How does our brain keep track of time?

Question

Last night I went to bed sorta late and forgot to set an alarm, but I remember thinking it’d be nice to wake up around nine.

I woke up at EXACTLY 9 AM – literally to a minute. Could be a coincidence, except I do tend to wake up around nine on most days, with or without an alarm. Only exceptions are when I go to bed extremely late and force my body to take longer to recover, I suppose.

Made me think of my late Grandma who kept telling me how she can set an alarm in her head and wake up at any time she wants. I always thought it’s bullshit.

I mean, if that was true, how would that even work? Time is a concept, and a relatively new one at that; IIRC we only started really counting minutes and seconds around the Industrial Revolution? Of course there’s sunrises and sunsets and the whole natural circadian rhytm thing, but most people are detached from it anyway.

Does our brain learn to count hours and minutes somehow because our lives revolve around that so much? Is it all just a big ol’ bias of some sort?

In: 17

Answer 1

Our brains have a built-in mechanism for keeping track of time, which is called the circadian rhythm. This is a biological process that helps our bodies regulate various functions, including sleep and wakefulness, over a 24-hour period. This process is driven by the release of certain hormones, such as melatonin, in response to changes in light exposure.
In addition to the circadian rhythm, our brains also have other mechanisms for keeping track of time. For example, our brains can use sensory information, such as the position of the sun in the sky or the sound of a clock ticking, to estimate the passage of time. Our brains are also able to use past experiences to predict how long certain events should take, which can help us keep track of time in the absence of external cues.
It’s possible that your ability to wake up at a specific time without an alarm is due to your brain’s ability to keep track of time using these mechanisms. It’s also possible that your brain has learned to anticipate when you usually wake up and has adjusted your sleep patterns accordingly.
Overall, our ability to keep track of time is a combination of biological processes and learned behaviors, and it’s an important part of how we function in the world.