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By Roger Highfield on

Dreamachine: Throwing Open the Doors of Perception

At the next Science Museum Lates, visitors will learn about the Dreamachine. Roger Highfield, Science Director, discusses this cerebral adventure with neuroscientist and bestselling author Anil Seth.

If you have ever wondered what it feels like to fall through a wormhole (I certainly have), then closing your eyes as you submit to the pounding sounds and flashing lights of Dreamachine is one way to give you a vivid taste.

Using nothing more than white lights, Dreamachine can conjure up a rainbow of colour, as I discovered when it tried it out.

And even though my eyes were clamped firmly shut, I could see a twisting funnel like the maw of a wormhole that gradually melted away to shifting mosaics of red, then kaleidoscopic patterns of blue honeycomb.

Dreamachine photographed at London’s Woolwich Market. Credit: Urszula Soltys

One of 10 national projects in Unboxed UK, a celebration of UK creativity, Dreamachine is the closest you can get to an out-of-body experience without having to resort to hallucinogens or virtual reality.

All it uses is deep breathing, strobe lights and a rhythmic soundtrack. More than 25,000 people have already taken part, with thousands more still to experience it.

You can find out more about what Dreamachine reveals about how our brains construct reality later this month at Lates when I discuss the project with neuroscientist and bestselling author Anil Seth of the University of Sussex, Director Jennifer Crook, and Jane Hall of the Turner Prize-winning collective Assemble that designed Dreamachine.

Flash of Inspiration

The origin of the Dreamachine dates back to research carried out seven decades ago by the neuroscientist Grey Walter, though the ideas that underpin it are even older.

One way that Grey Walter had tried to understand how the brain functions was by building ‘artificial animals’. In the Modern World gallery of the Science Museum you can see one, a cybernetic tortoise that he developed to show how complex behaviours arise from simple rules (the  tortoise even amused the father of AI, Alan Turing, during the Festival of Britain in 1951).

This bottom-up approach complemented his studies of the brain, notably his research on EEG, which picks up its electrical activity and Grey Walter was interested in how it changes in response to stroboscopic flashes.

But he also noted that these flashes caused hallucinations and, alluding to the cause, had written: “In a telephone system the meaning of a message received depends on the sender; in a sensory system the meaning depends on the receiver.”

He was well aware of the brain’s creative ability from Charles Bonnet syndrome, bizarre hallucinations such as distorted faces, costumed figures and ghostly apparitions that are ‘seen’ by people who are losing their sight. We now think that spontaneous activity in the visual centers of the brain trigger these visual hallucinations.

The link between flickering lights and hallucinations was also well known by then. As one example, an 1819 account by the Czech anatomist Jan Purkinje describes how the effect occurred when waving his hand between his eyes and a gaslight.

This idea that our experience comes as much from the brain as our surroundings chimes with the thinking of German scientist Hermann von Helmholtz who in the 19th century suggested that perception – figuring out what’s out there around us  – involves the brain blending ambiguous sensory signals with its best “informed guesswork” about the world.

Thanks to Grey Walter, these flashy hallucinations would also beguile the Beat Generation in the 1960s, who started manufacturing their own stroboscopes to trigger the hallucinatory effect.

Most famously, Artist-inventor Brion Gysin and William S. Burroughs’ “systems adviser” Ian Sommerville built a pioneering version in 1959, consisting of a light in a cylinder with slits cut in the sides, which rotated on a record turntable at 78 or 45 revolutions per minute.

They billed what they dubbed the dreamachine as the ‘first artwork to be experienced with your eyes closed.”

Dreamachine participants lying down with their eyes closed. Credit: Brenna Duncan

How the Dreamachine Works

Even though the brain is receiving only degraded information – flashing white light perceived through firmly shut eyes – the flickers influence our brain rhythms, in particular the ‘alpha’ rhythm which consists of slow brain waves. This rhythm is present when we are relaxed but awake, and is also prominent in parts of the brain that process visual signals.

The patterns might also relate to the way the visual cortex is wired and how its underlying circuits are organised. ‘Either way, the Dreamachine reveals the extraordinary power of our brains and minds to create our conscious world,” says Anil Seth.

‘My hypothesis – which I should stress is unverified – is that it is not only that the input is degraded, but that it is both extremely degraded and the brain is not expecting any visual input at all, since the eyes are closed. This prior state, neurophysiologically, also corresponds to increased alpha – a brain state ripe for entrainment by the strobe.  Thus, we have a combination of two factors, strong brain activation by a stimulus in a state where the brain is not expecting to be activated.

‘The second part of the story is relating the content of the hallucinations to the intrinsic structure of visual cortex – which serves as an ‘input’ given the undifferentiated nature of the stimulation,’ he adds. ‘There is a rich body of prior neuroscientific work to draw on here, including the pioneering contributions of Jack Cowan who built rich mathematical models of the nature of geometric visual hallucination.’

The Dreamachine’s flickering lightshow is accompanied by a specially-composed soundtrack and there are many examples of how one of our senses can affect others, for instance a single flash accompanied by two beeps results in the perception of two flashes. This mingling of the senses is most vivid in synaesthesia – when a person can hear silent flashes, taste colours and so on.

Visitors creating artworks based upon their Dreamachine experience. Credit: Urszula Soltys


Dreamachine provides convincing evidence that the brain can fashion experiences that do not directly reflect the way the world is. I knew there were no spatial patterns or colours pulsing around me in the Dreamachine that I tried out when the experience was in Woolwich. And yet, from flashing white lights alone, my brain was generating explosions of colour and checkerboard effects.

The Philosophy of Dreamachine

The Dreamachine experience poses a deeper question: what are we aware of in perception and hallucination? University of Glasgow philosopher Fiona Macpherson says, “one view is that in perception the brain is using its ‘best guesses’ to enable it to be directly open to the world.

‘Another is that we are never directly aware of the world around us and are only aware of things that our minds create. But if that is right, does that mean that there is a distinctive non-physical mental realm? When we hallucinate a yellow triangle there isn’t one in the world in front of us that we are aware of and there certainly aren’t yellow triangles inside the brain.”

Anil Seth and Fiona Macpherson agree that this is a hot topic in both science and philosophy.

Because our brains play an active role in interpreting sensory data, our perceptual worlds may well be unique. One goal of the Dreamachine project is to deepen our knowledge of ‘perceptual diversity’, both by looking at how peoples’ experiences within Dreamachine vary, and through a citizen science project called the Perception Census.

“Because it seems as though our perceptual experiences reveal the world to us just as it is, it’s difficult to take on board the possibility that each of us may experience things in a unique way,” says Anil Seth. “But we very likely do. The Perception Census is the first attempt to measure this previously hidden ‘perceptual diversity’ across many aspects of perception.

The online survey consists of a set of short, simple, fun, and engaging interactive illusions and surveys. Taking part not only helps the research, it also gives people the chance to learn about their own powers of perception. If enough people participate, we could rewrite our understanding of how we each experience the world – and perhaps even provide new platforms for building connection and empathy.”

Everyone is encouraged to take part in the Perception Census, whether they’ve been to the Dreamachine or not, he said, adding that the first results are expected by the end of this year.

Dreamachine is currently operating at Carlisle Memorial Church, Belfast (25 July – 4 September 2022) and Murrayfield Ice Rink, Edinburgh (13 August – 25 September 2022).