Time flies when you’re having fun. ~ Anonymous
I have noticed that when I am involved in activities that are interesting to me, time feels like it passes quickly. In other words, I can do a lot of activities, and not notice the passage of time. However, when I reflect later on the passage of time, periods of my life in which I was busiest doing work that interested me, it feels like those are the parts of my life I remember most, and which seem upon reflection to have passed most slowly.
Here is my theory; our experience of the passage of time is based on the memories we build as time passes. I don’t currently know of any research which supports my theory, but read my thoughts below and see what you think.
When we are bored, or doing tasks which we have done many times before, our brain does not develop as many memories of those experiences. As a result, our short term memory does not engaged as often, and so has more references points with which to measure the passage of time. For our short term memory, this means that time feels like it is passing slowly. In other words, we are able to actively check the passage of time more frequently because our brains have the cognitive load available to do so, and so time feels like it is passing more slowly. In contrast, when we do activities in which our whole minds are actively engaged, our brain stops to check the time less frequently because it does not have the cognitive resources to do so and process our current experiences.
However, when we reflect back on the passage of time, our brains look for activities we have done and their associated memories. During periods of our lives when we are most mentally active (such as changing a job, becoming a parent, or moving to a new part of the world), the passage of time seems the slowest as we have more new memories to check through. When our lives are dull and full of the routine, our brains literally store less information from our life, and upon reflection it seems that the passage of time is very fast since there are hardly any memories with which to measure the passage of time.
Consequently, if you want to be able to reflect back on your life and feel like it is passing slowly, you need to build lots of new memories and avoid sticking to only routine tasks. Consider changing your job frequently, moving to a new place, and trying out new experiences. If none of this is possible, consider other changes you can make such as commuting to work with a different path (or a different mode of transport) every day, deliberately eating new food each day, or anything else that breaks your daily routine on a regular basis.