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Have you ever wondered how you manage to remember information for a test? The ability to create new memories, store them for periods of time and recall them when they are needed allows us to learn and interact with the world around us. The study of human memory has been a subject of science and philosophy for thousands of years and has become one of the major topics of interest within cognitive psychology. But what exactly is memory? How are memories formed? The following overview offers a brief look at what memory is, how it works and how it is organized. What is Memory? Memory refers to the processes that are used to acquire, store, retain and later retrieve information. There are three major processes involved in memory: encoding, storage and retrieval. In order to form new memories, information must be changed into a usable form, which occurs through the process known as encoding. Once information has been successfully encoded, it must be stored in memory for later use. Much of this stored memory lies outside of our awareness most of the time, except when we actually need to use it. The retrieval process allows us to bring stored memories into conscious awareness. The Stage Model of Memory While several different models of memory have been proposed, the stage model of memory is often used to explain the basic structure and function of memory. Initially proposed in 1968 by Atkinson and Shiffrin, this theory outlines three separate stages of memory: sensory memory, short-term (working) memory and long-term memory. Sensory Memory Sensory memory is the earliest stage of memory. During this stage, sensory information from the environment is stored for a very brief period of time, generally for no longer than a half-second for visual information and 3 or 4 seconds for auditory information. We attend to only certain aspects of this sensory memory, allowing some of this information to pass into the next stage - short-term memory. Short-Term Memory Short-term memory, also known as active memory, is the information we are currently aware of or thinking about. In Freudian psychology, this memory would be referred to as the conscious mind. Paying attention to sensory memories generates the information in short-term memory. Most of the information stored in active memory will be stored for approximately 20 to 30 seconds. While many of our short-term memories are quickly forgotten, attending to this information allows it to continue on the next stage - long-term memory. Long-Term Memory Long-term memory refers to the continuing storage of information. In Freudian psychology, long-term memory would be call the preconscious and unconscious. This information is largely outside of our awareness, but can be called into working memory to be used when needed. Some of this information is fairly easy to recall, while other memories are much more difficult to access. The Organization of Memory The ability to access and retrieve information from long-term memory allows us to actually use these memories to make decisions, interact with others, and solve problems. But how is information organized in memory? The specific way information is organized in long-term memory is not well understood, but researchers do know that these memories are arranged in groups. Clustering is used to organize related information into groups. Information that is categorized becomes easier to remember and recall. For example, consider the following group of words: Desk, apple, bookshelf, red, plum, table, green, pineapple, purple, chair, peach, yellow Spend a few seconds reading them, then look away and try to recall and list these words. How did you group the words when you listed them? Most people will list using three different categories: color, furniture and fruit. One way of thinking about memory organization is known as the semantic network model. This model suggests that certain triggers activate associated memories. A memory of a specific place might activate memories about related things that have occurred in that place. For example, thinking about a certain campus building might trigger memories of attending classes, studying and socializing with peers. 10 FACTS ABOUT MEMORY Fun and Fascinating Facts About Human Memory Our memory helps make us who we are. From fondly recollecting childhood events to remembering where we left our keys, memory plays a vital role in every aspect of our lives. It provides us with a sense of self and makes up our continual experience of life. It's easy to think about memory as a mental filing cabinet, storing away bits of information until we need them. In reality, memory is a remarkably complex process that involves numerous parts of the brain. Memories can be vivid and long-lasting, but they are also susceptible to inaccuracies and forgetting. Continue reading to learn more about ten fascinating facts about human memory. The Hippocampus Plays an Important Role In Memory The hippocampus is a region of the brain that is heavily associated with memory. Because of bilateral symmetry in the brain, both hemispheres contain a hippocampus. Image courtesy Wikimedia Commons The hippocampus is a horse-shoe shaped area of the brain that plays an important role in consolidating information from short-term memory into long-term memory. It is part of the limbic system, a system associated with emotions and long-term memories. The hippocampus is involved in such complex processes as forming, organizing and storing memories. Because both sides of the brain are symmetrical, the hippocampus can be found in both hemispheres. If one side of the hippocampus is damaged or destroyed, memory function will remain nearly normal as long as the other side is undamaged. Damage to both sides of the hippocampus can impede the ability to form new memories, known as anterograde amnesia. Functioning of the hippocampus can also decline with age. By the time people reach their 80s, they may have lost as much as 20 percent of the nerve connections in