Hesperus is Bosphorus

A group blog by philosophers in and from Turkey

I have a dream! But I can’t remember it…

with 6 comments

In my previous post, “Is Truth Beneficial and/or Socially Constructed?,” I mentioned as a counterexample to the pragmatist theory of truth a nightmare a person had which she did not tell anyone about and kept as a secret for the rest of her life. The nightmare was so horrible and embarrassing that every time she remembered her nightmare, she was disturbed. Her life became a nightmare of sorts because of that nightmare.

Actually this kind of scenario is very rare in real life. The fact is that we tend to forget our dreams and nightmares soon after waking up. Even before we get up from bed, most of the content of our dream has already evaporated from our memory. We remember only very few, if any, of our dreams and nightmares in the rest of our lives. The ones we remember for a while are the ones which were extremely interesting or shocking for us, or those we had the chance to tell other people about on many occasions, which kept our memory of them alive. Ask yourself how many of your dreams and nightmares you still remember. I bet very few, if any.

The interesting thing is that we forget even the most vivid of our dreams and most frightful of our nightmares in the twinkling of an eye (unless our memory of them is reinforced by telling other people about them or by intentional recalling, for example). We forget our dreams even though some of them are more vibrant than certain waking experiences which we remember for much longer time.

Psychologists and brain physiologists tell us that dreams serve a useful function for our brain. So we have to have them. But it seems we also have to forget them fast after having them. I think there is a simple evolutionary explanation of this phenomenon. If we were to remember our dreams long after we woke up, we would be disposed to confuse the memories of our dreams with the memories of our waking experiences. Suppose I have a dream in which a friend of mine does something evil to me or an enemy of mine does a big favor for me. If my brain were to retain as lively a memory of that dream as the memories of my real life experiences, I might mistakenly think the contents of my dream correspond to some real experiences of mine that occurred in the past, and my attitude towards my friend or towards my enemy would unnecessarily be affected by that mistake. Such disorientations clearly would have negative survival value and therefore would be blocked by the mechanisms of human evolution. Hence the elusiveness of our dream contents.*

A search on the Internet shows that many people have thought up the idea that our dreams’ fast vanishing from our memory has some evolutionary advantage or other. I found a blog (http://ianwallacedreams.com/who-dreams-wins/) where an idea which is in some ways similar to mine is mentioned by the “dream psychologist” Ian Wallace:

… if our dreams are so important, why do we forget them so easily? … [W]hy do we let them slip away so easily? The answer is that we naturally seem to forget our dreams because of a simple function of how the dreaming process has evolved biologically.

The evolutionary reason that we forget our dreams is so that we can quickly distinguish between our dreams and waking reality when we wake up. Otherwise we might behave like startled dogs woken from dreams of rabbit pursuit, bewildered and slightly psychotic. In our past, we needed to quickly step from the caves of our dreams into a conscious reality so we could fend off sabre toothed tigers and pursue herds of passing Megaloceros.

… Forgetting our dreams was an evolutionary adaptation when we were animals.

This theory finds the basis of an evolutionary explanation of the phenomenon of dream elusiveness in the circumstance that our cave-human ancestors often had to face the precarious reality very fast after they awoke. This may be part of the explanation, but I think it cannot fully explain why we forget our dream contents not only right after we wake up, but for the rest of our life. Why couldn’t our ancestors afford to recall what happened in their pleasant dreams, for instance, when they were safe from enemies and other dangers—say, when they were peacefully contemplating the events of the day after a nice dinner at the cave? The reason, I think, is that, if our dreams were not to be wiped out from our memories for good, we could confuse our dream experiences with our waking experiences, and endure the risks such confusion involves.

But are almost all of our dreams really wiped out from our memories for good? This may not be the case, at least for a number of dreams, because of the fact that sometimes we can tell that some of our dreams are recurrent dreams. Our realization that some of our dreams recur shows that we are able to remember their repeated occurrences in the past. If we had forgotten our dreams entirely, we wouldn’t have been able to tell that some of them recur. Hence, at least some of our dreams may not have become totally inaccessible to our consciousness. Nevertheless, the majority of them should become inaccessible enough to ensure that we won’t mistake them for waking experiences.

