What is Time?
In his famous book, The Confessions, written in the year 400 AD, St. Augustine asks, “What then is time? If no one asks me, I know what it is. If I wish to explain it to him who asks, I do not know.” We all experience change and motion and we know that these are not possible without time. Although we feel that we have a ‘sense of time’, our bodies are not equipped with a sensory organ for detecting the passage of time in the same way that we have eyes and ears for detecting light and sound. A table or a chair are objects that exist and can be sensed, but as the eminent French Psychologist Paul Fraisse pointed out, “Duration has no existence in and of itself.” Time, it seems, is the ultimate illusion.
So how do we sense time? We see shapes and colors, we hear sounds and feel the texture. Yet we know that even if we close our eyes and shut down all our senses, we can still sense the passing of time through the changing pattern of our thoughts. Time is surely then related to the rate of change. Without change, time would not exist, and everything would happen all at once.
Time is, therefore, an indispensable feature of the way we perceive the world. We see, hear, feel, and think ‘now’. What is experienced is experienced in the present moment. It is a moment in time between a ‘no more’ and a ‘not yet’. You might think that a ‘now’ moment is instantaneous, having no duration, but it is not. If it was, we would not feel any continuity in the flow of time. When we experience the flow of time, we do it through an event that is first anticipated, then experienced, and eventually remembered.
If you are familiar with the Beatles song ‘Hey Jude’, for instance, the moment you hear ‘Hey’, you cannot help but hear the ‘Jude’ already. The ‘Jude’ is somehow present in your mind even though it is still anticipated in reality. Try it out and mentally sing these two words. As soon as you start with ‘Hey’, you immediately hear ‘Jude’ in your mind. Likewise, when you hear ‘Jude’, the ‘Hey’ is still somehow present in your memory, even though it is no longer sensed.
This integration of past, present, and future within an ‘experienced moment’ is what maintains our sense of time continuity. The flow of ‘experienced moments’ or ‘nows’ provides the basis of our consciousness and subjective present. They are the fundamental elements that compose the train of our thoughts. So how long is an ‘experienced moment’? What is the duration of a present ‘now’?
Short-Term Memory Clue
One clue for the duration of an experienced moment comes from the capacity of our short-term memory. Short-term memory is a mental system that stores temporary information for immediate use and manipulation. Our short-term memory capacity is defined as the amount of information we can hold in our minds without losing it in the presence of other information or distractions. Attempting to store more information above that capacity limit will result in losing the previous items. Now scientists have estimated that information is normally stored in short-term memory for about 2 to 5 seconds. Afterward, the information is either forgotten if you do not need it anymore or is stored in our permanent long-term memory.
In a seminal paper, the eminent French experimental psychologist Paul Fraisse summarized the experimental findings of the last few decades and concluded that the present ‘experienced moment’ is a duration that can hardly extend beyond 5 seconds and has an average value of 2 to 3 seconds. Three seconds is the length of time that an average person can keep something in his mind before having to store it in his long-term memory. If someone verbally told you his 10-digit phone number and asked you to dial it, you would most likely be able to do that if you manage to do it within 3 seconds.
The 3 -second ‘nows’
It is therefore not by chance that the 3-second interval happens to show up in many areas of our lives. In songs and classical music, musical phrases blend nicely when they are made of musical motifs that are around 2 to 3 seconds long. The famous musical motif in Beethoven’s 5th Symphony, the one that sounds like fate is knocking on your door, is around 3 seconds long. The same is true for poetry: the average duration of a spoken verse in most languages corresponds to about 3 seconds. This seems to be a universal phenomenon. Try that with any of Shakespeare’s famous sonnets, ‘Shall I compare thee to a summer’s day?” Time yourself as you read it aloud and you will find it takes around 3 seconds. Radio stations use 3-second stings as breaks in a radio program. The soothing sound you hear at the startup of a Windows or Apple computer is 3 seconds long. Relaxation breathing takes about 3 seconds. In most cultures, a handshake lasts about 3 seconds. A hug also lasts for around the same duration!
Three seconds, that’s just about the duration of the “present now”.
For more on that check out my book “The Power of Time Perception” to learn more how we perceive time and the factors that affect the speed of time in your mind.