Writing in the journal Science, they said an area of our brain called the pulvinar regulates signals between clusters of brain cells as our brain focuses on the people and objects that need our attention.
Like a switchboard operator, the pulvinar ensures separate areas of the visual cortex, which processes visual information, are communicating about the same external information, lead author Yuri Saalmann of the Princeton University Neuroscience Institute said.
Without the pulvinar's oversight, an important observation such as an oncoming bus as one is crossing the street could get lost in a jumble of other stimuli, the researchers said.
"A fundamental problem for the brain is that there is too much information in our natural environment for it to be processed in detail at the same time," Saalmann said in a Princeton release.
"The brain instead selectively focuses on, or attends to, the people and objects most relevant to our behavior at the time and filters out the rest."