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IFLScience Meets: Anil Seth, Renowned Neuroscientist And Consciousness Researcher

We caught up with Professor Seth to learn more about The Perception Census – a large-scale online study of perceptual diversity.

Johannes Van Zijl

Johannes Van Zijl

Johannes has a MSci in Neuroscience from King’s College London and serves as the Managing Director at IFLScience.

Managing Director

Anil Seth sitting in front of a strobe light.

Image Courtesy of Anil Seth 

Anil Seth is a neuroscientist, author, and public speaker who has been conducting research into the brain basis of consciousness for more than 20 years. He is a Professor of Cognitive and Computational Neuroscience at the University of Sussex and Founding Co-Director of the Sussex Centre for Consciousness Science. He is also Co-Director of the Canadian Institute for Advanced Research Program on Brain, Mind and Consciousness, Editor-in-Chief of the journal Neuroscience of Consciousness (Oxford University Press), and a European Research Council Advanced Investigator. 

A former Wellcome Trust Engagement Fellow, his two TED talks have been viewed more than 14 million times; he has appeared in several films, and he has written for Aeon, The Guardian, Granta, New Scientist, and Scientific American. His recent book Being You: A New Science of Consciousness was an instant Sunday Times Bestseller and a 2021 Book of the Year for The Economist, The New Statesman, and Bloomberg Business, as well as a 2021 Science Book of the Year for The Guardian and The Financial Times. 


Most recently, Anil has been the lead scientist on the Dreamachine project, an innovative art-science experience using fast flickering light to induce vivid visual experiences in thousands of people throughout the UK. As part of the Dreamachine project, he has led the development of The Perception Census – a large-scale online study of perceptual diversity, shedding new light on how we each experience the world in an individual, unique way. We caught up with Anil to learn more. 

What is The Perception Census?   

The Perception Census is a new, first-of-its-kind study into what my colleagues and I have come to call ‘perceptual diversity’. It is motivated by the idea that just as we all differ on the outside, we all differ on the inside too. What do I mean by this? Research going back decades, including work by my team at the University of Sussex, has shown that we don’t just passively perceive the world ‘as it is’; instead, our brains are always actively interpreting sensory information to create our experiences. And because we all have different brains, we will have different experiences – even for the same shared reality. 

Understanding more about this inner ‘perceptual diversity’ is what The Perception Census is all about. The ways we differ on the outside are easy to see, but our inner differences are much harder to measure. Our conscious experiences are private – only I really know what it’s like to be me. And because it seems as though we see things just as they are, it can be hard even to entertain the possibility that others might experience things differently. 

The aim of the Census is to map out, for the first time, the many ways our experienced worlds are different, as well as the ways they remain similar. What’s unique about The Perception Census is that it looks into many different aspects of perception, such as vision, hearing, and time, and how they affect each other. I don’t think that any other scientific study has tried to paint such a comprehensive picture of how diverse and distinctive our ‘inner universes’ really are. 


To make this project successful we need as many people as possible to take part. Every person really does make a difference, every participant will also learn about their own powers of perception, and how they relate to others. 

How did you come to be involved with it?  

The Perception Census came about as part of a program called Dreamachine, which is one of ten commissions in the UK-wide festival of creativity, UNBOXED. I became involved as the lead scientist on the project, thanks in part to my long-standing interest in understanding the biological basis of consciousness and self, as I write about in my recent book Being You: A New Science of Consciousness. The more specific reason was because of my previous work, with my colleague and friend David Schwartzman, on something called ‘stroboscopically induced visual hallucination’.

The Dreamachine itself is a unique, collective, immersive experience which uses stroboscopic white light and spatial sound to create vivid experiences of colors, shapes, and movement – and often much more – in the minds of participants, all of whom have their eyes closed. Unlike our everyday experiences of the world around us, the visual hallucinations that arise in the Dreamachine seem to come from within, and everyone has a unique experience even though they are each exposed to exactly the same sequence of flickering white light. The history of research into this phenomenon goes back to the pioneering British neuroscientist William Grey Walter in the 1950s, and David and I have been working on it in our lab since 2012.

During the summer of 2022, tens of thousands of people visited the Dreamachine across the four capital cities of the UK. Our audiences were amazed by how vivid their experiences were, and how different they could be from each other. For the scientists and philosophers on the team – including philosopher Fiona Macpherson, and my Sussex colleagues David Schwartzman, Reny Baykova, James Alvarez, and Trevor Hewitt – this has provided a unique platform from which to launch a larger study into perceptual diversity in the larger population, part of which is The Perception Census. 

How can people take part in it? 

It’s easy. You can sign up here and get going straight away. The Perception Census consists of a series of fun and engaging online games, brain teasers and interactive illusions. There are ten different sections, each covering a different aspect of perceptual experience, such as color, time, vision, sound and music, the body, how our expectations affect our experience, and much more. All you need is your own desktop computer or laptop, and you have to be at least 18 years old.  Every person taking part really does make a difference.

What do you hope citizen scientists involved in The Perception Census will take away from it? 

