Dreams and Memories

 By : Ariyanto Yanwar, M.Psych., Psychologist

There are three kinds of memories : sensory memory, short-term memory, and long-term memory. Sensory memory is the quickest to fade, long-term memory may last as long as life itself, while short-term memory, called working memory, last from seconds to a few minutes. The incoming information or stimulus is first held in sensory memory. With attention, it is then passed into working memory for processing, then with rehearsal, it moves into long-term memory (Zhang, 2004).

Temporary memory is limited and memories are stored in stable form. It serves as a fast data storage, rather than permanent data storage like long-term memory storage. There are two kinds of temporary memory stores : declarative and procedural memory. Declarative memories are types of memories that can be consciously recalled such as facts and knowledge. Procedural memoris are a types of memories that tell us how we do things, procedure, or the steps we need in order to do a certain task (in Zhang, 2004). Information from the working memory will stay in the temporary memory until it’s either deleted or moved into long-term memory. Because of its limitation, it can overload and must be cleared periodically (Zhang, 2004). Our waking brain can’t do this since it’s busy processing large amount of information while we’re awake. The function of sleep is believed to process the data saved in the temporary memory, encode it, and move it into long-term memory. This includes comparing new informations with old ones inside the long-term memory to identify, and if acceptable, delete unwanted items (Zhang, 2004).

What Does the Brain Do While We’re Sleeping?

Recently, it has been confirmed that rather than being passively reactive, the brain and nervous system are spontaneoudly active even when we’re sleeping. Even when we’re asleep and unconscious, our minds don’t get to rest. The brain reduces its activity, yes, but it’s still aware to the stimulus of the surroundings (Breger, 1967).

While we’re awake, sensory memory continuously receives information from all five sense. The information first enters the sensory memory, with a little more attention, some of the information will be moved into working memory to be processed. The brain will pull out existing memoried inside temporary memory or long-term memory in search for any relations with the incoming information. In general, all information processed in working memory will enter the temporary memory. While we’re awake, the long-term memory is in retrieval-only mode, which makes it unable to receive new information (Zhang 2004).

While we’re sleeping, however, all five senses are slowed, blocking external arousal. Without external disturbances from the environment, working memory will process data transfer, comparing it with data retrieved from temporary memory, compare it with the ones in long-term memory, delete, duplicate, and replace datas inside the brain – Housekeeping Process. In this period of time, temporary memory is in retrieval-only mode, that’s why any brain activities, such as dreams cannot be recorder into the temporary memory. The only memory store that can record brain activity in this period is the short-term/working memory store (Zhang, 2004). This process can be disrupted by several reasons. One of them is Sleep Deprivation. Without enough sleep, the housekeeping process cannot work properly, therefore, disturbing the entire cognitive process, resulting inability to concentrate or it becomes harder for the person to memorize ore remember something Zhang, 2004).

Dreams

Dreams occur in the third stage of sleep states, the REM (Rapid Eye Movement) sleep, which has been proven as a biological state found in all mammals (Breger, 1967). The name comes from the (Lahey, 2004). Aserinsky (1952) was interested in this after noticing slow, rolling movements of the eyes that occured when an infant was asleep. He then straped the child to an EEG (Electoencephalograph) and Aserinsky saw that the infant’s brain activity was no different from when he was awake. This REM stage can occur more than once at one night of sleeping, and everytime it did, the same brain pattern in the child resembling wakefulness returned. And when Aserinsky woke the subjects when they’re showing eye movements, most of the subjects reported that they were dreaming when he woke them (Lahey, 2004). Not only the brain, the autonomic nervous systems and other parts of peripheral nervous system are also getting busy while dreaming resulting in increased blood flow, irregular heartbeat, face muscles and fingers twitching, and irregular breathing (Lahey, 2004).

Researchers believed that dreams were uncommon during non-REM phase of sleep cycle. However, dreams don’t only occur at REM sleep. Though not as much as REM sleep, dreams can also occur in Non-REM sleep stages. The nature of the dreams inside non-REM phase is quite different from that of REM dreams. But when both REM and Non-REM dreams are considered, we spend a surprising amount of time dreaming (Lahey, 2004). Kahan (1994) in Tarnow (2003) finds that 60% people are completely unaware of dreaming while in a dream, and that 46 % are completely unaware of controlling any aspect of the dream experience.

