All of this, Barrett notes, led many researchers to conclude that dreaming was necessary for one or more of these functions: to replenish neurotransmitters, rest a particular brain area, or restore the thermoregulatory system. In general, these brain conditioning theories don’t place much, if any, emphasis on dream content. As psychologist Steven Pinker writes, “For all we know, dreaming might be a kind of screen saver in which it doesn’t really matter what the content is as long as certain parts of the brain are active.”
External Vigilance
University of California at Santa Barbara anthropologist Don Symons wasn’t entirely satisfied by brain conditioning theories of dreaming, in large part because these theories didn’t really crack the question of why dreams have such a specific sensory profile of being so vividly visual and kinesthetic while comparatively impoverished in sound, smell and other sensory domains. Symons points out that sleepers are particularly vulnerable to real-world threats and hazards in their external environment, and so they must unconsciously monitor their environment with specific senses. For example, if our ancestors were busy having olfactory or auditory hallucinations in their dreams that were equally as rich as their visual hallucinations occurring beneath their fluttering eyelids, well then they might not have noticed the ominous smell of smoke creeping up their nostrils or the threatening strangers or predators pattering around outside. Being a “light sleeper” in relation to these other sensory domains had adaptive benefits, and since we’re in the dark anyway and our eyes are closed, there’s less of a risk in hallucinating in our secret visual worlds while our brains are being recharged through the processes described in the previous section.
Threat Simulation Theory
Originally proposed by Finnish neuroscientist Antti Revonsuo, this clever evolutionary theory holds that dreaming serves a biologically adaptive function because it allowed our ancestors to simulate problem-solving strategies for genuine, waking life threats. Antonio Zadra, Sophie Desjardins, and Eric Marcotte of the University of Montreal neatly summarize the central argument of the theory this way: “By giving rise to a full-scale hallucinatory world of subjective experience during sleep, the dream production mechanism provides an ideal and safe environment for such sustained practice by selecting threatening waking events and simulating them repeatedly in various combinations.” What we should see in contemporary dreams, argues Revonsuo, are “threat scripts” depicting primitive themes of danger that would likely have been relevant in the ancestral environment, such as being chased, falling and so on.
Costly Signaling Theory
Boston University neuroscientist Patrick McNamara has an interesting evolutionary theory of dreaming. McNamara’s theory draws from the well-known “handicapping principle” in evolutionary biology, where some organisms have been observed to display behavioral traits or physical characteristics that seem ostensibly to disadvantage them but in fact simply reflect their genetic value. The classic example of this is “stotting” behavior in healthy young gazelles, where these animals jump up and down in front of a predatory leopard rather than—what would seem to be a smarter move—immediately running away. Stotting is a “costly signal,” but it works, because the leopards take this stotting display as evidence that this particular gazelle is so healthy and fit that it can afford to handicap itself and is therefore unlikely to be an easy target. Usually, the leopard moves onto the sick, old, or young non-stotters.
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Add CommentDreams can help with problem solving on a personal level. Choosing e.g. a change in occupation, I would put my logical brain to work, making a list of advantages and disadvantages.
Reply | Report Abuse | Link to thisSometimes, on sleeping on it, a dream would reveal in vivid but bizarre images, what I subconsciously wanted. That could be added to the list of advantages. It did not let me down.
As a sometime lucid dreamer, I'd suggest Robert Waggoner's book 'Lucid Dreaming: A guide to the Inner Self" for another explanation of dreaming, My reaction on awakening from my own bizarre dream scenarios is typically, "Rats, didn't realize I was dreaming this time, either!" The oddity of any particular dream is for anyone who has experienced the intensity and exhilaration of lucid dreaming, completely explicable as an invitation from our next-to-last frontier to expand our so far undeveloped night time consciousness.
Reply | Report Abuse | Link to thisi use dreaming in two ways--1--I play my Accelerated Learning spanish music/language tapes as i am drifting off to sleep. I cannot say if this has helped me learn faster, but it does have the effect of making it easier to distinguish individual sounds, whereas before, all i heard was mumble, mumble. and --2--i review a problem just before sleep and in the morning i wake up with a solution.
Reply | Report Abuse | Link to thisWe should be careful not to characterize every trait as an adaptation and then look for a fitness advantage to said trait. As long as the trait confers no obvious fitness cost it does not require such an explanation. Dreaming could be a purely happenstance event; or, it could be the neutral consequence of some trait that has been selected for. By universally applying the adaption criterion we risk missing simpler and potentially more testable explanations for traits. Some characteristics are the consequences of processes of development or simply random mutation. Natural selection can not act on neutral traits, and it has a very limited ability to act on traits that are not simple, independent, and continuous.
Reply | Report Abuse | Link to thisThis doesn't mention the most plausible theory -- that of Reiser and others: that dreaming is a memory storage technique, taking the content of the day and associating it with powerful emotional experiences (thus often from childhood), so that meaningful content is stored permanently, while meaningless content is jettisoned. The evolutionary benefits of this technique are obvious.
