Misremembering Might Actually Be a Sign Your Memory Is Working Optimally

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Yves here. While this piece is a bit of a pep talk for those with less than perfect memory, it’s a little bit bothersome that this article doesn’t distinguish between different aspects of memory. For instance, one friend has freakish recall, particularly of names and faces. It’s only since he turned 55 that he can no longer definitively remember if he ever met someone before….and nearly all the time, he could pull their name, the circumstances, and even how they were dressed a decade plus later. One of my brothers also recalls astonishing amounts of detail from our childhood, although he admits to not always being able to tie them into a narrative. Some people have excellent melodic and rhythm memory, while I couldn’t learn a dance combination to save my life. Yours truly does have a good memory for numbers, but that may be dint of practice (I avoid using a contact list and can generally remember a number I have dialed 2X in a week for at least six months).

In addition, food is too important to me for me to forget a good dessert.

By Robert Jacobs, Professor of Brain and Cognitive Sciences, University of Rochester. Originally published at The Conversation

When asked the other day about a bakery near my home, I responded that I’d recently eaten its mouth-watering chocolate chip cookies. My wife corrected me, noting that the cookies I ate were actually oatmeal raisin.

Why did I make this memory error? Is this an early sign of impending dementia? Should I call my doctor?

Or is forgetting the details of a dessert a good thing, given that everyday life is filled with an enormous number of details, too many for a finite human brain to remember accurately?

I am a cognitive scientist and have been studying human perception and cognition for more than 30 years. My colleagues and I have been developing new theoretical and experimental ways to explore this kind of error. Are these memory mistakes a bad thing, resulting from faulty mental processing? Or, counterintuitively, could they be a good thing, a desirable side effect of a cognitive system with limited capacity working efficiently? We’re leaning toward the latter – that memory errors may actually indicate a way in which the human cognitive system is “optimal” or “rational.”

Are People Rational?

For decades, cognitive scientists have thought about whether human cognition is strictly rational. Starting in the 1960s, psychologists Daniel Kahneman and Amos Tversky conducted pioneering research on this topic. They concluded that people often use “quick and dirty” mental strategies, also known as heuristics.

For example, when asked whether the English language has more words starting with the letter “k” or with “k” as the third letter, most people say there are more words starting with “k.” Kahneman and Tversky argued that people reach this conclusion by quickly thinking of words that start with “k” and with “k” in the third position, and noticing that they can think of more words with that initial “k.” Kahneman and Tversky referred to this strategy as the “availability heuristic” – what comes most easily to mind influences your conclusion.

Although heuristics often yield good results, they sometimes do not. Therefore, Kahneman and Tversky argued that, no, human cognition is not optimal. Indeed, the English language has many more words with “k” in the third position than words starting with “k.”

Suboptimal or the Best It Can Be?

In the 1980s, however, research started appearing in the scientific literature suggesting that human perception and cognition might often be optimal. For instance, several studies found that people combine information from multiple senses – such as vision and hearing, or vision and touch – in a manner that is statistically optimal, despite noise in the sensory signals.

Perhaps most important, research showed that at least some instances of seemingly suboptimal behavior are actually the opposite. For example, it was well known that people sometimes underestimate the speed of a moving object. So scientists hypothesized that human visual motion perception is suboptimal.

But more recent research showed that the statistically optimal sensory interpretation or percept is one that combines visual information about the speed of an object with general knowledge that most objects in the world tend to be stationary or slow moving. Moreover, this optimal interpretation underestimates the speed of an object when visual information is noisy or low quality.

Because the theoretically optimal interpretation and people’s actual interpretation make similar errors in similar circumstances, it may be that these errors are inevitable when visual information is imperfect, and that people are actually perceiving motion speeds as well as they can be perceived.

Scientists found related results when studying human cognition. People often make errors when remembering, reasoning, deciding, planning or acting, especially in situations when information is ambiguous or uncertain. As in the perceptual example on visual speed estimation, the statistically optimal strategy when performing cognitive tasks is to combine information from data, such as things one has observed or experienced, with general knowledge about how the world typically works. Researchers found that the errors made by optimal strategies – inevitable errors due to ambiguity and uncertainty – resemble the errors people really make, suggesting that people may be performing cognitive tasks as well as they can be performed.

