To the young, summer seems to stretch out endlessly. Long days make time feel expansive. By middle age, though, the days can blur into each other. June becomes September at a rate disconcerting enough to make you wonder if it’s at all possible to slow time down.

There is, of course, one obvious way to stop the acceleration. Studies of subjective time perception find that unpleasant activities, such as waiting in an airport security line, or suffering through a bout of food poisoning, do indeed make the seconds feel miserably long.