flickering pictures

Ever been in the awkward situation of bumping into an old acquaintance, only to realize that you’ve completely forgotten his or her name? Their name is on the tip of your tongue, but you can’t produce it for the life of you. The Boston Globe explains why:

[…] For the last several decades, scientists have assumed that the brain contains some innate indexing system, akin to a card catalog in a library, that allows it to immediately realize that it can produce a specific piece of knowledge. This is known as the “direct access” model, since it implies that the conscious brain has direct access to the vast contents of the unconscious.

The tip-of-the-tongue experience, however, is leading researchers to question this straightforward model. According to this new theory, the brain doesn’t have firsthand access to its own memories. Instead, it makes guesses based upon the other information that it can recall. For instance, if we can remember the first letter of someone’s name, then the conscious brain assumes that we must also know his or her name, even if we can’t recall it right away. This helps explain why people are much more likely to experience a tip-of-the-tongue state when they can recall more information about the word or name they can’t actually remember.

Most people think of the brain as a sort of supercomputer that receives a request for information and then zips over to just the right databank for the appropriate tidbit. This theory suggests that the brain is more of a bleary-eyed librarian, with just a vague notion of what books are in his library and only a general idea of where to find them. This is your brain deciding to look “somewhere over there” for the data you want.

But it gets even weirder:

[…] According to Schacter, the tip-of-the-tongue moment demonstrates a peculiar aspect of memory, which is that different aspects of memory are stored separately in the brain. When we think about a friend, all of our memories of that friend aren’t filed away in a single location. Instead, different aspects of the memory are distributed throughout the brain, so that a proper name is separated from a visual memory of a face.

“When we remember something, that memory feels unified,” Schacter says. “But the reality is that you assemble each memory out of lots of different pieces. A tip-of-the-tongue state occurs when one of the pieces gets lost.”

The amazing thing — at least to me — is that somehow this actually works. Against all odds to the contrary, the brain’s scattered filing system is still good enough to come up with nearly all the information we search for, even though the “system” is incredibly chaotic and thinking about one childhood toy might trigger dozens of thoughts, memories and feelings stored individually in many, many sectors of the brain.

It’s all the more impressive when you consider the enormous volume of data we store in there — everything from how to drive to our social security numbers to the facial features of our fourth-grade teacher — and how quickly we can come up with it. One split-second thought, and there’s Mrs. Morrison again, going on about grammar at the front of the class just like she did decades ago.

Brain image via the Visual Dictionary.
Finger image via the Bedin and Narvik.

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