Only a tiny fraction of your visual field is captured in colour
(Image: Suren Manvelyan/Rex Features)
Read more: “The grand delusion: Why nothing is as it seems“
Your senses are your windows on the world, and you probably think they do a fair job at capturing an accurate depiction of reality. Don’t kid yourself. Sensory perception – especially vision – is a figment of your imagination. “What you’re experiencing is largely the product of what’s inside your head,” says psychologist Ron Rensink at the University of British Columbia in Vancouver, Canada. “It’s informed by what comes in through your eyes, but it’s not directly reflecting it.”
Given the basic features of your visual system, it couldn’t be any other way. For example, every 5 seconds or so, you blink. Yet unless you’re thinking about it, as you probably are right now, you don’t notice the blackouts because your brain edits them out.
Blinking is just the tip of the iceberg. Even when your eyes are open they’re only taking in a fraction of the visual information that is available.
In the centre of your retina is a dense patch of photoreceptor cells about 1 millimetre across. This is the fovea, the visual system’s sweet spot where perception of detail and colour is at its best. “When you move away from the fovea, visual acuity falls away really quickly, and colour vision disappears,” says Rensink. About 10 degrees to the side of the fovea, visual acuity is only about 20 per cent of the maximum.
What that means is you can only capture a tiny percentage of the visual field in full colour…
