London: When it comes to vision, the brain can perform more than one function without sacrificing time or accuracy.
Researchers at the University of California, Santa Barbara (UCSB) and the University of Bristol in Britain have shown that during visual sampling – the act of picking up bits of visual information through short glances – the brain can handle various visual functions simultaneously.
To support their findings, they looked at two vision processes: foveal analysis and peripheral selection.
When something catches your attention, you swing your gaze to it – allowing for closer inspection – known as foveal analysis.
This process helps you read, examine and search for specific objects or people. Whatever falls outside that narrow zone becomes blurry and less distinct, said the study published in the journal Proceedings of the National Academy of Sciences Plus.
But when looking for something – say, a specific book among a group of books on a shelf, or a prescription in a medicine cabinet, or even a friend in a crowd, you use peripheral vision.
“Though you might not be aware, your brain is evaluating and deciding where to direct your gaze as you decide whether or not the thing you are focused on is the object you have been seeking,” said Miguel Eckstein, professor in the department of psychological and brain sciences at UCSB.
Eckstein, along with professors Casimir JH Ludwig and J Rhys Davies of University of Bristol, discovered that the human brain has the capacity to perform both functions – foveal analysis and peripheral selection – rapidly and accurately, at the same time and independently.
Using an eye-tracker, they monitored the accuracy of both the observers’ foveal and peripheral perceptual judgments and their point of gaze.
The researchers visualised how the brain utilises information through time to direct the gaze and to influence the foveal perceptual judgments.
“The brain would have to either do one task at a time – slowing the total time to complete both – or do both at the same time but not as well on each of them,” said Eckstein.
However, the results of these tests demonstrated that neither process was interrupted or slowed by the other.
This specialised ability to perform both tasks involved in visual sampling may have to do with the sheer amount of time humans spend visually sampling their environment.
A normal human being performs nearly 10,000 eye movements daily, much of which is spent doing both foveal analysis and peripheral selection.
“We do not know if this is innate or arises from experience in early life, or both,” said Eckstein.