Reply | Report Abuse | Link to thisWithout accepting ... Read MoreFreud's discredited "wish-fulfillment" theory, Reiser's explanation and the neuroscientific evidence that supports it vindicate the main tenets of dream analysis: that the "manifest content" of the dream disguises its meaning, that the "day residue" contributes to this meaning, but that a deeper contribution, the "latent content" comes from an idiosyncratic emotional meaning.
Interesting thoughts, I would posit another possibility, along the lines of Patrick's suggestion on Memory storage. Among my interests is Machine Learning, in thinking about how the brain works, it seems that in order to be an efficient information processing organ, we must be fully capable of "imagining" or "beholding or "envisioning" the world-space we perceive, before making sense of new input perception. If not, then we would not be able to have "live consciousness". Looking at biological vision system it is a similar story, our brain helps to make a continuous and meaningful representation of objects by filling in missing pieces (just think of all the things we "see" that aren't really there, or upon second examination we see something different). Thus, dreams seem like a consequence of the need to tune this imaginative ability.
Reply | Report Abuse | Link to thisSo, essentially, if one can "dream" it, or imagine it, then one can more fully interact in real time in the real world with meaningful experience. (or course for different mammals, the level of "meaningful" experience is of different level of complexity, ex. dog, dolphin, etc..)
I think it would be safe to say that both the survival and problem solving explanations can be rolled into one. They both address taking in information garnered through the day, processing it and regurgitating a useful response. While we are seldom chased by bears, our ancestors did not have to analyze mathematical formulas. But as far as our nervous system is concerned, they can be one in the same, creating a stress flight or fight adrenaline response.
Reply | Report Abuse | Link to thisThis article is looking at dreaming from a benefit standpoint. It could be a consequence of something else and actually be a cost that is less than a selected benefit. Other work has been done to show that when we sleep, long term memory is stored. I am simplifying the work, but that was the general principle. Perhaps dreams are an offshoot of the activity of memory storage and the reproductive survival cost of waking up confused with weird thoughts in your head (occasionally from those few dreams we remember) was outweighed by the benefit of having good long term memory. There are so many ways to evaluate this, that without a testable hypothesis, it will be all random speculation. It's a fun topic, but still speculation.
Reply | Report Abuse | Link to thisA theory I find interesting is that REM sleep could serve a similar function to an OS updating important software. An OS can't update, modify, or improve deep underlying code without first stopping normal function of the system e.g. the Linux kernel.
Reply | Report Abuse | Link to thisI subscribe to Scenario Theory which states that the mind organizes experience into Scenarios - which are actually a recursive interrelationship between other Scenarios - such that when we are dreaming we are "Scenario Testing" - looking for the best way to navigate any of the bazzillion possible combinations.
Reply | Report Abuse | Link to thisAs we Scenario Test we are adjusting the weights of our "neural network" in a way that favors successful outcomes, and leads us away from unsuccessful outcomes - and rules out extraneous unnecessary possibllities.
This is why recent studies shows that we remember our experiences better after we have dreamed.
My brain once solved an adjourned chess game while I was sleeping. On another occasion I fell out of bed and it had time to provide a parachuting dream (without a parachute) before I hit the floor.
Reply | Report Abuse | Link to thisI am of the opinion that dreams: happen quickly; are a biproduct of our brain ordering and editing the previous days inputs and that there is a problem solving aspect although since dreams are "visual", rather than verbal, it is usually a cryptic answer provided.
While the body is at rest it allows time for repairs. I imagine there is time for circuit testing and running "what if?" scenarios. It may be that the subconcious mind is "running the show" with small interjections from the concious mind. Like the opposite of daydreaming.
Sleep leaves the individal vulnerable, yet many species sleep or even hibernate. This would suggest that sleep has a vital role.
As Edward Monkton says.... Live your dreams; except the one where you get eaten by the giant spider.
i agree with prometheus8128. why must all events and traits be seen as evolutionary ? this reductive view masks other fascinating aspects of complex aggregate systems: by-products. my own dream experiences range from the apparently random to the seemingly cosmic. i've solved problems, gained insights, even shared vaguely clairvoyant links, yet most of my dreams feel like the random firing, or "winding down" of neural pathways that were most exercised on any given day. A by-product of the day's intensity and the organizational tendencies of my organic super-computer.
Reply | Report Abuse | Link to thisAbout the "memory storage" theory:
Reply | Report Abuse | Link to thisI know artificial neural networks are hugely simplified models of what goes on in a real brain, but I've always thought it was pretty compelling that even artificial neural networks (that can be trained to store and recognize patterns) benefit from "dreaming". An artificial network "dreams" when you disconnect the inputs from any stimulus, and instead feed the inputs from the outputs, causing the network to go into a memory-reinforcement mode where the basins for recognizing a pattern are narrowed.
Essentially, a network that doesn't dream will see a Ferrari, and think "That's my car." While a network that dreams can think "Wait...I don't have a Ferrari."