Evidence has been mounting that errors are inevitable when perceiving and reasoning with ambiguous inputs and uncertain information. If so, then errors are not necessarily indicators of faulty mental processing. In fact, people’s perceptual and cognitive systems may actually be working quite well.

Your Brain, Under Constraints

There are often constraints on human mental behavior. Some constraints are internal: People have limited capacity for paying attention – you can’t attend to everything simultaneously. And people have limited memory capacity – you can’t remember everything in full detail. Other constraints are external, such as the need to decide and act in a timely manner. Given these constraints, it may be that people cannot always perform optimal perception or cognition.

But – and this is the key point – although your perception and cognition might not be as good as they could be if there were no constraints, they might be as good as they could be given the presence of these constraints.

Consider a problem whose solution requires you to think simultaneously about many factors. If, because of capacity limits on attention, you cannot think about all factors at once, then you will not be able to think of the optimal solution. But if you think about as many factors as you can hold in your mind at the same time, and if these are the most informative factors for the problem, then you’ll be able to think of a solution that is as good as possible given your limited attention.

The Limits of Memory

This approach, emphasizing “constrained optimality,” is sometimes known as the “resource-rational” approach. My colleagues and I have developed a resource-rational approach to human memory. Our framework thinks of memory as a type of communication channel.

When you place an item in memory, it’s as if you’re sending a message to your future self. However, this channel has limited capacity, and thus it cannot transmit all details of a message. Consequently, a message retrieved from memory at a later time may not be the same as the message placed into memory at the earlier time. That is why memory errors occur.

If your memory store cannot faithfully maintain all details of stored items because of its limited capacity, then it would be wise to make sure that whatever details it can maintain are the important ones. That is, memory should be the best it can be within limited circumstances.

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Indeed, researchers have found that people tend to remember task-relevant details and to forget task-irrelevant details. In addition, people tend to remember the general gist of an item placed in memory, while forgetting its fine details. When this occurs, people tend to mentally “fill in” the missing details with the most frequent or commonplace properties. In a sense, the use of commonplace properties when details are missing is a type of heuristic – it is a quick-and-dirty strategy that will often work well but sometimes fail.

Why did I recall eating chocolate chip cookies when, in fact, I had eaten oatmeal raisin cookies? Because I remembered the gist of my experience – eating cookies – but I forgot the fine details, and thus filled in these details with the most common properties, namely cookies with chocolate chips. In other words, this error demonstrates that my memory is working as well as possible under its constraints. And that’s a good thing.

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  1. BeliTsari

    Funny, to be experiencing PASC brain-fog & memory holes right as it’s panoply of seemingly random effects includes: names and faces, taste & scent, short-term memory, along with childhood brain-storm images, coming back to haunt as a geezer? Cognition, mindfulness and most especially ANY consensus reality based deja-vu flash-backs are likely to trigger cognitive dissonance just now?



  2. Louis Fyne

    Things are easier to remember by musical-rhymic mnemoics or when fused into a mental image like “King Paul Cried Out For Some Good Soup” or “the Mitosis song.” The brain creates more connections via imagery which makes possible easier recall later versus trying to remember an abstract list of words.

    Supported both by clinical data and real-life examples—people memersizing hundreds of pages of text, Turkish bards singing the Iliad to song or reciting Vedic texts, or people using the those techniques to try to win competitve memory games. https://www.worldmemorychampionships.com/

    1. Laughingsong

      This is what I experience although not as exactly. I always joke about being in an old folks home in a few years, gumming my food and not knowing who or where I am but still able to sing entire Pink Floyd albums from start to finish…

      “ The memories of a man in his old age are the deeds of a man in his prime….”

      1. Duke of Prunes

        Except I usually only remember the words for most songs when I hear the music (or can hear the music in my head).

      2. Eustachedesaintpierre

        Reminds me a touching video I once watched featuring an old black guy with some form of dementia, who was given an mp3 player which basically lit him up. I need a prompt from the song to be able to howl to it & from when I was young I always had a problem remembering people’s names.

        The strangest memory prompt I ever had was in Kew Botanical Gardens as I walked along feeling the leaves of different plants – suddenly I was 5 years old in the backyard of the house we lived in on the outskirts of Nairobi, The plant was a banana tree whose branches had hung over the back wall which we kids would jump up to grab.

