Category: Memory

Recently the neurologist and author Oliver Sacks recalled a vivid childhood memory, recounted in his autobiography, Uncle Tungsten.

During WWII he lived in London during the Blitz, and on one occasion:

“…an incendiary bomb, a thermite bomb, fell behind our house and burned with a terrible, white-hot heat. My father had a stirrup pump, and my brothers carried pails of water to him, but water seemed useless against this infernal fire—indeed, made it burn even more furiously. There was a vicious hissing and sputtering when the water hit the white-hot metal, and meanwhile the bomb was melting its own casing and throwing blobs and jets of molten metal in all directions.”

Except when his autobiography came out, one of his older brothers told him he’d misremembered the event. In fact both of them had been at school when the bomb struck so they could not have witnessed the explosion.

The ‘false’ memory, it turned out, was implanted by a letter. Their elder brother had written to them, describing the frightening event, and this had lodged in his mind. Over the years the letter had gone from a third-person report to a first-person ‘memory’.

Turning the memory over in his mind, Sacks writes that he still cannot see how the memory of the bomb exploding can be false. There is no difference between this memory and others he knows to be true; it felt like he was really there.

***

This sort of experience is probably much more common than we might like to imagine. Many memories which have the scent of authenticity may turn out to be misremembered, if not totally fictitious events, if only we could check. Without some other source with which to corroborate, it is hard verify the facts, especially for events that took place long ago.

That these sorts of distortions to memory happen is unquestioned, what fascinates is how it comes about. Does the long passage of time warp the memory, or is there some more active process that causes the change?

A study published recently sheds some light on this process and provides a model for how memories like Sack’s become distorted.

In the experiment participants took part in a self-guided museum tour where they were told to stop at particular exhibits along the way (St. Jacques & Schacter, 2013). These stops on the museum tour are the experimental stand-ins for the events you’ve experienced across your life.

Participants were asked to look at a series of photos showing the stops they visited during their tour, a sort of ‘event-movie’, thus retrieving or reactivating memory. Following retrieval, they were shown a new photo taken at the museum that showed stops that were not part of their tour.

This is something like what goes on when you sit looking out of the window on a wet Sunday afternoon, thinking back to childhood memories. Images come back to you in no particular order: some of which may be true memories, others things you’ve been told or simply fabricated. They are jumbled; the sources unclear and the meanings opaque.

In the study participants returned for a third session and were shown photos and asked whether they’d stopped at the exhibit or not. Once again, some of the time they were shown pairs of exhibits they had or hadn’t looked at and other times real and false memories were mixed up together.

Across the three sessions, then, the researchers had simulated the recall of the jumble of real and false memories that are likely to be returned to consciousness when we try to recall past events. Real aspects of a memory get mixed up with false aspects and the whole confection gets stirred up each time we recall it.

In the study they found that participants’ memories were both enhanced and distorted by the process of recall. People found it easier to remember those exhibits which they were subsequently shown photographs of. This shows that merely recalling a memory is enough to strengthen it.

This is one aspect of the fact that memory is an active, reconstructive process; recalling something is not a neutral act, it strengthens that memory in comparison to the others.

But the study also demonstrated that false memories were also strengthened. In other words when participants falsely recalled seeing a particular exhibit in the second session, this made it more likely to be flagged up as a ‘real’ memory in the third session.

What this is showing is how false memories can grow in the mind. Of course, in real life things don’t happen as cleanly as they do in the psych lab. Our memories and fantasies are intertwined, crossing over and interfering with one another. Thinking about the past continues this process of interweaving.

Something like this may have happened to Sacks. Indeed, while he didn’t actually witness the bomb blast described above, he had been there at an earlier incident, describing it thus:

“One night, a thousand-pound bomb fell into the garden next to ours, but fortunately it failed to explode. All of us, the entire street, it seemed, crept away that night (my family to a cousin’s flat)—many of us in our pajamas—walking as softly as we could (might vibration set the thing off?). The streets were pitch dark, for the blackout was in force, and we all carried electric torches dimmed with red crêpe paper. We had no idea if our houses would still be standing in the morning.”

His brother confirmed that he had been there that time.

***

Anyone who thinks that the main aim of memory is fidelity will find this study disheartening. It seems to underline the fragile nature of memory and the human mind in general.

