Farnam Street helps you make better decisions, innovate, and avoid stupidity.

With over 350,000 monthly readers and more than 87,000 subscribers to our popular weekly digest, we've become an online intellectual hub.

The Many Ways Our Memory Fails Us (Part 2)

(Purchase a copy of the entire 3-part series in one sexy PDF for $3.99)

***

In part one, we began a conversation about the trappings of the human memory, using Daniel Schacter’s excellent The Seven Sins of Memory as our guide. We covered transience — the loss of memory due to time — and absent-mindedness — memories that were never encoded at all or were not available when needed. Let’s keep going with a couple more whoppers: Blocking and Misattribution.

Blocking

Blocking is the phenomenon when something is indeed encoded in our memory and should be easily available in the given situation, but simply will not come to mind. We’re most familiar with blocking as the always frustrating “It’s on the tip of my tongue!

Unsurprisingly, blocking occurs most frequently when it comes to peoples’ names and occurs more frequently as we get older:

Twenty-year-olds, forty-year-olds, and seventy-year-olds kept diaries for a month in which they recorded spontaneously occurring retrieval blocks that were accompanied by the “tip of the tongue” sensation. Blocking occurred occasionally for the names of objects (for example, algae) and abstract words (for example, idiomatic). In all three groups, however, blocking occurred most frequently for proper names, with more blocks for people than for other proper names such as countries or cities. Proper name blocks occurred more frequently in the seventy-year-olds than in either of the other two groups.

This is not the worst sin our memory commits — excepting the times when we forget an important person’s name (which is admittedly not fun), blocking doesn’t cause the terrible practical results some of the other memory issues cause. But the reason blocking occurs does tells us something interesting about memory, something we intuitively know from other domains: We have a hard time learning things by rote or by force. We prefer associations and connections to form strong, lasting, easily available memories.

Why are names blocked from us so frequently, even more than objects, places, descriptions, and other nouns? For example, Schacter mentions experiments in which researchers show that we more easily forget a man’s name than his occupationeven if they’re the same word! (Baker/baker or Potter/potter, for example.)

It’s because relative to a descriptive noun like “baker,” which calls to mind all sorts of connotations, images, and associations, a person’s name has very little attached to it. We have no easy associations to make — it doesn’t tell us anything about the person or give us much to hang our hat on. It doesn’t really help us form an image or impression. And so we basically remember it by rote, which doesn’t always work that well.

Most models of name retrieval hold that activation of phonological representations [sound associations] occurs only after activation of conceptual and visual representations. This idea explains why people can often retrieve conceptual information about an object or person whom they cannot name, whereas the reverse does not occur. For example, diary studies indicate that people frequently recall a person’s occupation without remembering his name, but no instances have been documented in which a name is recalled without any conceptual knowledge about the person. In experiments in which people named pictures of famous individuals, participants who failed to retrieve the name “Charlton Heston” could often recall that he was an actor. Thus, when you block on the name “John Baker” you may very well recall that he is an attorney who enjoys golf, but it is highly unlikely that you would recall Baker’s name and fail to recall any of his personal attributes.

A person’s name is the weakest piece of information we have about them in our people-information lexicon, and thus the least available at any time, and the most susceptible to not being available as needed. It gets worse if it’s a name we haven’t needed to recall frequently or recently, as we all can probably attest to. (This also applies to the other types of words we block on less frequently — objects, places, etc.)

The only real way to avoid blocking problems is to create stronger associations when we learn names, or even re-encode names we already know by increasing their salience with a vivid image, even a silly one. (If you ever meet anyone named Baker…you know what to do.)

But the most important idea here is that information gains salience in our brain based on what it brings to mind. 

Whether or not blocking occurs in the sense implied by Freud’s idea of repressed memories, Schacter is non-committal about — it seems the issue was not, at the time of writing, settled.

Misattribution

The memory sin of misattribution has fairly serious consequences. Misattribution happens all the time and is a peculiar memory sin where we do remember something, but that thing is wrong, or possibly not even our own memory at all:

Sometimes we remember events that never happened, misattributing speedy processing of incoming information or vivid images that spring to mind, to memories of past events that did not occur. Sometimes we recall correctly what happened, but misattribute it to the wrong time and place. And at other times misattribution operates in a different direction: we mistakenly credit a spontaneous image or thought to our own imagination, when in reality we are recalling it–without awareness–from something we read or heard.

The most familiar, but benign, experience we’ve all had with misattribution is the curious case of deja vu. As of the writing of his book, Schacter felt there was no convincing explanation for why deja vu occurs, but we know that the brain is capable of thinking it’s recalling an event that happened previously, even if it hasn’t.

In the case of deja vu, it’s simply a bit of an annoyance. But the misattribution problem causes more serious problems elsewhere.

The major one is eyewitness testimony, which we now know is notoriously unreliable. It turns out that when eyewitnesses claim they “know what they saw!” it’s unlikely they remember as well as they claim. It’s not their fault and it’s not a lie — you do think you recall the details of a situation perfectly well. But your brain is tricking you, just like deja vu. How bad is the eyewitness testimony problem? It used to be pretty bad.

