Science Questions

Why can't we remember our dreams?

Sun, 6th Jul 2008

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Question

Paula Ogilvie, Johannesburg, SA asked:

I was wondering why it was so difficult for us to remember our dreams when we wake up in the morning?

Answer

Professor Mark Blagrove, Professor of Psychology at Swansea University:

People differ on whether or not they can remember their dreams.  Self-portrait of Joseph DucreuxSome people have a great deal of interest in their dreams, have very vivid dreams or their level of anxiety or sleep quality results in people remembering dreams at different amounts each month, say.  In general, for all of us dreams are very easily forgotten once we wake up if we donít consolidate them or in other words if we donít transfer them from short-term to long term memory immediately upon waking. 

Thereís a few theories of why that happens to all of us.  One possibility is that our brain neuro-chemicals during sleep are very different from during wake time and so they donít allow us to consolidate memory.  The other thing thatís quite possible is that we donít pay attention to our dreams or are unable to do so during sleep.  We are unable to remember what occurs to us during sleep.  Even people with sleep apnoea who wake up during the night donít know that that happens to them.

Similarly when we have a dream weíre not consolidating it as it occurs.  Indeed, if you have people having a long REM sleep period and you wake them up once the REM sleep period gets over about 20 minutes you donít find that dreams increase in length very much.  Itís as if during the dream we forget what was happening.  The same happens immediately we wake up.  The dream just disappears.

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I've heard this answered on the naked scientists before i'm sure. I think it was because there are parts of the frontal lobe that are inactive during REM sleep cycles, and these are the parts usually associated with memory and thinking critically. Madidus_Scientia, Wed, 2nd Jul 2008

But you do remember some dreams don't you? So why the difference? chris, Thu, 3rd Jul 2008

Yeah and even when you can remember a dream with all its details when you've just woken up, sometimes by the time you get to work and you think about it again you can only remember it very vaguely if at all, as if your brain deleted the file! Well that happens to me at least anyway. But then you can remember some other dreams very vividly and remember them for the rest of your life.

By the way, does anyone know how much those people that get their brain studied while they sleep get paid? That would be my dream job! :P Madidus_Scientia, Fri, 4th Jul 2008

But don't they also get woken up every time they start to dream? Doesn't sound like much fun to me. Geez, I've got a daughter that takes care of that for me...maybe I should just volunteer for the study and have a home rig to record my brain activity... chris, Fri, 4th Jul 2008

I have absolutely no scientific basis for this, it's simply my own observation, but from my days as an undergrad it seemed like I can get the same amount of "dreaming" (as measured in "perceived length of the dream") done off of a 20 minute nap in class as from a good 6-8 hours on the weekend. So, if sleep time doesn't have any effect on dream time, then it makes sense that any dreams we "remember" are simply the random creations we come up with at that brief moment of waking up. And if you'll permit a computer science analogy, it seems to me that dreams are just what happens when you read uninitialized memory after turning the power on. In other words, our brains are off in crazy rest/sleep mode, and switching back to awake mode leaves a lot of stuff all garbled, and we interpret that as dreams. If that's true, then it makes sense that it's hard to remember because those "experiences" aren't attached to anything, just random thoughts. And there's all sorts of information about memory being enhanced (if not entirely based) on being attached relations to other ideas/sensory experiences. So that's my guess. Sorry it's all just conjecture though...

(And by the same token, that probably supports "traumatic bad dreams" sticking with us, because we immediately associate them with the traumatic ideas/memories we have in real life, causing them to stick.)

