It might seem impossible to identify a dozen images flashing by in a fraction of a second.
But a team of neuroscientists has found that the human brain can do just that at record-breaking speed.
U.S. researchers discovered that the human brain can interpret images that the eye sees in just 13 milliseconds – the first evidence of such rapid processing speed.
That speed is almost eight times faster than the 100 milliseconds recorded by previous studies.
Researchers asked subjects to look for a particular type of image, such as picnic or smiling couple, as they viewed a series of six or 12 pictures, each presented for between 13 and 80 milliseconds.
‘The fact that you can do that at these high speeds indicates to us that what vision does is find concepts,’ said Mary Potter, an MIT professor of brain and cognitive sciences and senior author of the study.
‘That’s what the brain is doing all day long – trying to understand what we’re looking at,’ she added.
This rapid-fire processing may help direct the eyes, which shift their gaze three times per second, to their next target, Professor Potter explained in the study, published in the journal Attention, Perception, and Psychophysics.
‘The job of the eyes is not only to get the information into the brain, but to allow the brain to think about it rapidly enough to know what you should look at next.
‘So in general we’re calibrating our eyes so they move around just as often as possible consistent with understanding what we’re seeing,’ she said.
After an image ‘hits’ the retina, the information such as shape, colour, and orientation is processed by the brain.
The study suggests that while the images are seen for only 13 milliseconds before the next image appears, part of the brain continues to process those images for longer than that.
‘If images were wiped out after 13 milliseconds, people would never be able to respond positively after the sequence. There has to be something in the brain that has maintained that information at least that long,’ Professor Potter said.
She previously found that humans can correctly identify images seen for as little as 100 milliseconds, but her new research suggests we can do this almost eight times faster.
In the new study, the researchers gradually increased the speed of images until they reached a point where subjects’ answers were no better than if they were guessing.
