I Am a Strange Loop

Consider the mundane-seeming concept of “grocery store checkout stand”, which I would be willing to bet is a member in good standing of your personal conceptual repertoire. It already sounds like a nested entity, being compounded from four words; thus it tells us straightforwardly that it symbolizes a stand for checking out in a store that deals in groceries. But looking at its visible lexical structure barely scratches the surface. In truth, this concept involves dozens and dozens of other concepts, among which are the following: “grocery cart”, “line”, “customers”, “to wait”, “candy rack”, “candy bar”, “tabloid newspaper”, “movie stars”, “trashy headlines”, “sordid scandals”, “weekly TV schedule”, “soap opera”, “teenager”, “apron”, “nametag”, “cashier”, “mindless greeting”, “cash register”, “keyboard”, “prices”, “numbers”, “addition”, “scanner”, “bar code”, “beep”, “laser”, “moving belt”, “frozen food”, “tin can”, “vegetable bag”, “weight”, “scale”, “discount coupon”, “rubber separator bar”, “to slide”, “bagger”, “plastic bag”, “paper bag”, “plastic money”, “paper money”, “to load”, “to pay”, “credit card”, “debit card”, “to swipe”, “receipt”, “ballpoint pen”, “to sign”, and on and on. The list starts to seem endless, and yet we are merely talking about the internal richness of one extremely ordinary human concept.

Not all of these component concepts need be activated when we think about a grocery store checkout stand, to be sure — there is a central nucleus of concepts all of which are reliably activated, while many of these more peripheral components may not be activated — but all of the foregoing, and considerably more, is what constitutes the full concept in our minds. Moreover, this concept, like every other one in our minds, is perfectly capable of being incorporated inside other concepts, such as “grocery store checkout stand romance” or “toy grocery store checkout stand”. You can invent your own variations on the theme.

Episodic Memory

When we sit around a table and shoot the breeze with friends, we are inevitably reminded of episodes that happened to us some time back, often many years ago. The time our dog got lost in the neighborhood. The time our neighbor’s kid got lost in the airport. The time we missed a plane by a hair. The time we made it onto the train but our friend missed it by a hair. The time it was sweltering hot in the train and we had to stand up in the corridor all the way for four hours. The time we got onto the wrong train and couldn’t get off for an hour and a half. The time when nobody could speak a word of English except “Ma-ree-leen Mon-roe!”, spoken with lurid grinning gestures tracing out an hourglass figure in the air. The time when we got utterly lost driving in rural Slovenia at midnight and were nearly out of gas and yet somehow managed to find our way to the Italian border using a handful of words of pidgin Slovenian. And on and on.

Episodes are concepts of a sort, but they take place over time and each one is presumably one-of-a-kind, a bit like a proper noun but lacking a name, and linked to a particular moment in time. Although each one is “unique”, episodes also fall into their own categories, as the previous paragraph, with its winking “You know what I mean!” tone, suggests. (Missing a plane by a hair is not unique, and even if it has happened to you only once in your life, you most likely know of several members of this category, and can easily imagine an unlimited number of others.)

Episodic memory is our private storehouse of episodes that have happened to us and to our friends and to characters in novels we’ve read and movies we’ve seen and newspaper stories and TV news clips, and so on, and it forms a major component of the long-term memory that makes us so human. Obviously, memories of episodes can be triggered by external events that we witness or by other episodes that have been triggered, and equally obviously, nearly all memories of specific episodes are dormant almost all the time (otherwise we would go stark-raving mad).

Do dogs or cats have episodic memories? Do they remember specific events that happened years or months ago, or just yesterday, or even ten minutes ago? When I take our dog Ollie running, does he recall how he strained at the leash the day before, trying to get to say “hi” to that cute Dalmatian across the street (who also was tugging at her leash)? Does he remember how we took a different route from the usual one three days ago? When I take Ollie to the kennel to board over Thanksgiving vacation, he seems to remember the kennel as a place, but does he remember anything specific that happened there the last time (or any time) he was there? If a dog is frightened of a particular place, does it recall a specific trauma that took place there, or is there just a generalized sense of badness associated with that place?