One of the vital functions of sleep is to allow for the downloading of short term memories into long term storage, a process that relies in part on matching patterns between short and long term memories. Because this is a "CPU" intensive process, it cannot be "run" during waking hours or it would "crash" or "overload" the mind and create confusion between the real world and the rapidly cycling phantom world of randomly matched memories. Hence the need for memory storage is a key reason for sleep and dreams.
Reply | Report Abuse | Link to thisThe evolutionary benefit of having long term storage of memories and lesson learned is an invaluable resource for improving ones chances for survival. In fact the benefit is so great the bodys chemistry heavily penalizes it when it undergoes extended periods of sleeplessness.
The random pattern matching occurring during REM sleep is an intensive process that cannot be sustained all night long. Hence the need for progressive sleep cycles that alternately rest the mind and then subject it to intensive memory storage activity.
Problems are solved during dreaming when matches between short and long term memories are profound enough to trigger an emotional response strong enough to wake the sleeper. Otherwise the problem is solved the next day when a return to the subject matter activates retrieval of the new link to the stored solution.
Weird dreams are merely random jumbles of images that got served up during random pattern-matching . They tend to be stressful when they link to stored threat memories. If the emotion is strong enough the bad dream itself can get embedded in long term storage. Under the right (wrong?) conditions excessive links get wired to the bad dream memory and after a while all roads lead to Rome . That is to say, the bad dream memory becomes an iconic memory for a range of everyday anxieties and fears and is resurfaced again and again. Recurring bad dreams may be the results of myriads of links laid down to the same threat.
Our dreams are connected to our daily activities, I find that if I have had a very stressfull day then my dreams are very vivid and troubling. I will sometimes act out my dreams as I have rem sleep disorder.
Reply | Report Abuse | Link to thisAll the comments and the article focused on visual dreams, I have always wondered what are the dreams of a person that has been blind from birth like?
Dreams have multiple purposes (involving "all of the above"), and those purposes can be mixed together in the same dream sequence. Basically dreams are testing strategies for present and future problems, re-examining past strategies as part of the process. And we only "see" a part of the dream when the brain puts on a little "visual" drama - telling itself stories, so to speak - since story telling is how we have always formed and passed on our strategic lessons to others as well as to ourselves. Most importantly, it's the absence of sensory input from the outside world that makes the phenomena seem so bizarre in retrospect, even though these "dreams" are likely occurring in some continuous fashion whether in a sleep state or not.
Reply | Report Abuse | Link to thisI don't find these arguments persuasive. The content of dreams and the means of solving problems (if solved) more often than not aren't at all transferable to waking life. It's possible that dreaming is simply a by-product of some other function. Either way there isn't any contradiction between evolutionary people and the Jungians. For example, if dreams evolved to rehearse and deal with threats, what is perceived as a threat is obviously shaped by our experiences: there weren't any elevators in the good old days when human brains evolved. So if a particular experience has been very upsetting then talking about it can make it less upsetting and so no longer the content of dreams. People who've been traumatized often have years of nightmares that abate as the trauma is talked about with a therapist.
Reply | Report Abuse | Link to thisNone of these theories explain why depressed people dream up to three times as much than the non-depressed-or why not dreaming causes mania.
Reply | Report Abuse | Link to thisI'm really surprised that Joe Griffin's work on the 'Expectation fulfilment theory' of dreaming wasn't included here after all it's been around for years and ties up all the physical and psychological angles of dreaming http://www.why-we-dream.com/joe-griffin.htm
Reply | Report Abuse | Link to thisNone of these theories explain why depressed people dream up to three times as much than the non-depressed-or why not dreaming causes mania. I'm really surprised that Joe Griffin's work on the 'Expectation fulfilment theory' of dreaming wasn't included here after all it's been around for years and ties up all the physical and psychological angles of dreaming: http://www.why-we-dream.com/joe-griffin.htm
I enjoyed Barrett's problem solving theory of dreams, however I seem to have better results in this capacity during that stage of sleep where I am just beginning to wake up. At this stage, my mind is like a just-shaken Etch-A-Sketch, open to any and all ideas that happen to float by, and with a seemingly complete lack of bias. As a freelance Graphic Designer, I use this stage of sleep, which I call The Daylight Zone, to come up with creative ideas for logos, posters, Web page headers, etc.
Reply | Report Abuse | Link to thisAnother topic I was looking for in this article, but didn't find, was the role DMT (dimethyltryptamine) plays in dreams. I read that the [illegal] neurotransmitter is most prevalent in the brain during REM sleep as well as near-death experiences, being released from the pineal gland. Many cultures throughout history have used external sources of DMT to reach "dream states," especially in shamanic practices, religious ritual and mystical revelation.
I don't know if this kind of feelings just happen to me: but I just got a weird thought sometimes that things happening had happened in my dreams long time ago, it is really hard to explain that kind of feeling, just like Dajavu, but I think scientists could work on this: why people always have familiar feelings of what is happening, and why they always refer those feelings to their dreams.