——————

* Instead of quickly erasing them, our brain could have tagged our dream contents as “happened in dream,” and tagged contents of our waking experiences as “happened in reality” before sending both of them to our memory. But doing that would seem to be cost-ineffective for the brain, for there seems hardly any benefit in cluttering our long-term memory with useless material derived from the dreams.

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Written by Erdinç Sayan

April 1, 2012 at 9:52 pm

6 Responses

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  1. Hello and thanks for this. I am way behind my dream research readings but is it really the consensus among scientists (or do we have good, evidence-based reasons to think) that (a) having dreams and (b) forgetting our dreams are adaptive (that is, they serve a particular function that enhances the dreamer’s survival chances)? I was under the impression that (a) was very much an open question (for instance, (Flanagan 2000) argues that dreams are epiphenomena and thus are not adaptive), even though I think I agree that majority of researchers are convinced that dreams have an adaptive value.

    But (b) seems much more speculative to me. Again, I am not well-versed in the literature at all. But I am, along with many critics of evolutionary psychology, reluctant to automatically attribute adaptive explanations to mental traits. This kind of so-called “just so stories” ( http://en.wikipedia.org/wiki/Just-so_story ) do sound reasonable (I was unable to come up with objections to your hypothesis) but “sounding reasonable” shouldn’t be enough for settling scientific issues, wouldn’t you agree?* We need corroborating evidence, which is admittedly hard to come by in these issues. And are there any evidence for (b)? Can we test your hypothesis? What observation would make you (or the researchers that share your view) to change your mind?

    * My favorite example is that female orgasm, unlike male orgasm, doesn’t seem to be a biological adaptation, which is highly counter-intuitive. See (Lloyd 2006).

    uygar polat

    April 3, 2012 at 12:33 am

    • is it really the consensus among scientists (or do we have good, evidence-based reasons to think) that (a) having dreams and (b) forgetting our dreams are adaptive (that is, they serve a particular function that enhances the dreamer’s survival chances)? I was under the impression that (a) was very much an open question (for instance, (Flanagan 2000) argues that dreams are epiphenomena and thus are not adaptive), even though I think I agree that majority of researchers are convinced that dreams have an adaptive value.

      Thank you for the questions. I was under the impression that (a) is true, i.e. having dreams is adaptive. However, I am not committed to the truth of (a) in order to assert (b), i.e. that forgetting our dream contents is adaptive, or to put it conversely, not forgetting them would have posed risks to our survival, as we would have been disposed to confusing reality with the dream world. Even if dreams are, as Flanagan thinks, the noises that the brain makes during sleep, the brain has two options: remember them or forget them. Our brain chooses to forget them, unless we make deliberate attempts to remember our dreams, such as writing them down or repeatedly telling other people about them.

      But (b) seems much more speculative to me. Again, I am not well-versed in the literature at all.

      Me neither. I am not even a psychologist or neuroscientist. I am just someone who thinks dreams are interesting. Here is another question I have about dreams. Why are dreams or dream segments more or less coherent episodes, as opposed to being a totally chaotic flux of visual, auditory, etc. bits and pieces of sensa?

      If our dreams were such meaningless phantasmagoria, perhaps Flanagan’s theory would have more bite. Flanagan says that during dreams the cerebral cortex attempts to shape the jumbled flow of memories, images, thoughts, emotions, and desires into a more or less coherent story. Why does the cerebral cortex bother and waste the precious brain “energy and resources” to shape them into a coherent story, if they are nothing but noise? I think I would put some money on dreams’ not being simply noises the operation of the brain produces; they probably have some function that our brains are adapted to carry out. But, as I said, the truth of (b) does not depend on that at all.

