Kluge: The Haphazard Construction of the Human Mind (Houghton Mifflin; 2008)

Contextual memory has its price, and that price is reliability. Because human memory is so thoroughly driven by cues, rather than location in the brain, we can easily get confused. The reason I can't remember what I had for breakfast yesterday is that yesterday's breakfast is too easily confused with that of the day before, and the day before that. Was it yogurt Tuesday, waffles Wednesday, or the other way around? There are too many Tuesdays, too many Wednesdays, and too many near-identical waffles for a cue-driven system to keep straight. (Ditto for any pilot foolish enough to rely on memory instead of a checklist — one takeoff would blur together with the next. Sooner or later the landing gear would be forgotten.)

Whenever context changes, there's a chance of a problem. I, for example, recently found myself at a party where I was awestruck by the sudden appearance of the luminescent and brilliantly talented actress who played the role of Claire Fisher in the television show Six Feet Under. I thought it would be fun to introduce myself. Ordinarily, I probably would have had little trouble remembering her name — I'd seen it in the credits dozens of times, but at that moment I drew a total blank. By the time I got a friend to remind me of her name, the actress was already leaving; I had missed my chance. In hindsight, it's perfectly clear why I couldn't remember her name: the context was all wrong. I was used to seeing the person in question on TV, in character, in a fictional show set in Los Angeles, not in real life, in New York, in the company of the mutual acquaintances who had brought me to the party. In the memory of a human being, context is all, and sometimes, as in this instance, context works against us.

Context exerts its powerful effect — sometimes helping us, sometimes not — in part by "priming" the pump of our memory; when I hear the word doctor, it becomes easier to recognize the word nurse. Had someone said "Lauren" (the first name of the actor in question), I probably could have instantly come up with her last name (Ambrose), but without the right cue, I could only draw a blank.

The thing about context is that it is always with us — even when it's not really relevant to what we are trying to remember. Carr's experiment with rats, for instance, has a parallel with humans in a remarkable experiment with scuba divers. The divers were asked to memorize a list of words while underwater. Like the rats that needed electric light to perform well, the scuba divers were better at remembering the words they studied underwater when they were tested underwater (relative to being tested on land) — a fact that strikes this landlubber as truly amazing. Just about every time we remember anything, context looms in the background.*

This is not always a good thing. As Merlin Mann of the blog "43 folders" put it, the time when we tend to notice that we need toilet paper tends not to be the moment when we are in a position to buy it. Relying on context works fine if the circumstance in which we need some bit of information matches the circumstance in which we first stored it — but it becomes problematic when there is a mismatch between the original circumstance in which we've learned something and the context in which we later need to remember it.

Another consequence of contextual memory is the fact that nearly every bit of information that we hear (or see, touch, taste, or smell), like it or not, triggers some further set of memories — often in ways that float beneath our awareness. The novelist Marcel Proust, who coined the term "involuntary memory," got part of the idea — the

* Similarly, if you study while stoned, you might as well take the test while stoned. Or so I have been told.

reminiscences in Proust's famous (and lengthy) novel Remembrance of Things Past were all triggered by a single, consciously recognized combination of taste and smell.