Babies show 'intuitive physics' evidence EVANSTON, Ill., Jan. 28 (UPI) -- Intuitive physics occurs in infants as young as 2 months -- the earliest age at which testing can occur, U.S. researchers suggested. Lead author Susan J. Hespos, associate professor of psychology at Northwestern University's Weinberg College of Arts and Sciences, said intuitive physics includes skills that adults use all the time -- such as when a glass of milk falls off the table, one might try to catch the cup, but not likely try to catch the milk. One doesn't have to think consciously about what to do because the brain processes the information and one reacts, Hespos explained. Hespos and colleagues conducted a review of the literature and found infants show an understanding that unsupported objects will fall and that hidden objects do not cease to exist. By 5 months, infants have an expectation that non-cohesive substances like sand or water are not solid. "I think liquid is the best example of a non object that you interact with -- a baby has to drink liquid every single day," Hespos said in a statement. It's a universal experience with milk or water. We did studies on whether babies expected water to pour or tumble from an upended cup. By 5 months of age, babies expect both water and sand to pour, so we have clear evidence that this type of physical knowledge is available early in development. The findings were published in Cognitive Science.