Dear Science,

I need answers. Why does my mind suddenly, and often, flash back to random memories? Like right now, I'm sitting at work, and my mind flashed to a small patch of grass with a blackberry bush that's next to a creek and a historic brick building in the tiny Trinity County town of Weaverville. I was in this exact spot like 10 years ago. I can't think of anything that triggered it. It happens to me all the time—not this particular memory, of course. I get all sorts of random flashbacks spanning my entire life. Does this happen to everybody? What the hell?

These memories probably aren't quite as random as they seem. Rather, some small trigger is probably resurrecting them from deep in your brain. A smell, a sound, a pattern, or color of light connected your present moment to the past.

Memory, particularly this sort of associative memory, preceded even intelligence; it's operating on a very deep level in your brain and thus able to interject itself into your conscious mind, flooding out your thoughts at the present with recollections from the past.

Take just about any vertebrate and expose it to a paired stimulus (a bell) and event (some food), and the brain of the organism will start making connections, bringing up the memory of the event when the stimulus hits again. This sort of memory is incredibly useful as a scratch pad for life—allowing organisms to adapt to new environments with ease. After smelling something, eating it, and getting sick, this is the way a beast can remember to not eat after that smell in the future. Science suspects the smell of Axe body spray will soon induce similar feelings of revulsion in straight women everywhere, by the same mechanism.

B. F. Skinner, an American scientist, made a career out of fussing with this sort of memory, creating an entire scientific philosophy—radical behaviorism. The magnificent bastard came up with a delightful experiment showing how powerful this mechanism is in animals. He placed hungry pigeons in a box. After 15 seconds, no matter what the birds did, they received food; nothing the birds did made the food more or less likely to appear. The pigeons developed little rituals anyway—desperately spinning around counterclockwise, tossing their heads back, or swinging their whole bodies generally in one place in the box—falsely associating these prior actions with the appearance of food. People are animals. (Like clockwork oranges, some might say.) When there's no explanation for this or that happening, people also become superstitious. Indeed, Skinner's experiment with the pigeons may very well show the real source of religion.

Science idly wonders if this is why intelligence evolved—to sort out the true connections from the false. Once you start considering causality—did this really cause that to happen—you've got a powerful filter to clear out all of the junk.

Causally Yours,


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