the hippocampus. While not all older adults exhibit this neuron loss, those who do show decreased performance on memory tests. Most Short-Term Memories Are Quickly Forgotten Most short-term memories only last 20 to 30 seconds. Photo by Courtney Icenhour The total capacity of short-term memory is fairly limited. Experts believe that you can hold approximately seven items in short-term memory for about 20 to 30 seconds. This capacity can be stretched somewhat my used memory strategies such as chunking, which involves grouping related information into smaller "chunks." In a famous paper published in 1956, psychologist George Miller suggested that the capacity of short-term memory for storing a list of items was somewhere between five and nine items. Today, many memory experts believe that the true capacity of short-term memory is probably closer to the number four. See this in action for yourself by trying out this short-term memory experiment. Spend two minutes trying to memorize a random list of words, then get a blank piece of paper and try to write down as many of the words that you can remember. Being Tested On Information Actually Helps You Remember It Better Research has found that being tested on material can improve your recall of the information. Photo by Darko Novakovic/iStockPhoto While it may seem like studying and rehearsing information is the best way to ensure that you'll remember it, research have found that being tested on information is actually one of the best ways to improve recall. One study found that students who studied and were then tested had better long-term recall of the materials, even on information that was not covered by the tests. Students who had extra time to study but were not tested had significantly lower recall of the materials. You Can Learn to Improve Your Memory Using tools such as a reminder calendar is one way to improve your memory. Photo by Pawel Kryj Do you ever feel like you are constantly forgetting things or misplacing objects that you use every day? Have you ever found yourself walking into a room only to realize that you can't remember why you went in there? While it might seem like you are doomed to simply tolerate these daily annoyances, researchers have found that you can learn how to improve your memory. A 2005 cover story in the Monitory on Psychology summarized research revealing a number of useful strategies to deal with mild memory loss. These techniques include: Utilizing technology to keep track of information. Tools such as hand-held mobile devices, online reminder calendars and pagers can help people keep track of appointment and other important dates. Taking a "mental picture" can help. Systematically trying to make a mental note of things you often forget (such as where you left your car keys) can help you remember things better. The next time you set your keys down somewhere, take a moment to mentally note where you left them and the other objects that were nearby. Use memorization techniques. Rehearsing information, employing mnemonics and other memorization strategies are perhaps the best ways to overcome minor memory problems. By learning how to use these strategies effectively, you can sidestep the faulty areas of your memory and train your brain to function in new ways. There Are Four Major Reasons Why You Forget Things Forgetting can occur for many reasons, including interference from other memories. Photo by Julia Freeman-Woolpert In order to combat forgetfulness, it is important to understand some of the major reason why we forget things. Elizabeth Loftus, one of the world's most renowned experts on human memory, has identified four major reasons why forgetting occurs. One of the most common explanations is a simple failure to retrieve the information from memory. This often occurs when memories are rarely accessed, causing them to decay over time. Another common cause of forgetting is interference, which involves some memories competing with other memories. For example, imagine that a woman just started a new job as an elementary school teacher. She spends some time learning the names of each of her students, but over the course of the year she finds herself constantly calling one particular girl by the wrong name. Why? Because the girls older sister was in the same class the year before, and the two look remarkably similar. It is the memory of the older sister that makes it so difficult to recall the younger student's name. Other causes of forgetting include failing to store the information in memory in the first place, or even intentionally trying to forget things associated with a troubling or traumatic event. What are some of the major reasons why we forget information? One of today's best known memory researchers, Elizabeth Loftus, has identified four major reasons why people forget: retrieval failure, interference, failure to store and motivated forgetting. 1. Retrieval Failure Have you ever felt like a piece of information has just vanished from memory? Or maybe you know that it's there, you just can't seem to find it. One common cause of forgetting is simply an inability to retrieve a memory. One explanation for why retrieval fails is known as decay theory. According to this theory, a memory trace is created every time a new theory is formed. Decay theory suggests that over time, these memory traces begin to fade and disappear. If information is not retrieved and rehearsed, it will eventually be lost. One problem with this theory, however, is that research has demonstrated that even memories which have not been rehearsed or remembered are remarkably stable in long-term memory. 2. Interferance Another theory known as interference theory suggests that some memories compete and interfere with other memories. When information is very similar to other information that was previously stored in memory, interference is more likely to occur. There are two basic types of interference: Proactive interference is when an old memory makes it more difficult or impossible to remember a new memory. Retroactive interference occurs when new information interferes with your ability to remember previously learned information. 