Everyone of us dream. But there is an incredible variation of subjective dreams experience (Hall & Van de Castle. 1966 in Franklin & Zyphur, 2007) . Some people remember their dreams, some don’t, but not often is the case where someone can remember completely what they dreamt about. While others experiences vivid dreams with perfect visual and emotional content, some dreams appear without any script. It just randomly jump from scene to scene and don’t seem to make any sense. Some have full control of their dreams, while others appear to be a bystander, or merely following the script. With so much varieties of dreams, it’s easy to see that dreams have personal traits and contain different elements on each person, therefore, can mean differently even when they appear to be similar (Potter, 1996 in Franklin & Zyphur, 2007). Other than being described as “fragmented and Bizarre”, dreams are also considered as creative (Payne & Nadel, 2004).

Zhang (2004) proposes two types of dreams as the result of mental activity going on in the brain. Type I dream, a thought like mentation, is the result of memories being replayed when declarative memory data is retrieved from temporary memory store during NREM sleep. Type II dream, a more dream-like mentation, often occurs during REM sleep when procedural memory is being transfered from temporar memory to long-term memory. Type II and REM have no direct causality, in fact, they’re two different states. Seems like type II dream occurs when no attended conscious data stream flows into the conscious subsidiary system of working memory. From this point of view, although it occurs most often in REM sleep, the type II dream can also occur in any other state, including NREM sleep and even waking state (in Zhang, 2004).

Freud (1900) in Tarnow (2003) mentioned that perceptions and thoughts that an individual experienced during his waking life, could more or less disturb his unconscious. The unconscious is mostly filled with “ego” drives and those are being contained inside the unconscious mind by defense mechanisms. When a person is sleeping and dreaming, the defense mechanisms are lifted and leaving only censor to scramble his unconscious expressions. Our repressed desires, our “ego” drives will appear inside the dreams, may it be direct expressions, or converted into symbols. The censor transformation is called “Dream Work” and Freud divided it into condensation, displacement, visual images, and secondary revision. Freud believed that by interpretating dreams, a person’s unconscious mind, which is an important source of his personality, can be revealed (Tarnow, 2003). Tarnow (2003) interpreted Freud’s “unconscious” concept as LTMS or Long Term Memory Structure and this serves as a large memory storage. Perceptions and thoughts that are already there in the first place are recalled and are converted by the Dream Work into something to match with current perceptions and thoughts to construct an acceptable recall. These converted memories often appeared as dreams. Freud, however did not succed telling if the Dream work took place before or after dreaming. This process doesn’t necessarily have to happen one at a time. Sometimes a number of different and sometimes unrelated memories are joint and converted together into a dream. This is perhaps one of the reason why dreams sometimes don’t make any sense. Tarnow (2003) also mentioned that meaningful memories or memories with strong emotional traits are easier to recall. Freud in tarnow (2003) also wrote that all the contents inside the dream come from thoughts and perceptions of the day before the dream. This has been proven by statistics, but it is also proved that contents of a dream are also drawn from events as far back as more than a year.

Freud’s original theory is that dream is “A structural formulation leads to a conception of the dream as one output of particular memory systems, potentiated by emotional feedback, and operating under the guidance of programs that are peculiar to sleep” (from Breger, 1967). Freud (1900) in his book, The Interpretation of Dreams mentioned the functions of dreaming. The first is to defend the mind from external stimulation, therefore, protecting the dreamer. But the main job of dreams are to protect us against threatening internal impulses from the unconscious mind. The mind transform our threatening impulses or desires into something more acceptable, and often times, dreams serve as “wish fulfillments.” Therefore, dreams are the mind’s effort to “discharge” threatening impulses, and the Dream Work converts it into something more non-threatening and acceptable (in Breger, 1967).

 

Dreams Contents and It’s Connections to Memory

Hall (1951) as well as Strauch & Meier (1996) mentioned that :

“Most of the conscious experience in dreams is visual. Only about one-fourth of dream images include auditory sensations, and about 20% include body sensations. About half of the dreams that involve body sensations are sexual – 10% of all dreams. Less than 1% of dreams include tastes or smells.”