But there is a way to look at it that is not only more positive, but also hints at ways to make valuable personal changes.

What emerges is that autobiographical memory is not just about accurately remembering what happened when, it is an active construction of the self. How you think about the past helps generate your experience in the moment as well as the decisions you take in the future.

If that autobiographical memory can change based on how you recall the past, then our pasts are not gone and forgotten, they are living parts of who we are. Choosing to recall certain events rather than others is a way of choosing how we live now and what decisions we make in the future.

What’s done may be done, but it’s still open to reinterpretation.

Image credit: Joel-Evelyn-Francois

I have a great memory for books I’ve read on trains.

I always thought this had something to do with the nature of train travel: the rocking of the carriage, the rhythm of the stops, the continually changing picture window. Perhaps the combination of all these helps induce a focus which is harder to achieve in familiar circumstances.

Or perhaps the answer is simpler.

Psychologists have found that brief resting periods after learning aids memory. In studies, when people take a little rest after learning, say, a string of numbers, they do better in recall than other people who’ve been given another task straight away.

It is thought that this little rest helps consolidate the memory, making it easier to retrieve. On the other hand if you go straight on to another task, the memory doesn’t have a chance to solidify.

I began to wonder if this suggested why I find it easier to recall books I’ve read on trains.

Unlike at home where I read continuously, on a train I tend to stop more frequently to look out of the window or see who is getting on at the next stop. These would be exactly the type of restful periods described in this research.

The problem is these findings have only been shown over very short periods. That is until now.

10-minute break

In a new study the effect of a 10-minute break was tested on participants’ recall of a story 7 days later (Dewar et al., 2012).

They found that even after 7 days people’s memory was enhanced when they took a 10-minute break after reading the story. In fact, 7 days later people who’d taken a break were as good as those trying to recall the story just 15-30 minutes later, but without the break.

So perhaps this helps explain why I have a clearer memory of books I’ve read on trains.

It also shows that one of the pleasures of reading—pausing to let it wash over you—is not only agreeable but also helps you remember what you’ve read.

Image credit: Jens Schott Knudsen

Committing words to memory is a notoriously hit-and-miss business. Over the last forty years psychologists have found three methods which consistently improve memory for words:

1. Imagery: recall is aided by creating an image of what you want to remember.
2. Elaboration: thinking of associations helps anchor words in your mind.
3. Generation: memory is improved when you have to put some work in to generate the target. E.g. guess the name of your favourite blog from this cryptic clue: _sy_log.

In research on trying to remember lists of words, these three methods have each produced memory improvements of 10% over simply reading words once.

That might not sound much, but it is an average over many studies and often for things that are hard to remember. Psychologists like testing people with non-words like ‘trackle’ or ‘nosting’ that could be words, but aren’t.

Speak it…

Now, in a new series of studies published in the Journal of Experimental Psychology: Learning, Memory, and Cognition, there’s solid evidence for a fourth which could join the other big three memory enhancers (MacLeod et al., 2010).

And, you’ll be happy to hear, it’s very, very simple. It only involves saying the word you want to remember out loud to yourself. It doesn’t even seem to matter if you don’t vocalise the word, it only has to be mouthed. That’s it.

According to MacLeod et al., saying a word out loud, or at least mouthing it, improves memory by increasing its distinctiveness, i.e. making it unusual compared to others.

Across 8 experiments in which participants were asked to read and remember lists of both words and nonwords, the researchers found memory improvements sometimes greater than 10%. They also ruled out some alternative explanations, finding that improvements were not:

• At the expense of unmouthed words. The effect was all benefit for the mouthed words and didn’t decrease performance on unmouthed words.
• A result of “lazy reading” of words read silently.

…but be selective

Of course just reading all the words out loud would destroy the effect because then there’s nothing for words said out loud to be distinctive in comparison with. It’s only going to work when some words are said out loud compared with others not.

So if you’re revising, or reading a report or a book and want to retain more of the important points, the key is to identify the right words and vocalise or sub-vocalise them.

This finding ties in with the general idea that we tend to remember people or things that stand out from the crowd. One gentle reminder though: if you are spotted mouthing random words in public, it’s you that will stand out from the crowd.

→ Continue reading: Memory and Recall: 10 Amazing Facts You Should Know

Image credit: Florian Seroussi