Reply | Report Abuse | Link to thisEvery article about evolutionary psychology has the same assumption. At least here it's spelled out: "its not immediately apparent why natural selection wouldnt have simply engineered a dreamless, non-REM sleep."
Reply | Report Abuse | Link to thisMany facets of human development are just vestiges of other processes; e.g., the tailbone. Humans no longer have a tail, so it's not immediately apparent why natural selection simply wouldn't have engineered a tailbone-less human.
I think dreams are the tailbone of the mind. While the executive function switches off, the underlying random processes that allow us to make connections and be creative are still going on. It's the same thoughts you have during the day, except they don't reach consciousness because they don't make the cut; most are too silly to seriously consider when your guard is up.
well, now that we dont have a proven theory on why we dream or what are dreams, what i feel about it might be a valid opinion. dreams are random interpretation and thus vivid images or clips of the bits of memory carrying layers of neurons which usually contribute to a meaningful thoughts and thought process during waking hours with consciousness awake. but when asleep with consciousness not really 'active' still interprete the memories (content) of the same neurons without meaning yet forming clips. randomly they make people 'believe' that they carry message or appear relevant.
Reply | Report Abuse | Link to thisMy dogs use to dream. They bark, run and cry while asleep. So, this might be something most mammals have wired in their brains.
Reply | Report Abuse | Link to thistheories are surmises by brilliant thinkers. every one of them seem credible. while awake and doing a thing, i often go back and see clearly scenes over the many many years. and also construct the future episodes i am planning. when sleep takes over from my dozing self or deprived mind the many other areas of my brain still keep working at a lower level. on sudden jolt up from a dream i often remember and more often donot, what i was dreaming. each brain cell has been occupied by the various memory molecules of different incident in my life. these come to play during the restful phases of sleep. i do hear the bells and sounds, and smell nice things sometimes, and the touch feelings quite often. it is taste that i havent. in deep dream state when my alarm bell goes and i dont wake up i am dreaming 0f some ringing cycle bell or such as if in a split second my brain has cooked up a story prior to the ringing of the bell.# there must be surely experiments on a sleeping brain cortex areas being stimulated by electrodes, or MRI studies of the activities of the areas during dreams ? enigmatic dreams like that of the pharao?
Reply | Report Abuse | Link to thisquite nice roy
Reply | Report Abuse | Link to thisyes lilian bits of memory.....
Reply | Report Abuse | Link to thisDreams, in sleep or eyes wide open and heart fluttering, are just fantastic. I have witnessed my cocker spaniel barking in sleep; he must have seen a visual or some complicated scene coded in his sense of smell.
Reply | Report Abuse | Link to thisIt is right no law of the land punishes someone for dreaming weird or nonsense. But its expression can be highly repungent even in close friendship; this again is my latest experience. Dreaming is a mystery for me and for science as well . But subconscious mind has its own ways that leads to some activity in our brain getting into our recent memory which we recollect on waking up. All dreams are not weird; some are extremely lovely and I wait for such experiences always even now after completing 57 years of my happy life.
Neurophysiological study- based evidence suggest that there is a lot of unity in dreaming states and wakeful cognition in respect of thought contents . Only that the dreams are more hallucinatory.That is so because the conscious cognition controls are slowly lessened ,particularly due to lower activation of prefrontal cortical and cingulate regions in brain.At the same time the activation of amygdala indicates that the unconscious becomes more active.Some sort of inner light is falling on the store house of images in mind,and energising the amygdala,which is also the seat of memory and emotions.May be some of the unwanted images are being weeded out in this process ,and some of the relevant ones are reinforced by this activation-inactivation processes.The mind is more relaxed in pure consciousness states where the conscious cognition is less and unconscious mind is more active,due to an absence of cognitive thinking,as empirically verified.This also regenerates the mental functions as reported in literature on consciousness studies and research on cognition and creativity. The amygdala is also the region that controls the breathing through the hypothalamus,which explains the particular breath patterns in sleep.Sleep breathing is more internalised ,and rather the movement is more up-down than in-out,as is the the case in wakeful breathing.Ancient Indian metaphysical literature related to yoga places much importance on breathing techniques like in sleep,when the movement is more internalised,calling it as a special type of pranayama technique to purify and regenerate the mind,as part of spiritual methods for self realization,and knowledge of reality,as truth of Being and self.The world is a dream as some writers have written about,and we can wake up from that dream by becoming our original selves,which is more akin to an extended notion of self.In fact scientific studies have revealed that self as a localised notion differentiating ourselves from the world around is a learnt behaviour,and there is no centre in brain associated with such self notions.At the same time self notions are found to be a disparate system,where as that is not the case with extended self systems which are innate to us,and hard wired into our brain stem cells,connected with the brain circuitry for impulse like actions
Reply | Report Abuse | Link to thisSURESHKUMAR.S,SCIENTIST AND ADVISER,NIIST,TRIVANDRUM,INDIA