        Now I consider myself as absent minded, but she prefers dozy prick.

  3. The Rev Kev

    I suppose that it is a bridge too far to say why are we just depending on how good people’s natural memories are when memory training could be taught from a young age in school. After all, when a kid in school plays a sport, nobody says that we will just depend on that kid’s natural talent to be able to play that game and go with that. A lot of time and effort is spent in training kids to play a sport. So why not with memory training too?

    1. JBird4049

      Memory training was often taught in school. It just with the easy availability of paper and the skill of writing that was let go. The people of the Middle Ages especially the educated would laugh at our memory skills now.

  4. Carolinian

    In the important scientific papers known as the Sherlock Holmes stories (hey, they were written by a doctor) Sherlock says that your brain is like an attic and when you haul one thing up the attic stairs something else gets shoved out the attic window.

    I think this is true although the defenestrated thing is still up there somewhere which is how we can have flashes of memory regarding events that happened many years ago but not what we had for that lunch that was so routine and boring.

  5. lordkoos

    As a musician I can recall how to play songs I played 40 years ago better than I can remember where I left my cell phone. Speaking of cell phones, using one has destroyed my ability to remember phone numbers. The only number I can reliably remember is my mother’s as she’s had the same number for 60 years.

  6. Susan the other

    Lately I’ve had memory blocks. A few where I don’t have any memory whatsoever of something I know I know. One question is how do I know I know? I can only compare it to a back injury I had cross-country skiing – I took a really bad fall and it damaged some nerves in my back which caused one side of my lower back to go completely numb for several months. Gradually my nerves grew back. (Don’t forget to take your B complex!) So I’d just posit that the same thing can happen to memory – if you get a total loss of some detail, some atrophy of your synapses, keep poking it. It will grow back. I can usually remember everything (as far as I know) but sometimes the memory is so close to gone that I have to be patient to retrieve it. This is kind of what the author is saying here – that memory is retrievable even if the clues are imperfect. It’s remarkable that you can retrieve it and usually, for me, it’s a veritable movie.

  7. skk

    Sometimes I just cannot recall certain names that I ought to never forget – e.g. recently I couldn’t recall the name Stevie Nicks as a member of Fleetwood Mac. I could picture her face, her voice, some songs but not the name. I could recall the other members names just not hers. I had to google it in the end !
    Which is what I blame this type of forgetfulness on. I can look up so many things so easily online that I no longer put the effort in to remember things – I was taught the association method for memorizing things at that.
    The other thing I blame it on is the sheer number of things in my life. Using the old computing storage model, once you run of space in RAM memory, to add things you have to send less used items off to disk, and when that’s full, to tape. Then when it comes to retrieving an item that hasn’t been accessed for a while, it has to come back from tape –>drive–>RAM which takes a while.

    Nowadays of course you just add a disk ! sadly one can’t seem to do that in a human brain, yet anyway.

  8. Cat Burglar

    Playing for time is the way I handle every complex decision, especially as I get older. It takes time to sift through all the factors, and not always consciously.

    Recently I was prescribed antibiotics for a medical procedure, and duly noted their names. A couple weeks later, I woke up in the middle of the night with one thought: Sadie Bjornsen! The great nordic ski racer had retired from the World Cup racing circuit, and, months before, I had read an interview with her about her career. Amazingly,she had become a great skier, despite being only able to work out for 30 minutes at a time, and being constantly plagued by connective tissue problems. The reason was an antibiotic she had taken for a sinus infection as a teenager, that had a side-effect of causing tendon ruptures. I had awakened without recalling the name, but had a strong feeling of recognition. I got out of bed, fired up the computer and found the name: the very one I had been prescribed. Time to call the doctor.

  9. Christian J. Chuba

    I’ve always been fascinated by delayed recollection.
    This is when I remember an experience but cannot recall an important detail such as, ‘what was the name of that [movie, person, tool that I used]’. It bothers me but I give up. Then an hour or even a day later, I recall it while doing something else, ‘apricot!’ it was ‘apricot!’. It’s as if my mind was doing a background search through its archives.

    I can’t be the only person this happens to, am I? I don’t know if this is universal or if it’s tied to a personality type such as obsessive compulsive. I do get a sense of relief when I finally get the answer.

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