Take a quick look at the white object above.
Did you see the seahorse? Chances are, even if you didn't see the image (hint: look at the black space this time), your brain still knew it was there.
According to research published in the journal Psychological Science, our brains pick up on images that we never consciously perceive.
Volunteers were shown a series of black-and-white images while hooked up to an EEG device that recorded their brain activity. Each image was shown for just under two-tenths of a second. Then the subject pressed a button to indicate if the object was something familiar (like a turtle or telephone) or novel (a random shape that they didn't recognize).
The team wanted to know what the brain does with images that are right in front our eyes but that we don't consciously see, like this seahorse. That's where the EEG testing comes in. About 400 milliseconds after subjects looked at the silhouette, a wave called a N400 was recorded by the EEG device, said lead researcher Jay Sanguinetti, a doctoral candidate at the University of Arizona. The appearance of that brainwave suggests that the brain is processing something meaningful.
So even though the majority of the subjects said they didn't notice the background images at all (some didn't believe they were there even when shown them after the study, notes Sanguinetti), their brains still produced the N400 wave.
If our brain recognizes that meaningful objects are right in front of us, why don't we notice them? "We think what's going on there is that potential objects in the visual scene—the novel white shape and the seahorses on the outside—enter into this competitive process, so they are literally competing for neural space in the brain," said Sanguinetti.
Source material from National Geographics