Scientists have explained what we already knew -- that refs aren't perfect -- and help explain why:
"Our memories just aren't cut out to allow us to be perfect referees," says Gary Marcus, a professor of psychology at New York University and author of the book "Kluge: the Haphazard Construction of the Human Mind." "Our eyes work a lot like cameras but our memories don't work anything like an SD (secure digital) card. We can't literally play back what we just saw."
David Meyer, director of the University of Michigan's Brain, Cognition and Action Laboratory, says the maximum number of players any one person could carefully track was four. When referees do miss a crucial piece of evidence, their brain will fill in the gaps using past experiences to help them make the call. "Filling in is really a deeply embedded part of human consciousness," Marcus says.
Just as a driver's brain would tell him a car was in his blind spot even though he could not see it, referees' brains would fill in what was missing, he said.
"Human beings are never going to be perfect at making calls," says Marcus. "Our memories just aren't cut out to allow us to be perfect referees."