The characters inside dreams are most likely the people we know. With ourselves as the main character, of course. The faces that occur inside our dreams are not random. Research has found that all the faces inside our dreams are real people. We might not know them at all, but at some point in our life, we crossed paths with them and we stored their faces inside our unconscious mind. It could be a woman we met eyes with for a very brief moment inside the mall, or even the conductor inside the train we rode for the first and the last time. We have seen all those faces but failed to recognize them, and they can sometimes occur inside our dreams (Lahey, 2004).

Most of the parts of the contents of our dreams are directly related to things that are going on in our waking lives. This is called “Day Residue” by Sigmund Freud. Day residues are memories of recent events that may appear inside a dream. This may consist the people involved, the place, the situation of the event, objects, or even a complete re-enact of the event. It can also contain strong emotional feelings like intense worries or happiness (Breger, 1987). The dreams at night should contain at least one character or event from the day, or the week before, or even earlier in some part of the dreamer’s life (Lahey, 2004). Still, this is not more than what appears to be the content of the dream. Freud believed that if explored more, the dream has more meaning to it that what appeared on the outside.

One experiment conducted by Lauer, Riemann, Lund, & Berger (1987) at the Max Planck Institute of Psychiatry in Munich, Germany. Participants were shown either a neutral film or an upsetting film depicting violence, humiliation, and despair at different nights. They were awaken at the first REM sleep and reported their dreams included considerably more aggressive and anxious content than on the night following the neutral film. And more, the dreams also contained images or themes related to the content of the film (in Lahey, 2004).

Sometimes the real-world event that appeared in the dream is something that’s happening while we’re asleep. Take an example, a dream that somehow includes the telephone or the alarm clock ringing at the time. This phenomenon is called “Stimulus Incorporation”, where the stimulus from the real world is directly incorporated into the dream, and sometimes converted into other forms (Strauch & Meier, 1996 in Lahey, 2004).

 

Why Are Dreams So Weird?

Baylor & Cavallero (2001) in Payne & Nadel (2004) found that episodic memories inside the dreams are rare and oftenly difficult to relate to the events from waking life. These fragmented dreams inside REM sleep often have bizzare content that most of the time don’t make any sense. In REM sleep, dream state, it is possible to fly, walk through walls, or even talk to a fictional character. NREM dreams, however, do contain episodic memories dominantly, but remote memories can blend in occasionally (Payne & Nadel, 2004).

Some of the contents of our dreams simply reflect the events and concerns of daily life. On some cases, a person can litterally re-enact something he or she had gone through before. But it should be remembered that the contents of our dreams aren’t just real life experiences. Sometimes they might consists of bizarre images or fictional-unlogic story lines and most of the times, they seem to be meaningless. But as Freud mentioned before, the contents of our dreams oftenly describe our personality, our desires, and random things inside the dream might be on to something. Freud divided the contents of dreams into two levels : manifest and latent. The events that occur inside a dream is manifest content, while the true meaning behind those events is latent content. For example, a woman dreamt she was riding a train and became frightened as the train entered a dark tunnel. Freud might see the manifest content, the train and the tunnel, train as a penis, and the tunnel, a vagina, hence the latent content of the dream might concern the woman’s conflicts about having sex with a man. Though researchers argued Freud’s dream interpretations as inaccurate, cause symbols can be interpretated in many ways depending on the person, and the situation (In Lahey, 2004).

Taylor (1983) proposed two simple basic principles about dreams – (1) dreamers are the only one who could understand the least bit what their dreams are about. (2) Dreams don’t only have one layer, it means the dreams might seem like something, but there must be something else under the ones on the surface.

Why We Forget Our Dreams

            We all sleep, we all dream, but often times we woke up unable to recollect the dreams we had even though it felt so clear when we were sleeping. We can seldom recollect more than a few minutes worth of our dreams after waking. We can remember the dream as soon as we woke up, but after a moment, it becomes hazy and after a period, we can completely forget the entire dream and won’t even remember we ever had that dream. The reason to this, as shown before, we forget dreams because our temporary memory store is switched into retrieval-only mode for memory processing when we’re asleep. Any brain activity during this period cannot be saved. Only short-term memory store is available but since it has very limited capacity, the memories will decay rapidly and replaced with new information. This explain why one can remember very little of their dreams (Zhang, 2004).

