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The good news is that time doesn’t speed up as you get older, but the bad news is that you simply experience less of it as the processing power of your brain decreases – at least, that’s according to a new paper published this week in the journal European Review.
The older we get, the more it feels like the sands of time are falling at an exponentially increasing rate, accelerating us all towards entropy. An explanation for this phenomenon has now been put forward by study author Adrian Bejan from Duke University, who says that discrepancies between “clock time” and “mind time” are responsible for the apparent hastening of our lives.
In a statement, Bejan said that "the human mind senses time changing when the perceived images change." In other words, "the present is different from the past because the mental viewing has changed, not because somebody's clock rings.”
In his paper, he writes that “the rate at which changes in mental images are perceived decreases with age,” and that because children are able to receive and process more mental images per second than adults are, their days feel like they are packed with more time.
The human eye is constantly on the move, and as soon as it has processed an image it switches its focus to something else. These rapid movements of the eye are called saccades, and are separated by short stationary periods called fixations, during which the eye fixes its gaze on a particular image.
Previous research has shown that the eye of an average adult makes three to five saccades per second, punctuated by fixations of 200 to 300 milliseconds. Yet fixation times are significantly shorter for children, who are therefore able to make more saccades and take in more images per second.
The reason for this change in fixation time is that as we age, it starts taking longer for our brains to process the information being received by the retina. According to Bejan, this is because we develop increasingly complex neural networks as we get older, which means that signals have further to travel in order to reach separate parts of the brain. Degradation to neuronal pathways also means that these electrical signals experience more resistance, so are slowed down.
An analogous explanation would be to say that we experience our lives like time-lapse photography. The more photos that are captured per second, the slower the movement of time appears. Yet as we start to increase the interval between each photograph, the more movement occurs between each frame, giving the illusion that events are occurring faster.
