How does imagination really work in the brain? New theory upends what we knew
by The Conversation
Grandfailure/Getty Images
Your brain is currently expending about a fifth of your body’s energy, and almost none of that is being used for what you’re doing right now. Reading these words, feeling the weight of your body in a chair – all of this together barely changes the rate at which your brain consumes energy, perhaps by as little as 1%.
The other 99% is used on the activity the brain generates on its own: neurons (nerve cells) firing and signalling to each other regardless of whether you’re thinking hard, watching television, dreaming, or simply closing your eyes.
Even in the brain areas dedicated to vision, the visuals coming in through your eyes shape the activity of your neurons less than this internal ongoing action.
In a paper just published in Psychological Review, we argue that our imagination sculpts the images we see in our mind’s eye by carving into this background brain activity. In fact, imagination may have more to do with the brain activity it silences than with the activity it creates.
Imagining as seeing in reverse
Consider how “seeing” is understood to work. Light enters the eyes and sparks neural signals. These travel through a sequence of brain regions dedicated to vision, each building on the work of the last.
The earliest regions pick out simple features such as edges and lines. The next combine those into shapes. The ones after that recognise objects, and those at the top of the sequence assemble whole faces and scenes.
Neuroscientists call this “feedforward activity” – the gradual transformation of raw light into something you can name, whether it’s a dog, a friend, or both.
In brain science, the standard view is that visual imagination is this original seeing process run in reverse, from within your mind rather than from light entering your eyes.
So, when you hold the face of a friend in mind, you start with an abstract idea of them – a memory or a name, pulled from the filing cabinet of regions that sit beyond the visual system itself.
That idea travels back down through the visual sequence into the early visual areas, which serve as your brain’s workshop where a face would normally be reconstructed from its parts – the curve of a jawline, the specific shade of an eye. These downward signals are called “feedback activity”.
A signal through the static
However, prior research shows this feedback activity doesn’t drive visual neurons to fire in the same way as when you actually see something.
Even behind closed eyes, early visual brain areas keep producing shifting patterns of neural activity resembling those the brain uses to process real vision.
Imagination doesn’t need to build a face from scratch. The raw material is already there. In the internal rumblings of your visual areas, fragments of every face you know are drifting through at low volume. Your friend’s face, even now, is passing through in pieces, scattered and unrecognised. What imagining does is hold still the currents that would otherwise carry those pieces away.
All that’s needed is a small, targeted suppression of neurons that are pulled by brain activity in a different direction, and your friend’s face settles out of the noise, like a signal carving its way through static.
Steering the brain
In mice, artificially switching on as few as 14 neurons in a sensory brain region is enough for the animal to notice it and lick a sugar-water spout in response. This shows how small an intervention in the brain can be while still steering behaviour.
While we don’t know how many neurons are needed to steer internal activity into a conscious experience of imagination in humans, growing evidence shows the importance of dampening neural activity.
Other lines of evidence strengthen our theory, too. About one in 100 people have aphantasia, which means they can’t form mental images at all. One in 30 form these images so vividly they approach the intensity of images we actually see, known as hyperphantasia.
Research has found that people with weaker mental imagery have more excitable early visual areas, where neurons fire more readily on their own. This is consistent with a visual system whose spontaneous patterns are harder to hold in shape.
Taking all this together, the spontaneous activity reshaping hypothesis – our new theory that imagination carves images out of the steady stream of ongoing brain activity – explains why imagination usually feels weaker than sight. It also explains why we rarely lose track of which is which.
Visual perception arrives with a strength and regularity the brain’s own internal patterns don’t match. Imagination works with those patterns rather than against them, reshaping what is already there into something we can almost see.
※ Picks respects the rights of all copyright holders. If you do wish to make material edits, you will need to run them by the copyright holder for approval.
more from
The Conversation
The Conversation
Many churches, synagogues and mosques are built around families - and they're struggling to respond to rising singles
2026-04-26 00:00:00
The Conversation
'More shearwaters are washing up dead on Australian beaches. It’s not due to 'natural' causes'
2026-04-26 00:00:00
The Conversation
How to protect your hobbies in a culture that wants to exploit them
2026-04-25 00:00:00
The Conversation
Why the Southeast is burning - extreme drought is only part of the reason
2026-04-25 00:00:00
BEST STORIES
KoreaJoongAngDaily
Click-clack: In high-pressure Korea, young people find stress relief in keycaps
2026-04-24 00:00:00
Knowable Magazine
Life after cancer treatment is different. So are the health needs.
2026-04-23 00:00:00
AllblancTV
Only 10 MIN! Full Body Fat Burning Workout (1/3)
2026-04-20 00:00:00
The19th
Should you try cold plunging?
2026-04-21 00:00:00
Lifestyle
The Conversation
'Will oil prices ever truly go back to normal?'
2026-04-23 00:00:00
The Conversation
6 ways your smartwatch is lying to you, according to science
2026-04-23 00:00:00
The Conversation
The best books about being a teenager - according to our experts
2026-04-22 00:00:00
The Conversation
Are aliens real? Scientists have been hunting for extraterrestrial life since the time of Aristotle
Grandfailure/Getty Images 
Reference