Conclusion

            Even when we are asleep, our minds don’t stop completely. The activity of the brain might be reduced significantly but there are still important activities going on inside our brain when we are asleep. One of the activities is the Housekeeping Process. The memory from the temporary storage are being processed and compared to long-term memories to find out which ones can be kept, and which ones have to go. The memory flow from this process creates brain activity, therefore resulting what we call as dreams. Dreams reflect activity in brain structures concerned with processing, storing, and representing recent experiences. Dreams also can sometimes give us the chance to re-live the experiences we have been through, the knowledges we already had, and the memories whe have been building up all our lives.

            Though the contents of dreams may be hazy, random, and most of the times, don’t make any sense, it is believed that dreams represent our waking life in some way. When we feel a strong emotion in our waking life, that feeling might enter our dreams, may it be pleasant or an unpleasant feeling. The fears, the anger, or the worries we have in our waking lives, can affect the contents of our dreams. It may come as a whole re-enact of the situation, it may also come as fragments, or symbols. Unpleasant feelings, or deeply troubling emotions like traumas are potentially harmful to the dreamer, that’s why the brain has its own defense mechanism to “hide” the memories of that particular feeling into something less threatening. As an example, Freud mentioned water in a dream represent “replenish”, that the dreamers are overwhelmed by problems and need to relax. However, this symbolism holds little validity, cause there are differences in people personality and life experiences, so one symbol can be interpreted into an entirely different objects or expereiences depending on who has that particular dream. The nature of dreams are personal, that’s why Freud’s interpretation is unacceptable by the researchers in his days. Freud also says that dreams reflect our inner desires. Something like a defense mechanism to protect our minds from threatening impulses, the “ego”. Dreams serve as a tool to express this impulse in a safe and acceptable way.  One of the terms of memory is “repressed memories”. In order to defend itself from trauma or overwhelming emotional experiences, the mind then “hides” the traumatic memories the memories of those events and store it away from our conscious awareness. Later in life, after the mind is better able to cope with those memories, the memories would emerge into consciouness. It doesn’t have to happen all at once, but it can also appear in “memory flashes”, Deja vu’s, or as dreams.

            In conclusion, dreams are not random. If researched more accurately, each person’s dreams can tell a lot about him/herself. Because dreams are mainly derived from one’s memory, the contents must be closely related to one’s personal life. By understanding where do one’s dreams come from and its significants into his/her waking life, this might help the dreamer to understand his/her unconscious state of mind better.

 

 

 

 

 

 

 

 

 

 

Refferences

 

Breger, L. (1967). Function of Dreams. Journal of Abnormal Psychology Monograph, 72(5). Diunduh dari  www.psychbytes.com/Invisible/Function.pdf   Pada tanggal 17 October 2011.

 

Franklin, M. S. & Zyphur, M. J. (2007). The Role of Dreams in the Evolution of the Human Mind. Evolutionary Psychology, 3. Diunduh dari  www.epjournal.net/filestore/ep035978.pdf  pada tanggal 17 October 2011.

 

Lahey, B. B. (2004).  Psychology : an introduction (8^th Ed.). United States : McGraw Hill. 

Payne, J.D. & Nadel, L. (2004). Sleep, Dreams, and Memory Consolidation : The role of the stress hormone corticol. Learning Memory, 11. Diunduh dari  learnmem.cshlp.org/content/11/6/671.full   pada tanggal 17 October 2011.

Tarnow, E. (2003). How dreams and Memory May Be Related. Neuro-Psychoanalysis, 5(2). Diunduh dari cogprints.org/2068/ pada tanggal 17 October 2011.

Zhang, J.(2004). Memory Process and the Function of Sleep. Journal of Theoretics, 6(6). Diunduh dari www.journaloftheoretics.com/Articles/6-6/Zhang.pdf pada tanggal 17 October 2011.