Many things! The warm glow of having contributed meaningfully to cutting-edge research in the science of perception, obviously. But perhaps even more important, by taking part, every participant will learn more about their own powers of perception, how they relate to others, and some of the fascinating questions that are still a mystery to all of us.

If enough people participate, our findings could rewrite our understanding of how we perceive the world, forming a unique body of scientific and philosophical research that will be valuable for years to come.  We live in highly polarized times, our beliefs and ideas sharpened within the echo chambers of rampant social media. Bringing to light our inner diversity could provide a powerful corrective against these corrosive forces by cultivating a new humility about our own perspectives. Recognizing that we don’t see the world as it is, but as we are, might provide a new platform for empathy, understanding, and communication. It could even be that engaging people in simple perceptual exercises that reveal the constructed nature of perception will open their minds to new viewpoints and help resolve disagreements.

There are also interesting connections to the concept of neurodivergence, which – like perceptual diversity – emphasizes that people differ in their perceptual experiences, and that differences are not deficits. For better or worse, neurodivergence has become associated with specific conditions, such as autism or ADHD, ironically reinforcing the view that these conditions stand in contrast to a neurotypical, ‘correct’ way of perceiving. By focusing on the middle ground that applies to all of us, the concept of perceptual diversity usefully challenges this interpretation.


Beyond all of this, my deep hope – given life by what we’ve observed in the Dreamachine – is that participants in the Census will discover a new sense of wonder about the everyday miracle of conscious experience, of how much is going on within our brains and bodies to create the experience of a world around us and of being a self within it.

Why is citizen science important? 

Most of my career has been about lab-based research, coupled with increasing amounts of public engagement activity. The Perception Census has been a new and exciting opportunity for me and my team. One of the obvious things citizen science delivers is scale. More than 12,000 people have already taken part in the Census, and we’re hoping for many, many more. This scale doesn’t just provide better data, it opens up entirely new questions. There would be no way of mapping out perceptual diversity through lab-based studies, however many we did. 

Citizen science also delivers meaningful engagement. When people contribute to the research, they get interested in the research, and curious about the deeper, underlying issues in science and philosophy. Once a flame of curiosity has been ignited, who knows where it will lead.

There is also the serendipitous, the unexpected. In the Dreamachine, we’ve been astonished by some of the descriptions of peoples’ experiences, and what they have meant to them. For example, many people told us that the Dreamachine experience helped them deal with challenging experiences like depression and grief, and their descriptions are now forming the basis of new lab-based research. I don’t yet know whether something similar will happen with The Perception Census, but I’m eager to find out – and we’ve already had some brilliant feedback:   


"I genuinely had such a wonderful weekend participating in this. Considering the themes it covers, I honestly wish it was as mandatory as our actual census."

"Guess who found out they have synaesthesia today. When I picture a week, I see a circle, and each day is a segment of the circle. I only found out because I took part in the Perception Census."

"This is the internet at its best, this is what the internet was intended for when it was invented. There are many parts of the internet that it is worth hanging on for and searching out and this is one of them."

What do you enjoy most about engaging the public in your research?

It’s so rewarding. I’m lucky to study a subject – consciousness – that many people find intrinsically interesting, but pretty much any area of science is deeply fascinating if presented in the right way.


I enjoy the challenge of figuring out how to convey the science and philosophy in an accessible way, without dumbing it down, and drawing out its relevance for people’s everyday lives. I enjoy how this challenge plays out in different ways across different formats, whether its large-scale art-science projects, writing books, recording podcasts, or working with film and TV. I’m always learning, and there is joy to working across disciplines and with new people. The Dreamachine, for example, brought together architects, composers, engineers, creative producers, technologists, digital designers – as well as scientists and philosophers. And in another project, from a few years ago, I worked with the rap artist Baba Brinkman to create the ‘rap guide to consciousness’ – something I’d have never expected to do, not in a million years.

I strongly believe that public engagement also benefits the science itself. The exercise of distilling complex research into a concise and clear form forces me to understand the research better myself. It helps me see new connections, and sometimes new ideas come about through the projects themselves.

Like any skill, public engagement takes practice. I started by looking for opportunities to give talks wherever I could – which for me meant old peoples’ homes in San Diego, and then bars and cafes in Brighton. The more you do, the more you’ll learn what works and what doesn’t. And again, learning to communicate your research to the public will help enormously in how effective you can be in conveying your work to scientific colleagues too.

What advice would you give to other scientists who are considering looking to citizen scientists in their work?

Make sure you identify the right questions. What is it about your research that really requires large participation? And be sure that you’ll be able to get useable data, because the world out there is very different from the highly controllable environment of a lab.


Spend lots of time refining the offer. Make sure your writing is clear and accessible, and make sure that everything works seamlessly. This sounds trivial and maybe obvious, but it takes more work than you might think. What about involving people in the development and design process? This has been a hugely valuable process we’ve embraced in the Dreamachine program.

Figure out how to give back. People are busy and the attention economy is vicious. If someone is giving you their precious time – and their mind – it's important that they get more than just a thank you for helping science. In The Perception Census, we devoted a lot of effort to giving back by helping people learn about perception and consciousness, and offering feedback – either at the time of participation or in the future – about their own specific way of experiencing the world and how this relates to others. 


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