Perception as controlled hallucination: why what we see is only a guess and how this can help us

To depict looking through a frame created by our own body

Everything is not quite as it seems.

This is according to Professor Anil Seth, a leading expert in cognition and consciousness, in his international bestseller, Being You.1 Published in 2021, Seth’s book brings together cutting-edge research on consciousness and how we make sense of the world around us and within us.

Seth posits that humans, and indeed all conscious creatures, have evolved to perceive things not as they are but rather in a way that’s helpful for their survival. So, everything we see, hear and feel is in fact a controlled hallucination.


Brains don’t see or hear anything, so must make an educated guess on what’s really out there

Imagine a brain. Trapped inside a dark skull, what does it really see or hear? Nothing. Instead, it relies merely on electrical impulses sent from sensory organs, like our eyes and ears. Our brains compare and combine these signals with prior expectations or beliefs to form a picture of the world around us and to predict how to react. Essentially, how we perceive the world is our brain’s best guess of what’s out there: a controlled hallucination.

And it’s not just external information that’s perceived this way, our brains also use guesswork to make sense of what’s going on inside our bodies too.2

Using sensory information from our organs, combined with past experience, our brains are able to create sensations of feeling thirsty, tired or hungry; a skill called interoception.

We’ve evolved like this because it’s a better use of our resources to be proactive in how we interact with our environment rather than reacting to it. We explain more on this in our post on body budgeting.


Optical illusions help illustrate how controlled hallucinations work

We can experience a controlled hallucination in action when we look at an optical illusion. A famous example is the checker shadow illusion. Conceived in 1995 by professor of Vision Science Edward Adelson, this visual trick uses our expectations of what we think we should see to fool us.

Looking at the image 1. below, does square A or B appear lighter? Most people see B as the lighter square, when in reality both are the same colour (see image 2.). This happens because the brain is using prior knowledge of the pattern of a checkerboard, combined with our understanding that a shadow dims the appearance of a surface, to make B seem lighter than it is.

Image 1

Image 2

Images by Adrian Pingstone, based on an original image by Edward H. Adelson3


Our brains do a good job of providing us an accurate picture of reality, but not always

In general, our brains are very good at providing us with a useful and relatively accurate picture of reality. But not all the time.

As we saw in the example above, sometimes the brain can be tricked. Similarly, in some mental illnesses what the brain is predicting can become unhelpful to a person’s overall wellbeing. Recent research suggests that people with depression tend to make too many unhelpful predictions or disregard helpful information that contradicts negative expectations.4 The result is a prolonged unhelpful perception of the world and their place within it.

In his book, The Way Out, psychotherapist Alan Gordon theorises that chronic pain is another example of the brain’s prediction process going awry.5 The nervous system of people who experience persistent pain unintentionally constructs their pain because of mistaken guesses that they’re in some way under threat. A vicious cycle of feedback forms, where pain is the reaction to benign stimuli.


We can use the new understanding of controlled hallucinations to our advantage

This new understanding of how perception works can provide us with vital clues of how to deal with life’s challenges. Recognising that our moods, feelings and emotions are in part best guesses, but not necessarily accurate reactions, opens the door to changing the way we feel and react to situations.

This can apply not only to clinically-diagnosed conditions, such as depression or forms of chronic pain, but can help us overcome unhelpful everyday patterns of behaviours or habits, such as eating too much or exercising too little.


Perception as controlled hallucination: find out more

If you’d like to find out more about perception as controlled hallucination, as well as other theories on consciousness, the following websites are a great place to start:


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Sources and references

Photo by cottonbro from Pexels.

  1. Anil Seth: Being You
  2. Seth AK, Friston KJ. Active interoceptive inference and the emotional brain. Philos Trans R Soc Lond B Biol Sci. 2016 Nov 19;371(1708):20160007
  3. Adelson, Edward H. (2005)
  4. Kube T, Schwarting R, Rozenkrantz L, Glombiewski JA, Rief W. Distorted Cognitive Processes in Major Depression: A Predictive Processing Perspective. Biol Psychiatry. 2020 Mar 1;87(5):388-398. doi: 10.1016/j.biopsych.2019.07.017. Epub 2019 Jul 29. PMID: 31515055.
  5. Ashar YK, Gordon A, Schubiner H, Uipi C, Knight K, Anderson Z, Carlisle J, Polisky L, Geuter S, Flood TF, Kragel PA, Dimidjian S, Lumley MA, Wager TD. Effect of Pain Reprocessing Therapy vs Placebo and Usual Care for Patients With Chronic Back Pain: A Randomized Clinical Trial. JAMA Psychiatry. 2022 Jan 1;79(1):13-23. doi: 10.1001/jamapsychiatry.2021.2669. PMID: 34586357; PMCID: PMC8482298.