      But I am, along with many critics of evolutionary psychology, reluctant to automatically attribute adaptive explanations to mental traits. This kind of so-called “just so stories” ( http://en.wikipedia.org/wiki/Just-so_story ) do sound reasonable (I was unable to come up with objections to your hypothesis) but “sounding reasonable” shouldn’t be enough for settling scientific issues, wouldn’t you agree? We need corroborating evidence, which is admittedly hard to come by in these issues. And are there any evidence for (b)? Can we test your hypothesis? What observation would make you (or the researchers that share your view) to change your mind?

      Fair challenge. My hypothesis is admittedly difficult to test. Evidence may come in the future when the neurophysiological mechanisms of dreams are more fully understood. Analogy: When the biochemical mechanisms of heredity were understood in terms of chromosomes and genes, we found further evidence for evolution: we discovered that there was a lot of genetic overlapping between humans and apes and even other species.

      Another analogy re my hypothesis. Why is it that rotten food smells foul? A plausible evolutionary explanation would be: to keep us away from rotten food, so we won’t risk our survival. But I think concrete evidence for that hypothesis too is hard to come by. It is hard to look into human fossils to piece together the adaptive story of how rotten food came to smell foul for us. Similarly, fossils of our distant ancestors are not going to readily tell us the story of their adaptation to forget their dreams.

      My hypothesis may be difficult to test, but I think it does pass the test of falsifiability. First of all, there may be pathological cases of people who continue to remember their dreams as vividly as their waking experiences. I don’t know if there are such cases, but if there are, it should be easy to observe the kind of difficulties they encounter in their lives because of that pathology. (If there are indeed such cases, I bet they are regarded by the medical science as “pathological” rather than as people having an interesting and harmless gift.) Secondly, the more unethical alternative: Suppose we have the technology to perform alterations in the brains of people to endow them with the trait of having good memories of their dreams. Even better (and more unethically), do it through mutations so that people can pass that trait on to their next generations. Then sit back and watch if the lives of their offspring will become a hell or not—in other words, see if their chances of survival will improve or deteriorate. Proviso: Don’t make such changes in a way that the brains of the persons can tag their dream memories as “happened in dream,” thus enabling them to distinguish reality from dream. In another version of those vicious experiments, you can let the brain of the person to tag dream memories as “happened in dream,” and sit back and watch how the person with such unnecessarily cluttered memory fares in life.

      Could you please let me know, when you catch up with your dream research readings, if you run into someone who advanced an hypothesis similar to mine or an attack on an hypothesis similar to mine?

      Erdinç Sayan

      April 5, 2012 at 2:23 am

  2. Hello Erdinc hocam,

    I wonder about your statement, “Psychologists and brain physiologists tell us that dreams serve a useful function for our brain.” Who do you have in mind? It seems to me that a version of this view is/was primarily defended by those in the Freudian psychoanalytic tradition. It would be great to find out about contemporary researchers defending this view.

    I am not a fan of evolutionary explanations of why we do dream; I share the view that sleep is an evolutionary adaptation but dreams are epiphenomena. As Uygar points out, this view is discussed in detail by Owen Flanagan’s Dreaming Souls (2000), where he puts forward a naturalistic and multidiciplinary account of why we dream. Allan Hobson, a psychiatrist, also argues that dreams are epiphenomena, and they have no meaning whatsoever; though I am less familiar with his work.

    I have not previously thought about your second query, i.e., why we tend to forget our dreams. The account you cite as well as the one you develop are both plausible. However, they are also weak; one –perhaps a Freudian– can offer a similar explanation for why we remember some of our dreams when we remember them. A Freudian may say, one finds out about his oppressed childhood fears through dreams, then seeks to unleash them, say, through psychoanalysis. Thus having remembered these dreams contributes to his survival or fitness or reproductive capacity –all important phenomena in evolutionary accounts.

    This is perhaps not the best example, but my point basically is that one can develop a similar evolutionary explanation of why we remember some of our dreams.

    It seems pretty random to me which dreams I remember and which dreams I forget, and I suspect that dream experiences vary from person to person, even in the same person in her life course. So I am skeptical of the idea that we can form a unifying explanation that will account for why we forget some of our dreams.

    Serife Tekin

    April 4, 2012 at 12:05 am

    • Hi Serife hanim,

      Thanks for the comments.