3. Failure to Store We also forget information because it never actually made it into long-term memory. Encoding failures sometimes prevent information from entering long-term memory. In one well-known experiment, researchers asked participants to identify the correct U.S. penny out of a group of incorrect pennies (Nickerson & Adams). Try doing this experiment yourself by attempting to draw a penny from memory, and then compare your results to an actual penny. How well did you do? Chances are that you were able to remember the shape and color , but you probably forgot other minor details. The reason for this is that only details necessary for distinguishing pennies from other coins were encoded into your long-term memory. 4. Motivated Forgetting Sometimes, we may actively work to forget memories, especially those of traumatic or disturbing events or experiences. The two basic forms of motivated forgetting are: suppression, a conscious form of forgetting, and repression, an unconscious form of forgetting. However, the concept of repressed memories is not universally accepted by all psychologists. One of the problems with repressed memories is that it is difficult, if not impossible, to scientifically study whether or not a memory has been repressed. Also note that mental activities such as rehearsal and remembering are important ways of strengthening a memory, and memories of painful or traumatic life events are far less likely to be remembered, discussed or rehearsed. Depictions of Amnesia in Movies Are Usually Inaccurate Amnesia: Not Like it Is in the Movies Photo by Ryan Baxter - http://www.flickr.com/photos/15225700@N06/2427008704 Amnesia is a common plot device in the movies, but these depictions are often wildly inaccurate. For example, how often have you seen a fictional character lose their memory due to a bump on the head only to have their memories magically restored after suffering a second knock to the skull? There are two different types of amnesia: Anterograde amnesia: Involves the loss of the ability to form new memories. Retrograde amnesia: Involves losing the ability to recollect past memories, although the ability to create new memories may remain intact. While most movie depictions of amnesia involve retrograde amnesia, anterograde amnesia is actually far more common. The most famous case of anterograde amnesia was a patient known in the literature as H.M. In 1953, he had brain surgery to help stop the seizures caused by his severe epilepsy. The surgery involved the removal of both hippocampi, the regions of the brain strongly associated with memory. As a result, H.M. was no longer able to form any new long-term memories. Popular movies and television programs tend to depict such memory loss as fairly common, but true cases of complete amnesia about one's past and identity are actually quite rare. Some of the most common causes of amnesia include: Trauma: A physical trauma (such as a car accident) can cause the victim to lose specific memories of the event itself. Emotional trauma such as being a victim of childhood sexual abuse can cause the individual to lose memories of specific situations. Drugs: Certain medications can be used to cause temporary amnesia, particularly during medical procedures. Once the drugs wear off, the individual's memory returns to normal functioning. Scent Can Be a Powerful Memory Trigger The sense of smell can help evoke powerful and vivid memories. Photo by Sandi Hanna Have you ever noticed that a particular scent can bring forth a rush of vivid memories? The smell of cookies baking might remind you of spending time at your grandmother's house when you were a small child. The scent of a particular perfume might remind you of a romantic partner with whom your relationship ended on a sour note. Why does smell seem to act as such a powerful memory trigger? First, the olfactory nerve is located very close to the amygdala, the area of the brain that is connected to the experience of emotion as well as emotional memory. In addition, the olfactory nerve is very close to the hippocampus, with is associated with memory. The actual ability to smell is highly linked to memory. Research has shown that when areas of the brain connected to memory are damaged, the ability to identify smells is actually impaired. In order to identify a scent, you must remember when you've smelled it before and then connect it to visual information that occurred at the same time. According to some research, studying information in the presence of an odor actually the vividness and intensity of that remembered information when you smell that odor again. New Brain Connections Are Created Every Time You Form a Memory Diagram of a synapse. Photo from the Wikimedia Commons Researchers have long believed that changes in brain neurons are associated with the formation of memories. Today, most experts believe that the formation of memory is associated with the strengthening of existing connections or the growth of new connections between neurons. The connections between nerve cells are known as synapses, and they allow information carried in the form of nerve impulses to travel from one neuron to the next. In the human brain, there are trillions of synapses forming a complex and flexible network that allows us to feel, behave and think. It is the changes in the synaptic connections in areas of the brain such as the cerebral cortex and hippocampus that is associated with the learning and retention of new information. In one study conducted by researchers at the New York School of Medicine, researchers were able to observe synapse formation in the brains of genetically engineered mice. What they discovered was that in young mice, the tiny protrusions that sometimes develop into longer spines on the receiving end of neurons grew at a rapid rate. This growth rate coincided with the rapid development of the visual cortex. While many of these