Neurophysiological study- based evidence suggest that there is a lot of unity in dreaming states and wakeful cognition in respect of thought contents . Only that the dreams are more hallucinatory.That is so because the conscious cognition controls are slowly lessened ,particularly due to lower activation of prefrontal cortical and cingulate regions in brain.At the same time the activation of amygdala indicates that the unconscious becomes more active.Some sort of inner light is falling on the store house of images in mind,and energising the amygdala,which is also the seat of memory and emotions.May be some of the unwanted images are being weeded out in this process ,and some of the relevant ones are reinforced by this activation-inactivation processes.The mind is more relaxed in pure consciousness states where the conscious cognition is less and unconscious mind is more active,due to an absence of cognitive thinking,as empirically verified.This also regenerates the mental functions as reported in literature on consciousness studies and research on cognition and creativity. The amygdala is also the region that controls the breathing through the hypothalamus,which explains the particular breath patterns in sleep.Sleep breathing is more internalised ,and rather the movement is more up-down than in-out,as is the the case in wakeful breathing.Ancient Indian metaphysical literature related to yoga places much importance on breathing techniques like in sleep,when the movement is more internalised,calling it as a special type of pranayama technique to purify and regenerate the mind,as part of spiritual methods for self realization,and knowledge of reality,as truth of Being and self.The world is a dream as some writers have written about,and we can wake up from that dream by becoming our original selves,which is more akin to an extended notion of self.In fact scientific studies have revealed that self as a localised notion differentiating ourselves from the world around is a learnt behaviour,and there is no centre in brain associated with such self notions.At the same time self notions are found to be a disparate system,where as that is not the case with extended self systems which are innate to us,and hard wired into our brain stem cells,connected with the brain circuitry for impulse like actions
Reply | Report Abuse | Link to thisSURESHKUMAR.S,SCIENTIST AND ADVISER,NIIST,TRIVANDRUM,INDIA
"- the mind,as part of spiritual methods for self realization,and knowledge of reality,as truth of Being and self.The world is a dream as some writers have written about,and we can wake up from that dream by becoming our original selves - " Sorry, but that's just mythological jibber jabber, and non-dualistic science has found no way to localize such supernatural notions.
Reply | Report Abuse | Link to thisI totally believe in the theory of 'sleeping on it' as it soo does happens at times. Sometimes we get real indications, clues, marks, hints and ideas that answer our life problems in curious ways. Dreams are the only channel through which we get to see our loved ones who have died, and that remains our only connection with them. Dreams are an exquisite phenomenon of nature and a mystery that is complex to be unfolded!
Reply | Report Abuse | Link to thisI totally believe in the theory of 'sleeping on it' as it soo does happens at times. Sometimes we get real indications, clues, marks, hints and ideas that answer our life problems in curious ways. Dreams are the only channel through which we get to see our loved ones who have died, and that remains our only connection with them. Dreams are an exquisite phenomenon of nature and a mystery that is complex to be unfolded!
Reply | Report Abuse | Link to thisI have yet to see a thorough list of typical dream attributes, such as:
Reply | Report Abuse | Link to this(1) it is common for objects in dreams to be blends of two or more actual objects, and especially for people in dreams to be a blend of two or more actual individuals.
(2) In waking hours, there is the sense that we are consciously monitoring and controlling our attention, but during dreaming there is no such control and attention wanders at random, sometimes partially directed by problems that have been of concern during the day.
(3) Logical associations commonly exist between elements in a dream, but the dream world permits co-existence of elements that lack associations, and that lack would typically censor the dream scenario during waking hours. Example: "On a floating barge in the sea trying to get to some other country" - the association between a barge and the sea makes sense, as does the association between being on a boat at sea and trying to get to another country. But one would not generally travel on a barge, and that lack of association would generally stop the person from combining those elements (barge, travelling) when awake.
I agree with djohnsonphysics that artificial neural networks should be looked at to shed light on dreaming. I remember reading about a network that was trained to recognize digits and letters, and when presented with a fuzzy image that was sort of halfway between a particular digit and letter, the network output was a blend of that digit and letter. Neural networks seem to naturally produce the blending of elements that we often see in dreams, and the lack of conscious control of attention and lack of censuring of incompatible elements allows such blends to appear during dreaming when they wouldn't during waking hours.
I find all of your comments very interesting. My mother suffered from Alzheimer's Disease and dreams seemed to play a prominent part in it. She constantly complained of fatigue and felt that if she could only dream, she would feel better. On the other hand, she was very often confused as to what was real and what wasn't. She would ask me if she was dreaming and if I was seeing the same thing that she was. I've often wondered how much dreams, or the lack of them, play a part in dementia. Toward the end of her life, she was not sleeping at all so I can only speculate on the horror that she suffered.
Reply | Report Abuse | Link to thisThis subject is so very interesting and intriguing, especially since we all dream and have our own opinions on how and why dreaming originated even if they come from a much less educated individual. It seems to me that dreaming is the way our subconscious communicates with our consciousness using symbols that can be used to associate with an emotion such as fear, sorrow, and love, as well as, alternate solutions for a problem or dilemma. It's like two separate individuals living in the same body, having the same experiences but the only way they can talk is during sleep. However one wants to define the subconscious, I believe it is a very powerful part of our essence interacting with us all the time, awake or not, but through dreams the interaction we experience is visually vivid and is acknowledged in terms we understand. Our consciousness deals with all tangible realities but the subconsious sees everything from a different and unique point of view. My dreams, when I remember them, are almost always in places I've never been and people I don't know.
