from a van parked outside his Los Angeles home. He recognized the driver right away: his idol, Jimi Hendrix. The musician wanted to give him one of his guitars. So Walden climbed inside and started jamming on one. But it “had a strange vibe.” Although unplugged, it still wailed and buzzed with electricity.
For most people, dreams are intensely visual. Lane’s dream, though, was anything but; the 60-year-old computer instructor has been blind almost since birth. He can perceive some light — but has never seen color or shapes. He recognized Hendrix from the sound of his voice and knew the guitar was a Fender Stratocaster from its sleek, contoured shape.
Sometimes people think we can see like sighted people in our dreams …
It makes sense that most people’s dreams are primarily visual. After all, we rely on our vision and hearing far more than other senses. But according to a study published in Sleep Medicine in February, blind people’s dreams contain a much more diverse array of sensory information, including sounds and tastes — all the senses other than sight that they use to navigate their world.
Researchers from the University of Copenhagen and Glostrup Hospital in Denmark recruited 50 adults for the study: 11 blind from birth (or congenitally blind), 14 who became blind after age 1, and 25 sighted controls. Over a four-week period, whenever the participants had a dream, they completed a questionnaire about it as soon as they woke up using a computer with special text-to-speech software.
The questionnaire asked about sensory impressions (Did you see anything? If so, how clearly? Did you taste, smell or hear anything?); emotional content (Did you feel happy? Sad? Scared?); and thematic content (Did you fail at something? Did you interact with anyone? How realistic or bizarre was the dream?). The questionnaire also asked whether the dream was a nightmare.
A whopping 70% of the blind participants experienced a touch sensation, versus 45% of sighted controls.
As expected, all the sighted participants reported a visual impression in at least one dream, while none of the congenitally blind participants reported any. For those who lost their sight after age one, the longer they had lived without sight, they less they reported seeing in their dreams.
“Sometimes people think we can see like sighted people in our dreams,” said Kellie Walders, an assisted technology instructor in L.A. who has been blind since shortly after birth, but has some light perception. “But I can only see the amount that I see in real life because that’s all I know.”
Blind participants experienced other senses more intensely than sighted controls. About 86% of blind participants — both congenital and later-onset — reported hearing in at least one dream, compared to 64% of controls. About 18% of the blind participants tasted, compared to only 7% of controls. Twenty-eight percent of the blind participants smelled in at least one dream, compared to 15% of controls. And a whopping 70% of the blind participants experienced a touch sensation, versus 45% of controls. The differences are even starker when looking only at the congenitally blind group; 93% heard, 26% tasted, 40% smelled and 67% touched in at least one dream.
The blind participants, however, had far more nightmares.
Lane once dreamed about walking into a woodshop, which he recognized from its sharp turpentine odor. Walders often dreams about making coffee, which she can both smell and taste.
The emotional and thematic content wasn’t all that different between blind and sighted participants, who reported roughly the same numbers of successes, failures and social interactions. They also experienced the same frequency and intensity of each emotion, and almost equal levels of bizarreness.
The blind participants, however, had far more nightmares. About 25% of congenitally blind participants reported that at least one of their dreams was a nightmare, versus 7% of the later-onset blind group and 6% of sighted controls. The researchers aren’t exactly sure why but suspect that an explanation might lie in one theory that nightmares serve as “threat simulations … an opportunity to rehearse the threat perception and the avoidance of coping with the threat,” they wrote.
Sure enough, the congenitally blind participants’ nightmares often reflected threats they face in their waking lives, like being run over by a car, getting lost or falling into holes at construction sites. Walders once dreamed about losing her guide dog. “I felt panicked and kept calling and calling her,” she recalled. “She’s like my baby.”
For both blind and sighted individuals, their dreams tend relate to experiences in their waking lives, including desires, fears and daily routines, the researchers wrote. Even in our sleep, we’re not so different after all.