…consider two facts. First, according to estimates made in the late 1980s, each year in the United States more than seventy-five thousand criminal trials were decided on the basis of eyewitness testimony. Second, a recent analysis of forty cases in which DNA evidence established the innocence of wrongly imprisoned individuals revealed that thirty-six of them (90 percent) involved mistaken eyewitness identification. There are no doubt other such mistakes that have not been rectified.

What happens is that, in any situation where our memory stores away information, it doesn’t have the horsepower to do it with complete accuracy. There are just too many variables to sort through. So we remember the general aspects of what happened, and we remember some details, depending on how salient they were.

We recall that we met John, Jim, and Todd, who were all part of the sales team for John Deere. We might recall that John was the young one with glasses, Jim was the older bald one, and Todd talked the most. We might remember specific moments or details of the conversation which stuck out.

But we don’t get it all perfectly, and if it was an unmemorable meeting, with the transience of time, we start to lose the details. The combination of the specifics and the details is a process called memory binding, and it’s often the source of misattribution errors.

Let’s say we remember for sure that we curled our hair this morning. All of our usual cues tell us that we did — our hair is curly, it’s part of our morning routine, we remember thinking it needed to be done, etc. But…did we turn the curling iron off? We remember that we did, but is that yesterday’s memory or today’s?

This is a memory binding error. Our brain didn’t sufficiently “link up” the curling event and the turning off of the curler, so we’re left to wonder. This binding issue leads to other errors, like the memory conjunction error, where sometimes the binding process does occur, but it makes a mistake. We misattribute the strong familiarity:

Having met Mr. Wilson and Mr. Albert during your business meeting, you reply confidently the next day when an associate asks you the name of the company vice president: “Mr. Wilbert.” You remembered correctly pieces of the two surnames but mistakenly combined them into a new one. Cognitive psychologists have developed experimental procedures in which people exhibit precisely these kinds of erroneous conjunctions between features of different words, pictures, sentences, or even faces. Thus, having studied spaniel and varnish, people sometimes claim to remember Spanish.

What’s happening is a misattribution. We know we saw the syllables Span- and –nish and our memory tells us we must have heard Spanish. But we didn’t.

Back to the eyewitness testimony problem, what’s happening is we’re combining a general familiarity with a lack of specific recall, and our brain is recombining those into a misattribution. We recall a tall-ish man with some sort of facial hair, and then we’re shown 6 men in a lineup, and one is tall-ish with facial hair, and our brain tells us that must be the guy. We’re make a relative judgment: Which person here is closest to what I think I saw? Unfortunately, like the Spanish/varnish issue, we never actually saw the person we’ve identified as the perp.

None of this occurs with much conscious involvement, of course. It’s happening subconsciously, which is why good procedures are needed to overcome the problem. In the case of suspect lineups, the solution is to show the witness each member, one after another, and have them give a thumbs up or thumbs down immediately. This takes away the relative comparison and makes us consciously compare the suspect in front of us with our memory of the perpetrator.

The good thing about this solving this error is that people can be encouraged to search their memory more carefully. But it’s far from foolproof, even if we’re getting a very strong indication that we remember something.

And what helps prevent us from making too many errors is something Schacter calls the distinctiveness heuristic. If a distinctive thing supposedly happened, we usually reason we’d have a good memory of it. And usually, this is a very good heuristic to have. (Remember, salience always encourages memory formation.) As we discussed in Part One, a salient artifact gives us something to tie a memory to. If I meet someone wearing a bright rainbow-colored shirt, I’m a lot more likely to recall some details about them, simply because they stuck out.

***

As an aside, misattribution allows us one other interesting insight into the human brain: Our “people information” remembering is a specific, distinct module, one that can falter on its own, without harming any other modules. Schacter discusses a man with a delusion that many of the normal people around him were film stars. He even misattributed made-up famous-sounding names (like Sharon Sugar) to famous people, although he couldn’t put his finger on who they were.

But the man did not falsely recognize other things. Made up cities or made up words did not trip up his brain in the strange way people did. This (and other data) tells us that our ability to recognize people is a distinct “module” our brain uses, supporting one of Judith Rich Harris’s modules of human personality that we’ve discussed: The “people information lexicon” we develop throughout our lives.

***

One final misattribution is something called cryptomnesia — the opposite of deja vu. It’s when we think we recognize something as new and novel when we have indeed seen it before. Accidental plagiarizing can even result from cryptomnesia. (Try telling that to your school teachers!) Cryptomnesia falls into the same bucket as other misattributions in that we fail to recollect the source of information we’re recalling — the information and event where we first remembered it are not bound together properly. Let’s say we “invent” the melody to a song which already exists. The melody sounds wonderful and familiar, so we like it. But we mistakenly think it’s new.

In the end, Schacter reminds us to think carefully about the memories we “know” are true, and to try to remember specifics when possible:

We often need to sort out ambiguous signals, such as feelings of familiarity or fleeting images, that may originate in specific past experiences, or arise from subtle influences in the present. Relying on judgment and reasoning to come up with plausible attributions, we sometimes go astray.  When misattribution combines with another of memory’s sins — suggestibility — people can develop detailed and strongly held recollections of complex events that never occurred.

And with that, we will leave it here for now. Next time we’ll delve into suggestibility and bias, two more memory sins with a range of practical outcomes.