Can flashing light alter your mind? The science of stroboscopic stimulation
Light therapy sounds wholesome. Clean. Almost pastoral. Sit in front of a lamp. Feel better.
In our latest episode of the Strange Health podcast, we discovered that it can also mean strapping on a flashing mask and watching your own brain generate kaleidoscopic hallucinations behind closed eyelids.
The spark for this episode was a stroboscopic light device called the Lumenate Nova, promoted on social media by celebrities including Jennifer Aniston and Rosamund Pike, who serves as the brand’s creative director and is also an investor. The device claims to use carefully timed pulses of light to guide users into altered, meditative states, described by the company as “sober tripping”.
I was sceptical but gave it a go. “Sober tripping” sounded like a level of experimentation I could live with.
After watching what looked like brightly coloured fireworks, I eventually felt as if I were surrounded by a mountainscape, basking in a warm ray of sunshine coming from the left side of my vision. I had to remind myself I was on my sofa in Doncaster at 7pm. There was no sun.
The visions quietened my usually chatterbox brain. For 15 minutes, that alone felt like relief.
So what is actually happening? Stroboscopic light delivers rhythmic pulses that pass through the eyelids and stimulate the retina. When those flashes align with rhythms the visual system naturally oscillates at, including alpha-range activity, signals in the visual cortex begin to synchronise with the pattern. The result can be surprisingly vivid: spirals, tunnels, lattices, shifting colours and, for some people, more complex scenes with recognisable shapes and places.
The brain is constantly predicting what it expects to see. It breaks visual input into edges, colour and movement, then rebuilds it into the seamless scene we experience. When rhythmic light disrupts those patterns, the brain tries to make sense of the signals. Sometimes that means geometry. Sometimes it feels like landscapes.
We spoke to David Schwartzman, a research fellow at the Sussex Centre for Consciousness Science at the University of Sussex, who has been studying these effects for more than a decade. He describes stroboscopic hallucinations as a controllable way to explore how the brain constructs visual experience. They offer a glimpse of the underlying machinery of perception rather than a treatment in themselves.
Interest in stroboscopic light is not new. In 1819, the Czech anatomist Jan Purkyně described geometric patterns seen when moving his fingers in front of a candle with eyes closed. In the 1960s, artists Brion Gysin and Ian Sommerville built the “Dreamachine”, a spinning cylinder designed to induce altered states without drugs.
More recently, a large public installation called Dreamachine toured the UK in 2022, allowing tens of thousands of people to lie inside a purpose-built structure and experience synchronised light and sound. Participants reported everything from gentle patterning to overwhelming geometric worlds.
But what about the health claims? The phrase “light therapy” now covers very different technologies. Some regulate sleep and mood. Others aim to alter perception itself. Bright light therapy is well established for seasonal affective disorder (SAD). Used correctly, typically in the morning at prescribed intensities, it can help regulate circadian rhythms and improve mood in some people. That is different from stroboscopic stimulation, which targets visual perception rather than sleep-wake cycles.
Read more: How light can shift your mood and mental health
Research into strobe-based interventions for depression is ongoing. Early studies are exploring safety, tolerability and whether the immersive experience might influence mood in ways researchers are beginning to compare with psychedelic-assisted therapy. It is promising, but not yet a standard treatment.
There are also experimental trials using 40 hertz flickering light in Alzheimer’s disease, based on the idea that synchronising brain rhythms could influence disease processes. This approach remains in clinical testing and is not an established therapy.
There are risks. Flashing lights can trigger seizures in people with photosensitive epilepsy, although only a small proportion of people with epilepsy are photosensitive. Even in people without epilepsy, intense exposure can cause discomfort, headaches or nausea. Dose, brightness and individual sensitivity matter. People with epilepsy or migraine disorders may be advised to avoid stroboscopic devices.
Light can be therapeutic. It can also overwhelm. From SAD lamps to UV treatment for psoriasis and neonatal jaundice, light is powerful biology, but it is not automatically benign.
Strange Health is hosted by Katie Edwards and Dan Baumgardt. The executive producer is Gemma Ware, with video and sound editing for this episode by Anouk Millet. Artwork by Alice Mason.
Listen to Strange Health via any of the apps listed above, download it directly via our RSS feed or find out how else to listen here. A transcript is available via the Apple Podcasts or Spotify apps.
David Schwartzman receives funding from the Medical Research Council (UKRI083) and was partly supported by a grant from the UK Government for his participation in the Dreamachine Programme, as part of Unboxed2022. Katie Edwards received a Lumenate Nova device as a PR sample for editorial use in this episode.
Dan Baumgardt does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.