Anyway, I'm curious to see if this is at all supported by research out there =P Crypticfortune, Sun, 6th Jul 2008

Interesting thought. thanks. We're you in SL on Sunday? chris, Tue, 8th Jul 2008

yup, I was. I'll be there again tonight. looking forward to another excellent show ^^ Crypticfortune, Sun, 27th Jul 2008

I actually remember dreams from when I was real little, they were either nightmares or just a vivid dream that's hard to forget. I think it's like recalling a memory of something that happened only it being a dream. You can remind yourself of that memory and it doesn't really go away. Journals do help if you have trouble recalling but also try to think of what you dreamed as a memory, it may help. kdwelch, Fri, 8th Aug 2008

so when we dont remember are dreams its because the dream doesn get taken to the long term memory..but some times u juss remember a picture instead of the acuall video dream..but then why are some dreams longer than others is it because when we have shorter dreams it took us a long time to drift into a deep sleep?? does not remembering ur dreams have some thing to do with the amount of sleep u get?? does age have to do with it?? a friend of mine hasent had a dream scince he was 10 i think why that really?? tamera, Mon, 18th Aug 2008

My grandson passed in June& I have not had a dream about him at all, why? He was the love of my life. My oldest sister passed in 2000 & my dad passed in 2004 & have not had a dream about none of them. Why? Why? Why? Help! Lafu, Thu, 11th Sep 2008

maybe you have dreamt about them.. but you just can't remember.. Chinita09, Sun, 13th Sep 2009

Wow that is very sad? Paul, Tue, 26th Jan 2010

I love my dreams Ben Love, Tue, 26th Jan 2010

I agree that my dreams sometimes seem just as long in a 30 minute nap as in a full nights sleep. They aren't just random thoughts though, because sometimes I can realize I am dreaming and actually control what I am doing in my dream. Dreams are crazy. Matt, Fri, 29th Jan 2010

I understand... when I have a desire to see or spend time with a person that is no longer with me I try to dream with them to make it as vivid as possible. What I have tryed is thinking and have a picture of them as I go to sleep, sometimes it works and sometime it doesn't. As I understand dreams usually occur at the end of your sleep so dreaming what you want to dream may not happen. owl16, Wed, 22nd Sep 2010

you dont remember them because when youre dreaming your in a different state of consiousness. bernhard, Thu, 20th Jan 2011

The most annoying thing is during the day you get a flash in your mind of the previous nights dream and you think "Oh yes, that was what I dreamt last night" ... but then 2 seconds later it has gone completely - you can't even recall what you thought in the previous second at all ... or is that just me? :( Highpeak, Fri, 10th Jun 2011

Time to free up the ol ora from interpretating and sending energies That create mood.finally off to fuel the spirit with the tools our only our subconscious knows we need to battle What is destined.. kelly, Sun, 27th May 2012

I have always remembered most dreams.I think about them right away, then write them down.Lately tho I barely remember any! Maybe fragments- it drives me nuts- while I'm dreaming,Iknow it., and theres so much going on! How can i not remember now, when i could before? yes,sometimes I get a flash of a dream hours later- gone before I can catch it hate that too! jan, Mon, 25th Jun 2012

Dreams and Programming Neural Networks

In 1989, at a DECUS conference, I attended a presentation on neural networks in which the presenter (Curt Snyder) described a technique he had developed to clear out 'bad' connections.

A typical way to train computer neural networks is to present them with a series of input data sets (such as photographs of woodlands either containing a tank or not). The neural network responds with its evaluation (yes/no) and then the programmer provides feedback to the neural network (yes there was a tank/no there was not), either strengthening the existing connections or weakening them.

The presenter explained how bad associations tend to build up and are hard to remove. The technique he developed was, to the best of my recollection:

1) Store the current state (State A) of the neural net; all of the interconnection values.
2) Feed the net random inputs and observe its responses.
3) Provide random feedback to those responses.
4) Calculate the connection differences (State B) that built up during this process (what it learned).
5) Subtract from State A the connection values it learned during the process; (State A) - (State B).

After his talk, I suggested to the speaker that this seemed much like dreaming. A sort of random series of experiences, forgotten upon waking. He didnít. He didn't seem to find the comparison compelling, but I've always thought the two processes seemed so similar that it warranted investigation. AndroidNeox, Wed, 28th May 2014

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