When the brain stops receiving normal information, it often starts manufacturing information of its own. That is one of the common mechanisms behind hallucinations such as hearing voices, seeing things, and phantom limbs.
Reduced sensory input to the cerebral cortex is an important feature of schizophrenia. Many people with schizophrenia see things others cannot see and hear voices commanding them to do all kinds of things. The mechanism behind these hallucinations may simply be that the cerebral cortex is receiving less information.
After an amputation, some people develop a phantom limb sensation: they can still feel the part of the body that no longer exists. This may also happen because, deprived of normal information from the limb, the brain “creates” the sensation that the lost arm or leg is still there.
Some older people with cataracts or other visual impairments develop Charles Bonnet syndrome. When their surroundings grow dim, they may suddenly see vividly colorful scenes. This too may be because a lack of visual information causes the brain to switch into “creative mode.”
When a climber is alone, scaling a desolate cliff, intense hallucinations sometimes appear: they may feel that another person has appeared beside them, or have an out-of-body experience and see themselves climbing. This may likewise be because, alone high in a barren mountain landscape, the brain is short of normal input.
In We Are Our Brains, neuroscientist Dick Swaab speculates that these “mountain-climbing hallucinations” may explain why so many saints in religious traditions spent time living alone in the mountains before “receiving divine revelation”:
Moses received the Ten Commandments from God twice on Mount Sinai. The second time, according to the Bible, Moses “stayed alone in the mountain for 40 days and 40 nights, without a drop of water or a bite of food.”
Muhammad also saw the archangel Gabriel while thinking alone on Mount Hira.
“They all experienced light, sound, and fear, consistent with what climbers describe. In extreme isolation, the brain produces thoughts it has already stored, and the results of those thoughts can become a new religious doctrine.”
In fantasy novels, the Taoist cultivators seeking immortality always hide away in lush, scenic forests to practice. But it seems that this environment may not actually be conducive to attaining enlightenment. What would suit them better, surely, are deserts and wastelands where not a blade of grass grows.
Notes
- These short popular-psychology essays were written at the time to accompany the content of the “New Psychology Lessons” series, Zhichao Wei: New Psychology Lessons, and were published on the now-closed platform “F Tuan.” The original link no longer exists.
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