One of the common psychological explanations behind our sense of time moving faster with age is that the more familiar the perceptual information around us is, the less attention we pay to it. Children, for example, are constantly perceiving new events and environments, using significantly more brain power to process day-to-day information. As we get older, the novelty of our reality slowly tapers off, leaving one with the sense that time is passing more rapidly.
Adrian Bejan, a mechanical engineer at Duke University, has taken this idea and offered a more solid, physical explanation to underpin the phenomena. While we certainly may have processed more information when we were young, giving us the sense of time moving slower, Bejan he claims this to be the result of younger brains being able to identify and integrate mental images at a much more rapid pace.