What time is it? That may well be the first question you ask yourself every day. Time decides everything and continues to be an enigma, as Jesperson and Fitz-Randolph (1977) wrote already. Our subjective perception of time is fascinating: although some of us are quite good at guessing the time, still we are all sensitive to all sorts of distortions.

Time flies when you’re having a good time and is dragging when you are waiting, scared, or bored. Time seems to move ever faster as you get older, and we are all short of it. Which of us does not regularly wish we had an extra day, week or even month while the rest of the world is standing still?

We all experience pressure of time, although as a student this week you will at last feel a small lull now that the exams are behind you, whereas I as a lecturer make the most of every hour now that lectures are beginning again. The way in which time is experienced is quite variable, then, both between and within individuals.

“We listen less and less to our internal biological clock”

Mankind has been striving for thousands of years to learn how to measure time objectively and has developed increasingly more sophisticated instruments to do so: sundials, hourglasses, water clocks, Huygens’ pendulum clock according to Galileo’s insight into the pendulum (gained while staring through sheer boredom at swinging chandeliers during mass), Harrison’s chronometer (essential to the shipping trade), quartz clocks and our current standard for time, the atomic clock. So much technological innovation to know accurately and reliably what time it is, in spite of changing conditions - temperature, pressure and humidity.

One second now lasts precisely 9,192,631,770 cycles between two energy states in the cesium-133 atom. Yet all that time there was a clock running inside us - robust and resistant to high fever and hypothermia, action and tedium, hunger and thirst; aware of the right time of day, the right month in the year; correcting itself on a daily basis and conducting the psychological, physiological and biochemical processes in our bodies: our internal biological clock. The paradox is that it appears as if we have learned to listen to it less and less over all those years. Perhaps we can make this the object of our next innovation?

Yvonne de Kort is professor of Environmental Psychology at Human-Technology Interaction