Dream Weaver: why can’t you get me through the night? The science behind remembering our dreams (or not).

By Christine Jasoni 26/02/2014 6

OMG – you were in my dream last night! This may be good or bad, surprising or disturbing, but most of us have had dreams with bizarre circumstances or the appearance of unusual characters, like your boss or your mother-in-law. But for many of us there is little recollection of anything else. Sometimes we can remember a few details of our dreams when we first wake-up. This especially happens when the thing that wakes us up (like the ringing phone) is actually part of what’s going on in our dream. But even that information tends to fade as the day goes on. Recently, a friend at work was vividly recalling a dream that she’d had the night before, and I must admit that I had a hard time believing that she could actually remember so much. I investigated this a bit further and, as it turns out, many people can recall their dreams quite vividly. So, why can’t I?

In the middle of last year Neuroscientists figured out that people who can frequently recall their dreams wake up at night nearly twice as often as people who rarely recall their dreams. One reason why these high dream recallers wake up more often, at least partly, is because they also are more sensitive to sounds, and thus more likely to be awakened by them [1]. This makes sense, since once awake there is the opportunity to consciously remember the dream. This made me wonder: on the rare occasions when I do remember my dreams, is it because I had a poor night’s sleep? Or might there be something fundamentally different between my brain and the brains of people who remember their dreams regularly?

There was another interesting finding in this study showing differences between high and low dream recallers, but it is complicated and difficult to see how it relates directly to dreams. But here goes… As it turns out, people who recall their dreams (the same ones who awaken more easily to sounds in general) also respond more strongly to the sound of their own name when they are awake. In this study, participants were divided into high dream recallers and low dream recallers, and they were played music which had someone speaking their name in the middle of the music. The brains of the high dream recallers showed very high responses to the sound of their name, compared to the brains of people who don’t remember their dreams. The researchers argue that this is an indication that there are fundamental differences in the way that the brain responds to sounds in the two groups of people. OK. I can buy that, but they didn’t actually link this to dreams and sleeping. In fact, when the same scenario was repeated but to people who were asleep, there was no difference in the responses of anyone’s brain to the sound of their name. At this point we’re left with a curious observation that high and low dream recallers have differences in brain activity and responsiveness when they are awake. But what’s that got to do with dreaming?

More recently, researchers have tried to answer this question by using brain scanning technology called positron emission tomography (PET), which essentially allows scientists to monitor activity in the brain, in real-time, in people who are awake or asleep [2]. The researchers found that two regions of the brain, the temporo-parietal junction and the medial prefrontal cortex, were more active in high dream recallers, awake or asleep, than in people like me. I found this much more interesting, because these brain differences better explain the differences in dreaming and sleeping between the two groups. This also supports the previous study, suggesting that low dream recallers like me really may be different from high dream recallers in some of our awake behaviours too. Just what these behavioural differences might be are still unclear. An even more interesting question is: what about people who used to remember their dreams, but now they don’t or vice versa. This research suggests that their brains have changed, and that the brain changes could affect their awake behaviours too.

To me, that’s really interesting to think about. We know that our environment can lead to changes in our behaviours because of changes in our brain structure and function. This is the basis of learning and memory. Actual structural changes in our brain happen when we remember things that we’ve learned, such as multiplication tables, the route to work, or not to touch the hot stove. And in experiments where the brain changes were blocked from happening, individuals were no longer able to retain memories of what they learned. What we don’t know is whether the brain function that gives rise to the awake behaviour influences the dream remembering, or whether the dream remembering brain function brings about certain awake behaviours. It’s a bit of a chicken-and-egg problem. So if we think about who used to remember their dreams, but don’t any more, here’s the question: might they have had some experience that caused their awake behaviours to change (new work environment, changes in life or lifestyle), and that the brain changes that happened to support this awake behaviour change this also resulted in changes to their brains’ ability to remember dreams? It’s a tough problem to get your head around and think about, but fascinating to consider the possibilities.

But there is a completely other way of looking at how brain activity relates to dream recall. What if people who recall their dreams actually dream more, so that they just have a greater chance of remembering something? If this were the case then the differences in brain activity might relate to differences in the ability to form dreams rather than to recall them. This could have an influence on awake behavoiur in some unknown way; perhaps people with lots of dreams have more active brains when awake as well, and are thus more sensitive to their name and other sounds. This must await further research. I hope you can see that even in just this one small aspect of what our brains can do there is enormous room for further research and understanding; understanding that will enlighten us as individuals into what makes us “tick”, but also in the realm of assisting people with mental illnesses in which their brains respond unusually to their environment. In the meantime I am content to be a low dream recaller because I am able to enjoy a good night’s sleep undisturbed by creepy images of my mother-in-law carrying automatic weapons whilst in the loving arms of Rasputin. Do enjoy your evening ahead.


