I wondered for probably the millionth time why I am always running late.

This time, I vowed, I was going to find out.

I turned to an obscure field of neuroscience for answers. The scientists who work on the problem of time in the brain sometimes refer to their area of expertise as “time perception” or “clock timing.” What they’ve discovered is that your brain is one of the least accurate time measurement devices you’ll ever use. And it’s also the most powerful.

When you watch the seconds tick by on a digital watch, you are in the realm of objective time, where a minute-long interval is always 60 seconds. But to your brain, a minute is relative. Sometimes it takes forever for a minute to be over. That’s because you measure time with a highly subjective biological clock.
Your internal clock is just like that digital watch in some ways. It measures time in what scientists call pulses. Those pulses are accumulated, then stored in your memory as a time interval. Now, here’s where things get weird. Your biological clock can be sped up or slowed down by anything from drugs to the way you pay attention. If it takes you 60 seconds to cross the street, your internal clock might register that as 50 pulses if you’re feeling sleepy. But it might register 100 pulses if you’ve just drunk an espresso. That’s because stimulants literally speed up the clock in your brain (more on that later). When your brain stores those two memories of the objective minute it took to cross the street, it winds up with memories of two different time intervals.

And yet, we all have an intuitive sense of how long it takes to cross a street. But how do we know, if every time we do something it feels like it a slightly different amount of time? The answer, says neuroscientist Warren Meck, is “a Gaussian distribution” - in other words, the points on a bell curve. Every time you want to figure out how long something is going to take, your brain samples from those time interval memories and picks one. (…)

Your intuitive sense of how much time something will take is taken at random from many distorted memories of objective time. Or, as Meck puts it, “You’re cursed to be walking around with a distribution of times in your head even though physically they happened on precise time.”

Your internal clock may be the reason why you can multitask. Because nobody - not even the lowly rat - has just one internal clock going at the same time.

At the very least, you’ve got two internal clocks running. One is the clock that tracks your circadian rhythms, telling you when to go to sleep, wake up, and eat. This is the most fundamental and important of all your internal clocks, and scientists have found it running even in organisms like green algae. The other clock you’ve likely got running is some version of the interval time clock I talked about earlier - the one that tells you how long a particular activity is going to take.

{ io9 | Continue reading }

photo { Logan White }

neurosciences, time | November 26th, 2010