Reply | Report Abuse | Link to thisTo my fellow dreamers :
Reply | Report Abuse | Link to thisOur minds most likely dream while we sleep, because they have nothing better to do. They simply get bored and begin to play out scenes from our memories.
PJM
mcleanp@navcanada.ca
Lets assume there exists a neural mechanism (lets call it the New-Memory Incorporator, NMI) whose job it is to incorporate new information into long-term memory. The NMI would likely follow a procedure that first locates a suitable region and then selects a group of neurons to be a home for each new memory.
Reply | Report Abuse | Link to thisI think it fair to assume that there wont always be a crop of mature, unused neurons lying around waiting for the next memory, so the new memory will have to be laid down using any unused mature neurons along with neurons already being used to store existing memories.
In assembling a particular group of neurons for the new memory, the NMI would disturb, jostle, or awaken existing memories or portions of existing memories. While these memories are being jostled to accommodate a new memory, they would be read by the same neural mechanism that does that same job for the brain during waking hours, i.e. retrieving information from memory.
But instead of reading a whole memory, as it would when the creature is awake, the RM reads the fragments of the jostled existing memories - perhaps dozens or hundreds of fragments - which it then stitches together into a kind of loose, unstructured sequence.
When presented to the brain (whose owner is asleep), the sequence is perceived by the brain to be regular input which then, in some cases, stores it in short- or medium-term memory.
When we awake, we become aware of the stored sequence and generally recognize it as the stuff of dreams. Depending on its emotional impact, the sequence either fades or becomes incorporated into long-term memory. Some dreams we remember for long periods of time. I suspect that such long-lasting dreams, or fragments of dreams, might be the result of random variations in the operating characteristics of the NMI; perhaps it occasionally gets overzealous.
Dreams, then, are the result of the process that selects groups of neurons as a home for a new memory and are thus a by-product of regular neurological activity. In this scenario, dreams dont seem to offer a survival benefit nor do they impose a cost - other than, from time to time, some emotional stress, or in some cases, apparent epiphanies. But this is an assumption; they may serve some ancient function that remains beyond our ken.
Recurring dreams would happen if the NMI, while making its rounds to assemble groups of neurons for new memories, regularly visits (for reasons unknown) the same group of neurons and jostles the same group of existing memories and stitches together a sequence identical to that produced on the previous visit; a recurring sequence yields a recurring dream.
When fragments of existing memories are assembled, stitched together, and presented to the brain as regular input, the resulting dream would generally be pretty bizarre. --JGP
The above is purely speculative with little relevance to the meaning we sense in our dreams, and the similarity to day dreaming, wishful thinking, desire to forget or alter mistakes, etc., etc.
Reply | Report Abuse | Link to thisIt seems like a serious stretch to think that something that goes on in your head while you're just laying there can have any sort of effect on attracting a mate. Dreams are not peacock feathers.
Reply | Report Abuse | Link to thisI view dreaming as a balancing mechanism. In non-rem sleep , the sense of self disappears. The purpose of dreaming is to generate a strong sense of self to counterbalance the earlier loss of self. This also explains why dreaming is so often associated with fears and threats - since these emotions strenghten the sense of self.
Reply | Report Abuse | Link to thisSriram
The usual content of my dreams is not threatening or related in any obvious way to what I'm experiencing in my life. They are extremely interesting situations such as finding a part of my small city that I did't know existed, or flying above a street between buildings in a big plane, or trying to get to the airport in time (flying-related dreams are common with me), or floating in midair in a large room watching people below. When I wake I sometimes can almost but not quite recall a dream that just ended, as if the dream departed my memory but its ghost remained. I find dream content fascinating but I have no idea why it is one thing and not another.
Reply | Report Abuse | Link to thisWhy does dreaming have to be an adaptation? Why not a byproduct of our neural network? Regardless, how could evolution help explain the meaning of a particular dream and its significance to a particular individual?
Reply | Report Abuse | Link to thisWhy should dreams be considered an adaptation at all? Why not a simple byproduct of our neural networking? Regarless, how can evolution contribute to a theory regarding the meaning of dreams, to explain the meaning of a particular dream for particular person?
Reply | Report Abuse | Link to thisIn the context of an evolution-based theory, a more fundamental question is why do we sleep? And then one might ask, do we sleep because we need to dream? Or is dreaming an independent phenomenon within sleeping? All of which points to how little we know-evolution or no-of mind, and its principal apparatus, brain.
Reply | Report Abuse | Link to thisMany times I have felt that a dream takes on meaning as I awaken: the dream is a muddled jumble of random neuron firing, and the conscous mind forms a coherant, if often irrational pattern.