6 Responses to “Dream Weaver: why can’t you get me through the night? The science behind remembering our dreams (or not).”

  • Ok, so; what about if you have a really common name, and have grown used to ignoring it when you hear it? I only very rarely remember my dreams, sleep very deeply – and have one of the most common names of my generation (Sarah). A link! Hah.

    Fundamental difference, or learned? And further to your observations re. work, stress etc effecting sleeping patterns; if you’re in a new job or environment where you have to be more alert (eg a production line in a busy/dangerous factory, as opposed to sitting at a desk in a quiet office) does your sleeping pattern change?

    • Thanks for reading. These are all really good points. I think if I might give a generic answer (not intended as a cop-out necessarily), it’s that we really don’t know for sure. There may very will be instances of brain function changing as a consequence of all of the things you mention, and then secondarily having this affect other systems. It’s a bit like selection (natural or artificial via breeding) of traits, where some are actively selected for or against and others just come along for the ride. In genetics we know why this happens, but in the brain, we really don’t. And there’s no way, with the techniques we currently have, especially for human investigation, to account for all of these important and likely highly relevant variables and interrelationships – it’s just too complicated. This illustrates very nicely that it is difficult to study something so complex as the brain. Our approaches thus far have been either to massively simplify, which is an approach analogous to what physicists have done to good effect for years, or to under-appreciate and thus not account for complexity. The relative merit to each is difficult to measure. As someone who likes to think about things from the molecular perspective, I prefer to ask the minimalist questions and then build them up (a la physics), and so I find psychology experiments very unsatisfying. But psychologists would argue that if we keep close watch on the limitations of whole human brain experiments, that these broad studies are the best way to learn about the brain functioning as an entire entity in a real person.

      Regarding the cause and effect of different environments on brain function. As I said in the blog – it’s still completely unknown. Also, while it is tempting to think that production line work would require more alertness, and indeed this is probably the case in theory, I think you may find that in practice it is very difficult for people doing this work to maintain a safe level of vigilance. This is due to things like working hours, lifestyle factors of people who have these jobs, and for lack of better terminology, ‘dulling’ due to repetition. So it’s not as clear cut in practice as in theory.

      All interesting questions to ponder. Thanks again!

  • What a fascinating blog. I can remember some fairly vivid and complex dreams and it has always fascinated me. I remember reading that you can’t read something in a dream but from last nights dreams can remember fragments of a limerick that someone made up in my dream. And I can remember colours from dreams as well.
    If I remember part of a dream I can usually remember other dreams that I have had that night.
    It is a fascinating area of study, and one prone to a bit of pseudoscience as well.

    • Thanks for reading and for the kind remarks. Wow! You are quite the dreamer. Yeh, I didn’t get into the more nefarious aspects of dream “research”, but as you will likely know there is a vast area of dream interpretation. Finding meaning in our dreams is something that people have been doing for a very long time. There are entire “industries” built up around using dreams for prediction, personality assessment, conflict resolution, etc. There are no data (real scientifically valid studies that is) that demonstrate that dreams are anything more than cobbled-together snippets of memories that our brain toys with, and randomly stuffs together in weird and sometimes disturbing ways, when it is not otherwise occupied by the hard task of consciousness. Dreaming really seems to be our brain at play, and anything goes!

  • But of course some of us can read in our dreams and much more! When at stage 2 maths level at uni a lifetime ago, I was tutoring stage 1 students and I once dreamt a method of metaphorically explaining how to translate from one logarithmic base to another (even now I can recall smidgeons of the explanation, although I’ve forgotten how to do the maths). It was delightfully elegant.
    Nowadays I’m regularly shot (dead), have large aircraft crashing nearby and the like. It’s all rather exciting! I deliberately do not watch violent TV or films.
    I am very sensitive to the sound of my name when awake.

  • On the question of unscientific investigations of dreams, I wonder what your opinion would be of Freud’s investigations of dreams, which were central to his ideas of the unconscious and its relation to the conscious. His analysis seems very convincing to me, although I don’t know that you could describe it as scientific because it is all basically unverifiable. I think he had a theory of why dreams are so difficult to remember too, possibly related to the way conscious thought suppresses is unconscious foundation.

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