      I wonder about your statement, “Psychologists and brain physiologists tell us that dreams serve a useful function for our brain.” Who do you have in mind?

      No one in particular, really. I am not a professional dream researcher, as I told Uygar Polat in my response to his comment. But I was under the impression that dreams are good for us. I seem to remember having read about research that studied effects of dream deprivation (not just sleep deprivation) on people. If you constantly wake people up every time they start dreaming (say, at the beginning of their REM sleep), they will be negatively affected by that. For the control group, wake them up too as many times as the experimental group, but during periods when they are not dreaming. A comparison of the experimental and the control groups should reveal differences in the severity of their negative responses to the experiment. Flanagan would explain the differences differently, without putting the dreams themselves at the center of his explanation.

      I am not a fan of evolutionary explanations of why we do dream; I share the view that sleep is an evolutionary adaptation but dreams are epiphenomena. As Uygar points out, this view is discussed in detail by Owen Flanagan’s Dreaming Souls (2000), where he puts forward a naturalistic and multidiciplinary account of why we dream. Allan Hobson, a psychiatrist, also argues that dreams are epiphenomena, and they have no meaning whatsoever; though I am less familiar with his work.

      I had a few words to say about the epiphenomenalist theory in my response to Uygar. The crucial point is that my hypothesis, which states that dream forgetfulness has survival advantage, can be defended even if dreams are epiphenomena.

      I have not previously thought about your second query, i.e., why we tend to forget our dreams. The account you cite as well as the one you develop are both plausible. However, they are also weak; one –perhaps a Freudian– can offer a similar explanation for why we remember some of our dreams when we remember them. A Freudian may say, one finds out about his oppressed childhood fears through dreams, then seeks to unleash them, say, through psychoanalysis. Thus having remembered these dreams contributes to his survival or fitness or reproductive capacity –all important phenomena in evolutionary accounts.

      This is perhaps not the best example, but my point basically is that one can develop a similar evolutionary explanation of why we remember some of our dreams.

      My hypothesis is not about why we remember some of our dreams (for a while), but why we typically forget very fast a great majority of the dreams that we wake up in the middle of. About the dreams we spontaneously remember (i.e. without reinforcing our memory of them through deliberate recollection or jotting them down, etc.), Freudians may be right (or wrong). But my hypothesis is not a rival to a Freudian or any other account of why we remember some of our dreams.

      It seems pretty random to me which dreams I remember and which dreams I forget, and I suspect that dream experiences vary from person to person, even in the same person in her life course. So I am skeptical of the idea that we can form a unifying explanation that will account for why we forget some of our dreams.

      My point is not that we forget some of our dreams. I claim that we forget all of our untold number of dreams, including very vivid ones, save for very few of them. (See, however, sarauckelman’s interesting story in her comment below.) And I offer an explanation of this widely known phenomenon.

      Erdinç Sayan

      April 6, 2012 at 4:39 am

  3. Actually this kind of scenario is very rare in real life. The fact is that we tend to forget our dreams and nightmares soon after waking up.

    Because the plural of anecdote is data :), I’d like to respond contra to this.

    I have always had vivid and memorable dreams, to the point where 4/7 nights a week I wake up and can relate in detail my dreams to my husband (who marvels at them both due to their detail, their content, and the fact that he rarely dreams or remember any of his dreams; but to that point we have an interesting piece of data, namely when he doesn’t drink coffee, he is much more apt to remember his dreams when he does have them). The vividness of dreams and a person’s ability to recollect them are skills that to some extent can be developed, cf. for example people who work on lucid dreaming (http://www.newappsblog.com/2011/11/lucid-dreaming-i-dream-that-i-know-that-i-am-dreaming.html). I can still describe in minute detail some of the dreams I had as a child, particularly recurring nightmares. While my memories of these dreams are reinforced by revisiting them, the same is true of my memories of reality; in fact, I’d say that up to a certain age, my memories of reality and my memories of dreams are probably about equal in number and strength.