Reply | Report Abuse | Link to thisBefore starting CPAP theraphy, I had vivid and detailed dreams, usually appearing scripted with a bit of weird thrown in. I was suffering severe hypoxia: With CPAP, the dreams ceased.
I believe dreams are a jumble of random images that are edited to a coherent if bizzare pattern on awakening. I suffered from severe hypoxia due to sleep apnea. I had very detailed and vividly colored dreams, seemingly scripted, with incongruent images, for example, dinner-plate black widow spiders in an outhouse marked, not with an hourglass, but the old Nippon Electric Company "NEC" logo in red. After starting CPAP theraphy, the dreams stopped cold.
Reply | Report Abuse | Link to thisThe "order upon awakening" hypothesis is compatible with most, if not all, explanations of dreaming: it is not our dreams we remember, but our rationalization of chaos.
I have noticed a reoccurring pattern in my own life in that when I am learning a new thing such as a new programming language or attempting to create a complex design, I will start having dreams about the subject, with associated non sequiturs, about 3 days into to process. Another issue I would point out is that other animals dream. Any person with a dog will at some time notice their dog dreaming. Mine would occasionally run in her sleep. Any theory of dreaming would also need to address this more general case.
Reply | Report Abuse | Link to thisI see many interesting ideas in this discussion, and I believe that there are likely to be several reasons that we dream. However none of these ideas explain some of my own experiences. The most troubling is a series of dreams that I had at least 6 or 8 times over a period of decades. It was always the same dream, but was not a particularly vivid or meaningful dream, except that I had a feeling of deja vu during the dream. Each time I dreamed it, the feeling of deja vu was stronger, until finally it was overwhelming. Then one day I was awake and going about my business when I realized that the events in the dream were starting in real life, including the powerful feeling of deja vu. The whole sequence lasted a long time, perhaps a minute, and I knew exactly what was going to happen next at every step. In a nutshell, I had a repetitive dream that came true in every detail.
Reply | Report Abuse | Link to thisAs a result of this experience and others like it I have started asking other people whether they have ever had an experience that could not have happened according to their own understanding of the laws of physics, such as a dream that came true. More often than not they say yes. Even some hard-core mechanistic physicists have admitted to me that something happened to them that they believe was a violation of the laws of physics. Anecdotes like this don't prove anything by themselves, but perhaps we should not be too quick to dismiss theories that are "irreconcilable with a Darwinian framework," and worry about reconciling them with Darwinism after we figure out how the brain works.
My question to you is this: Do we relate the material, subjects and topics we dream about with our very own daily experience or to some influence from beyond? To answer this question I have been traying to talk to somebody "Blind from birth". Do people "Blind from Birth dream? And if they dream what do they dream about? If somebody have an answer to my question pls. contact me at arrpla@yahoo.com. Thanks.
Reply | Report Abuse | Link to thisWhen I was seven years old I had heat-stroke. While recovering from it I contacted every childhood desease, most likely due to a immune systeme break down. After one year in bed and learning to stand and walk again, I had severe headaches, and was taking pills prescribed in the mid 1930ties for it. Since they did not seem to work I threw a violent temper tantrum, and refused to take any more of the medication. And the headaches disappeared, and I have not had another one since than. In 1937 I used to have nightmares and they disappeared and only seem to start now, at age 80,to come back again as dreams I can not remember.
Reply | Report Abuse | Link to thisAlso since 1937 no noise could wake me up,and that includes gun shots. I had to be touched to wake up, and then was instantly wide awake. I also did only about 4 hrs per 24 hour period. Now I sleep about 7 hrs in the same period.
Perhaps dreams are some form of temporal Spirit-mind transportation to an as yet undiscovered parallel existence, similar to reported out-of-body experiences or alleged near-death experiences of travelling down a temporal wormhole. Maybe what we dream is in fact real from which most of us are returned without harm or lasting memory? Who is there to deny what curved space-time can do to our electrical senses?
Reply | Report Abuse | Link to thisIt should be born in mind when considering the evolutionary aspects of dreaming, that it is not, of course, just humans that dream. Dogs and cats and - perhaps - all other mammals dream. There must, therefore, be some general evolutionary advantage to dreaming.
Reply | Report Abuse | Link to thisI think it should also be born in mind that we have more than one type of dream, and that different types of dreams may require different treatment and explanations. For example, some dreams are clearly rooted in everyday life. Others are completely ficticious or hallucinatory. Some have clear narratives, while others seem arbitary and confused.
As a normal dreaming person for many years, I have found most dreams to be logical and meaningful (no superhuman or supernatural stuff). It is also often very relaxing, except the tragic and nightmarish ones. Sadly, we forget most of what we dream. One can do all kinds of studies but what has been most baffling for me is that how while we are sleeping, the mind is able to craft a story on its own including giving voice, dialogues and body language to characters. In fact, most such stories are fresh and have not happened earlier in real life. There is also probably some connection between our state of mind, stage of life and the stories in the dreams.
