My fellow blogger Amanda tweeted this yesterday morning during her commute:
If cold makes matter contract, why did the sidewalk between me and the metro seem twice as long this morning?
She was mostly right in her assumption that cold makes things contract (though thermal expansion isn't uniform, and there are substances, like water, that expand when they freeze), but that wasn't really the issue. Hers was one of perception. Time and distance in this situation hadn't changed, but emotions probably had.
Last year, two researchers from the Paris School of Economics, writing in the Philosophical Transactions of the Royal Society B, promoted a new theory about how we perceive time. "Instead of considering an 'internal timer' that gives rise to differences in time perception," they wrote, "we adopt the idea that individuals 'experience' time." A big part of that experience is emotions, and the researchers theorize that the more positive an anticipated emotion, the slower that time will pass.
If a person is waiting for something pleasant to occur, say, opening presents on Christmas morning or entering a warm Metro station after a long, chilly walk, she will experience positive emotions like joy that will improve the situation. Time will seem to expand, and she will experience impatience.
But if a person is awaiting a negative experience, like a trip to the dentist or having to make that chilly walk, she will experience experience negative emotions such as grief or frustration. Time will seem to pass more quickly, but she will undergo anxiety.
"Time is not absolute," the researchers write, "but can rather have a certain 'elasticity' or the person, which will depend on the kind of emotions she experiences."