    But more importantly to your point
    If my brain were to retain as lively a memory of that dream as the memories of my real life experiences, I might mistakenly think the contents of my dream correspond to some real experiences of mine that occurred in the past, and my attitude towards my friend or towards my enemy would unnecessarily be affected by that mistake.“, I have had dreams precisely of this sort, that have had a profound impact on my life and my attitudes/behavior towards other people, even though I know that they are dreams. Before my husband and I were officially dating, but were on the way to it, I once dreamt that he’d invited me out to lunch because he wanted to introduce me to someone very important to him, and it turned out to be his (nonexistent in real life) girl friend from back home and 3 year old daughter. I knew it was a dream, but it was so vivid, and I was so hurt by it, that it took me most of the weekend before I could “forgive” him. (It still raises some ire whenever I remember it!). I have also had other dreams which, for whatever reason, fundamentally changed the way that I viewed another person; such dreams have affected my interactions with these people in long term ways even though I have never divulged the details to anyone.

    sarauckelman

    April 5, 2012 at 4:16 pm

    • Thank you for the fascinating comment!

      I have always had vivid and memorable dreams, to the point where 4/7 nights a week I wake up and can relate in detail my dreams to my husband (who marvels at them both due to their detail, their content, and the fact that he rarely dreams or remember any of his dreams;

      I guess he is typical. I am like him myself. But you are extraordinary.

      but to that point we have an interesting piece of data, namely when he doesn’t drink coffee, he is much more apt to remember his dreams when he does have them).

      There’s is a topic for dream-recall research…

      The vividness of dreams and a person’s ability to recollect them are skills that to some extent can be developed, cf. for example people who work on lucid dreaming (http://www.newappsblog.com/2011/11/lucid-dreaming-i-dream-that-i-know-that-i-am-dreaming.html).

      Interesting to know. Thanks.

      I can still describe in minute detail some of the dreams I had as a child, particularly recurring nightmares. While my memories of these dreams are reinforced by revisiting them, the same is true of my memories of reality; in fact, I’d say that up to a certain age, my memories of reality and my memories of dreams are probably about equal in number and strength.

      Wow! That is amazing…

      But more importantly to your point
      “If my brain were to retain as lively a memory of that dream as the memories of my real life experiences, I might mistakenly think the contents of my dream correspond to some real experiences of mine that occurred in the past, and my attitude towards my friend or towards my enemy would unnecessarily be affected by that mistake.”, I have had dreams precisely of this sort, that have had a profound impact on my life and my attitudes/behavior towards other people, even though I know that they are dreams. Before my husband and I were officially dating, but were on the way to it, I once dreamt that he’d invited me out to lunch because he wanted to introduce me to someone very important to him, and it turned out to be his (nonexistent in real life) girl friend from back home and 3 year old daughter. I knew it was a dream, but it was so vivid, and I was so hurt by it, that it took me most of the weekend before I could “forgive” him. (It still raises some ire whenever I remember it!).

      That is so funny! Well, I guess you’d agree that remembering our dreams can be a serious handicap. I can imagine situations in which it can even be life threatening. But you are lucky in that your brain does tell you it happened in dream, not in reality. (This was what I meant in the footnote of my post by the brain tagging one’s memories as “in dream” and “in reality.”) If your brain hadn’t done that, you would probably have refused to marry the poor guy. :)

      I have also had other dreams which, for whatever reason, fundamentally changed the way that I viewed another person; such dreams have affected my interactions with these people in long term ways even though I have never divulged the details to anyone.

      Very interesting. I am terribly sorry to have conjectured in my response to Uygar Polat’s comment above, that remembering of dreams as vividly as waking experiences would probably be regarded by the medical science as “pathological.” In your case, since you can differentiate between the memory of a dream and the memory of a waking experience, you can avoid (with some difficulty apparently) the negative effects of your deceitful dreams. But if I may ask, would you be happier if you just forgot most of your dreams like most of the rest of us—especially if you were utterly unable to tell a dream memory from the memory of a real experience?

      Erdinç Sayan

      April 7, 2012 at 2:48 am


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