Berkeley -- A new study by vision scientists at the University of California, Berkeley, finds that the human visual system is better able to discriminate the movements of a single person when his or her actions are coordinated in a meaningful way with a second individual.
When shown a pair of figures in motion, for instance, the brain is better able to pick out an individual if it perceives that one person is throwing a punch while another is making a defensive block, the researchers said.
This is especially important when the view is somehow obscured or impaired, according to the study, published in the September issue of the journal Nature Neuroscience.
"Our study reveals a greater degree of complexity in human visual processing than previously understood," said Dennis Levi, UC Berkeley dean of optometry and principal investigator of the study. "When we watch two people interacting, knowing what one is doing helps us understand the actions of the other. We think of it as 'It takes two to Tango.'"
Other researchers on the team are Peter Neri, a UC Berkeley post-doctoral fellow in Levi's laboratory, and Jennifer Luu, an undergraduate who joined the group as part of the UC Berkeley Undergraduate Research Apprentice Program. Luu is now a UC Berkeley Ph.D. student in bioengineering.
This research provides insight into how accurately we can interpret what we see from grainy security cameras, particularly when identifying whether a crime is taking place. There is even research taking place on the development of artificial intelligence computer programs that can automatically detect which actions are suspicious.
At its most fundamental level, the human brain's ability to interpret and react to the action it sees within a fraction of a second is a matter of life and death, such as identifying that a tiger lunging forward with teeth bared is a threat and then deciding how best to get away.