Reply | Report Abuse | Link to thisI think our bodies are just like some of the machine that we run today some of them stay plug in all day with power of , but it s still on put if we unplug it . It will loose all of its info and crash
Reply | Report Abuse | Link to thisDreams are nothing but our mind's natural tendency to wander about in order to probe the unknown through what we already know. This happens every moment whenever the brain gets free from engagements with sensory organs. We call that wandering as 'day-dreaming'.
Reply | Report Abuse | Link to thisWhile in sleep, it often happens that body goes to take rest while the brain does not want it so wanders randomly here and there like day dreaming with the same purpose of probing the unknown. This process is explained here -
http://theosoph-universeofmind.blogspot.com/2009/12/accessing-unknown-through-imaginations.html
I'm not convinced of the various attempts in this article to squeeze dreaming into one or other theoretical box labelled "adapted for...", though the memory and experience sorting and purging seems to make most sense. My dog dreams, apparently of fighting, snarling and chasing things, to judge by her muffled woofing, whining, twitching feet, eyes and nose, when she's asleep. These are important experiences in her waking life, so I guess she needs to sort it all out too. When I ask her to describe the experience she just shakes herself and scratches the door to be let out.
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Reply | Report Abuse | Link to thisHi, AnonInTexas
My mother also sufferred the last 10 years of her live with Alzheimer's disease. That was amazing that your mother had the awareness to ask you if she was dreaming or not. She must had been in the early stages at that point. As far as dreaming, as I am taking an online graduate course discussing the biopsychology of sleep. I had a dream last night that my husband, son and I were energies hovering over a large 'black pearl' looking ship as they were circling around an area only to locate a ramp to an underworld that would allow them to escape their terrible situation they were facing in the black vast ocean. The crue members on the ship I think were my husband, my son and myself. This is an example of how the problem-du-jeur can be solved through dreaming. We are experiencing some terrible personal situations with a possible solution that is found, but is hard to get. Similar to the ship searching for the hidden ramp leading to the underworld. The phrase, Sleep on it! has validity there have been many times I have not been able to answer tough questions, but after a good night sleep, the next day my answer is very clear. Also there was a study mentioned in this article about an assignment that was given to a student who went home frustrated. After a good night sleep, the answer came to him. The assigment was, What is the next letter in the series of the following letters, OTTFFS? The answer is S. as O=one, T=two, T=three, F=four, F=five, S=six, and S=seven.
To answer your question regarding how the dreaming and sleep plays a part in dementia? Sleep allows the body to produce serotonin in the brain, which is the good feeling hormone. If your mother was not sleeping toward the end of her life, that would say to me that she could have suffered from a lack of sleep. There is a saying that no one ever died from a lack of sleep. I don't know how that became true, as a lack of sleep can surely cause much distress in one's life, possibly to death, through sheer madness. Those suffering from dementia, I have noticed have rough sleeping patterns, as they wake up many times throughout the night. You have brought up a very interesting question. Once I finish my assignment on sleep and dreaming, I will send you another post.
Your friend (another suffering daughter of parent with Alzheimer's disease)
It's OK to brush off ooga-booga Jungian spiritual stuff, but these cats are chimpanzees compared to Freud. Their theories are so incredibly lame!
Reply | Report Abuse | Link to thisAs for problem solving, that is nothing more than a convenient side benefit of unconscious wish fulfillment. It was Alfred Adler who first proposed that the function of dreams is to face problems one is uwilling to face during the day. Does anyone take Adler seriously anymore? He is as forgotten as the evolutionary psychololgists are about to become.
I am surprised that the article doesn't bring up the effects of sleep starvation, which include hallucinations and thermoregulatory problems (i.e. the brain gives itself fevers and hypothermia). These things are not necessarily linked to dreaming, but it seems likely to me that they are. It is mentioned that REM sleep is a period of thermoregulatory shutdown, and it is also linked to dreaming.
Reply | Report Abuse | Link to thisOh,and in response to renee:
Reply | Report Abuse | Link to thisI didn't know of any saying about "no one ever died from a lack of sleep". I would say that saying is about as true as "no one ever died of AIDS" (recall that AIDS just makes it easy for other bugs to kill you). As you pointed out, there are psychological effects, but the physical effects can be quite damaging, in both chronic low level sleep deprivation (greater risk for heart attacks, etc) and acute sleep starvation (immune system weakening, thermoregulatory problems)
Freud's wish fulfillment theory is discredited only by people who don't understand it. Wish fulfillment isn't a function of dreams. It's only a means to accomplish the function. According to Freud, the function of dreams is to protect sleep. In other words, dreams are useful to the organism. They are a survival factor in evolution. Freud's theory is a wee bit superior to any reductionist neurological theory presented here I think.
Reply | Report Abuse | Link to thisOne more thought: All psychoanalysis is based on Freud's dream theory. This includes all the branches of Kleinian, Lacanian, Kahutian, etc. All the object relationists and ego psychologists buy into it. If it turns out that Freud's dream theory is wrong, a whole branch of medicine will cease to exist.