About a few hours ago, I had a strange dream that continued even after I woke up and went back to sleep…it was something like a past life in a futuristic espionage setting. I got up and wrote down all sorts of things from it. Now I can’t remember much and when I read the things I wrote…it’s really tough for me to remember or even understand it. Why are the memories from the dream so vivid when we first wake up and then they slowly dissapear from our memories?
-M
I’ve heard it’s due to a release of melatonin right after you wake up. I’d research it but it’s getting late 
Purely from an adaptation point of view, it makes sense. (If you forget that dreams make no sense to begin with). If we could remember dreams, we would likely get confused after a while as to whether what we remember was real or not. No advantages to that.
Dreams do not always make for easily interpreted impressions. In a hypnotic state, one is not always able to describe precise thoughts that are occurring. However, it is often a simple matter to convey feelings and sensations during the same exact sequence of remembered events. Dreams do not occur in completely sentient terms. They are a synopsis of prior and current experience modified by any anxieties or fixations. A dream can often seem to involve hours of experience yet happen in a few minutes. So it is with the language of dreams. It is a hyper-compressed string of complex scenarios and emotionally loaded vignettes that can help resolve internal conflicts or confusion.
Most people are unfamiliar with how to retain a dream’s seemingly random sequence of events. It requires a raconteur’s knack for narrative and the willingness to strip bare one’s deepest insecurities and motivations. Keeping a journal is a productive way of training your mind to accept dream images as more commonplace. A significant challenge is *active dreaming *, whereby an individual learns to initiate volitional acts and take control in their dreams. Many times I have come ‘awake’ in my dreams, fully cognizant that I was in a dream state. Adherents of active dreaming recommend attempting to look at one’s hands as a first step towards steering one’s dreams.
Another factor that completely compromises a person’s ability to recall their dreams is any sort of abrupt awakening. Restoration of limbic processing reactivates higher locomotor functions that wipe clean the elusive sketches we find on dreamland’s slate. Being jolted into wakefulness nearly guarantees little if any retention of a dream’s content. If you wish to explore your resting state, get eight hours of sleep with a gradual and voluntary awakening. Do not awaken to music or radio as their content can supplant internal themes you need to remember. Even soft chirping alarms can reduce retention of content.
An improved understanding of dreams can provide a unique window onto the landscape of our mind and soul. Journeying the realm of our subconscious is an adventure like no other. Our lives and hearts lay open for the changing within our dreams. We need only to understand how accurately they can reflect the life story within each of us.
Try googling “Sleep induced amnesia”
Here’s one link: http://ist-socrates.berkeley.edu/~psy001/jk/psych1mem3.html
" Most investigators explain sleep-induced amnesia in terms of an encoding deficit or consolidation failure. According to this view, the low levels of cortical arousal characteristic of sleep effectively impair complex information-processing functions. Thus, events in the environment are not noticed, relevant information in memory is not retrieved, and traces of new experiences are not encoded in retrievable form. "
you might want to also check out the lucid dreaming faq
theres probably some information there you would be interested in…
You might want to try getting into the habit of keeping a dream journal (and pen, by your bedside). Some people find that the more practice they get in recalling and writing down the details of their dreams, the better those skills become.
I have been told that most people who find it difficult to remember their dreams find it so because they’ve never really tried it before. If you view recalling dreams as a skill, as riding a bicycle is a skill, then it makes sense. Few people are able to ride a bike or ride one well the first few times they try it. They need practice before they become comfortable with it, and even more practice before they become good at it.
One thing that has helped me remember my dreams-- and remember things in general-- is associating them with other things. For example, I once had a dream where I was being chased through what appeared to be the backstage of a theater, except it was at the top of a large condominium. This theater reminded me of my high school’s, and the condo resembled the Empire State Building. When I briefly awoke just after the dream, I thought of those two places: my high school and the Empire State Building. The dream wasn’t particularly outstanding, but years later I still remember it. I’m not sure I would have remembered it longer than ten minuted had I not formed associations.
You’re not likely to be able to associate things in your dream with my high school ;). But maybe your dreams will hold things you can associate with other things. Maybe the scene where your dream takes place will resemble a scene from a movie, or a person in your dream will look or sound just like a celebrity or friend of yours. These associations won’t always come, or come easily. It’s usually difficult to think when you’re mostly asleep. But by making an association between something you’re likelier to remember later, you may help yourself remember the dream details associated with it.
Certain persons “on business from Porlock” have been known to be the culprit.
My uncle used to dream great poetry in his sleep, but could never remember it upon waking. Someone told him to keep a pen and paper by his bed, which he did.
The result?
“She was the white on the barber pole.
I was the red, God bless my soul.”
He stopped dreaming that he was writing great poetry…
Trinopus
Quoth Zenster:
Not really, seeing as you don’t remember a dream at all unless you wake up during it. I suppose it’s possible to wake up gradually during a dream, but that’d be pretty difficult to arrange.
I used to keep a pen & sheet of paper by the bed to make notes.
I divided the paper into 16 sections, each concerning a different aspect of dreams, to make it easier to remember.
I did quite a few then realised it was all a bit stupid and threw them all out. No point hangin onto memories of things you havnt even really done, its hard enough trying to remember things I have done !
It’s called “State-dependant memory.”
If we experience something during an abnormal mental state, then the memories are somehow stored differently. Then we have to be in the same state to have access to those memories.
The classic example: cramming for a test without sleeping for a couple of days. Then getting a good night’s sleep before the test. All the information learned during sleepless cramming becomes VERY hard to dredge up.
I’ve sometimes been able to remember dreams days later, simply by trying to recall the old dreams in the early morning while first waking up.
A running joke in my college psych-101 class was that we must stay drunk when studying, that way all our knowledge is stored in a well known “state” in our minds. To access those memories and do well on the final exam, just drink a bunch of beers first. 
funny, my problem is that dreams are most vivid, whereas I can’t remember more than a moments worth of waking life.
So here are some neurological WAG:
Top-down stuff (dreams and mental imagery are the two biggies) doesn’t activate very much low level stuff. This is why dreams are kinda wonky visually when you look at details, the early visual system information of edges and the like isn’t getting well activated. When you wake up, especially if there is a good light source, external information floods the system and the dream information if going to be cleared out. Because the dream experience activation is gone you now have only the temporary increases in connection weights between involved neurons. While the mechanisms of neural connection increase/decrease aren’t fully mapped out there is a fair deal of evidence that short-term connections can be strong but leave pretty much no lasting impression. More coherent and emotionally charged dreams have better memory because in the first case you have existing connections to support the new ones and in the second you have the general somewhat nebulous advantage of emotion on memory persistence but also you are more likley to talk about the dream. Talking about memories, including memories of dreams, reinforces the connections and provides new ones for the context that the memory is being brought up in. This is extendable to keeping a dream journal. You promote the connections that otherwise would just die for lack of supporters.
It’s also known as state-dependent learning, which basically says that you are best able to recall or perform on a test of something if you are tested in the same state in which you learned or experienced the material. So if you studied for your organic chemistry final while drunk, you’ll (in theory) do better on the test if you take it while drunk.
Though I’m not sure how long you can stay in a dreamlike state while trying to remember something. I imagine you’d either fall back asleep or wake up fully.
Based on what I know about memory, I agree with The Tim’s WAG.
I’ve always assumed the reason we can’t remember our dreams was the evolutionary angle that Nanoda suggested. For all I know every animal that sleeps also dreams. I know dogs, cats and mice do. I would think it would be very confusing to these animals if they remembered their dreams as vividly as they remember reality.