‘From Stroboscope to Dream Machine: A History of Flicker-Induced Hallucinations’ is a wonderful article that has just appeared in medical journal European Neurology. It charts how an early finding in visual neuroscience was adopted by the Beat writer William Burroughs and became a fixture of the psychedelic sixties.
Flicker induced hallucinations have been noted throughout history and typically occur when a strong light flashes between 8 and 12hz, also known as the alpha rhythm. They most commonly trigger a type of hallucination called a form constant that comprises of geometric shapes and patterns.
Alpha rhythms have been heavily linked to the function of the occipital lobe and, as we suspect from recent research, ‘inputting’ alpha waves into the visual system via flickers seems to cause hallucinations by knocking a deep brain structure called the thalamus and the occipital lobe out of sync.
As both are part of the visual system, the effect is a bit like knocking a conversation out of sync – misperceptions occur.
Burroughs happened upon the phenomenon and set about creating a machine to produce these hallucinations:
The flicker phenomenon reminded Burroughs of a story he had recently been told by his soul mate Brion Gysin (1916-1986). At the time they both inhabited a cheap hotel in 9, rue G√Æt Le Coeur, a small alley in the middle of the Latin Quarter of Paris. The place has been known as the Beat Hotel ever since. Gysin was a man with many skills; he was a painter, a poet, a calligrapher, a musician and a cook, all in one lifetime.
On December 21, 1958, as his diary reports, he had been travelling on a bus in southern France. He had fallen asleep, leaning with his head against the window pane. On passing by a row of trees, sunlight came flickering through and Gysin started to hallucinate:
‘an overwhelming flood of intensely bright patterns in supernatural colours exploded behind my eyelids: a multi-dimensional kaleidoscope whirling out through space. The vision stopped abruptly when we left the trees. Was that a vision?’.
Gysin knew by experience what neurophysiologists like Walter were talking about. Burroughs was able to hand him the theoretical framework.
The next step was to manufacture a stroboscope for private use. Gysin persuaded one of his friends, Ian Sommerville (1940-1976), to make one. Sommerville, who was originally a mathematician, came up with a simple but effective design
This was later developed into the commercially produced dreammachine, essentially a light with a rotating slotted lampshade designed to produced flickers in the alpha range. It became popular as both a way of inducing hallucinations on its own and as an aide to hallucinogenic drug trips.
There are plans online from a company who still make the machines to order.
The hallucinations don’t occur in everyone (in fact, I’ve probably spent a few hours of my life in front of a frequency controlled strobe trying to trigger the effect with no luck) and in people with photosensitive epilepsy the flickers can trigger seizures.
The effect is almost unknown in the psychedelic circles circles in which it was once popular, but has now been adopted by neuroscientists wanting a lab-based method to research hallucinations.
If you’re interested in reading more about the whole fascinating story, I can’t recommend the short but fascinating book Chapel of Extreme Experience enough.
Link to full-text of article on flicker hallucinations.
Link to DOI entry for same.