tiny protrusions eventually faded with age, many did continue their formation into fully-fledged spines. Lead researcher Wen-Biao Gan explained in an interview with the science website WhyFiles.org, "Our idea was that you actually don't need to make many new synapses and get rid of old ones when you learn, memorize. You just need to modify the strength of the preexisting synapses for short-term learning and memory. However, it's likely that few synapses are made or eliminated to achieve long-term memory." Clearly, maintaining a healthy brain and synapses is critical. Deterioration of synapses due to diseases or neurotoxins is associated with cognitive problems, memory loss, changes in mood and other alterations in brain function. So what can you do to strengthen your synapses? Avoid stress: Research has found that extended exposure to stress can actually interfere with neurotransmitter function. Other studies have found that stress shrinks neurons in the prefrontal cortex and hippocampus. Avoid drugs, alcohol and other neurotoxins: Drug use and excessive alcohol consumption have been linked to synaptic deterioration. Exposure to dangerous chemicals such as heavy metals and pesticides can also cause synaptic loss. Get Plenty of Exercise: Regular physical activity help improve oxygenation of the brain, which is vital for synaptic formation and growth. Stimulate your brain: You've probably heard the old adage "Use it or lose it." Well, it turns out there's a lot of truth to that when it comes to memory. Researchers have found that elderly adults who engage in mentally stimulating activities are less likely to develop dementia and people with higher educational statuses tend to have more synaptic connections in the brain. A Good Night's Sleep May Improve Your Memory Sleep can actually help improve your memory. Photo by Mayr / http://www.flickr.com/photos/mayr/ You have probably heard about many of the reasons to get a good night's sleep. Since the 1960s, researchers have noted the important connection between sleep and memory. In one class experiment conducted in 1994, researchers found that depriving participants of sleep impaired their ability to improve performance on a line identification task. In addition to aiding in memory, sleep also plays and essential role in learning new information. In one study, researchers found that depriving students of sleep after learning a new skill significantly decreased memory of that skill up to three days later. Researchers have found, however, that sleep's influence on procedural memory is much stronger than it is for declarative memory. Procedural memories are those that involve motor and perceptual skills, while declarative memories are those that involve the memorization of facts. "If you're going to be tested on 72 irregular French verbs tomorrow, you might as well stay up late and cram," explained Robert Stickgold, a psychiatry professor at Harvard Medical School, in an article published in the APA's Monitor on Psychology. "But if they're going to throw a curveball at you and ask you to explain the differences between the French Revolution and the Industrial Revolution, you're better off having gotten some sleep." Memory Failure in Old-Age Might Not Be Inevitable While old age is often associated with memory declines, some elderly adults are able to maintain their memory throughout old age. Photo by Sharon Dominick / iStockPhoto While Alzheimer's disease and other age-related memory problems affect many older adults, the loss of memory during old-age might not inevitable. Certain abilities do tend to decline with age, but research have found that individuals in their 70s often perform just as well on many cognitive tests as do those in their 20s. Some types of memory even increase with age. While researchers are still working to understand why exactly some elderly adults manage to maintain an excellent memory while other struggle, a few factors have been implicated so far. First, many experts believe that there is a genetic component to memory retention during old age. Secondly, lifestyle choices are also believed to play an important role. ''I think it's a nature-nurture interaction, in large part,'' Dr. Bruce S. McEwen, a professor at Rockefeller University in New York, explained to The New York Times. ''A genetic vulnerability increases the likelihood that experience will have an effect.'' So what are some steps you can take to stave of the negative effects of aging? According to one decade-long study, having a strong sense of self-efficacy has been associated with having good memory during old age. Self-efficacy refers to the sense of control that people have over their own lives and destiny. This strong sense of self-efficacy has also been linked to lowered stress levels. As mentioned previously, high levels of chronic stress have been connected to deterioration in the memory centers of the brain. While there is no simple "quick fix" for ensuring that your memory stays intact as you age, researchers believe that avoid stress, leading an active lifestyle and remaining mentally engaged are important ways to decrease your risk of memory loss. Top 10 Memory Improvement Tips Improve Your Memory With These Great Tips Before you study for your next exam, you might want to use a few strategies to boost your memory of important information. There are a number of tried and tested techniques for improving memory. These strategies have been established within cognitive psychology literature and offer a number of great ways to improve memory, enhance recall and increase retention of information. 1. Focus your attention on the materials you are studying. Attention is one of the major components of memory. In order for information to move from short-term memory into long-term memory, you need to actively attend to this information. Try to study in a place free of distractions such as television, music and other diversions. 2. Avoid cramming by establishing regular study sessions. According to Bjork (2001), studying materials over a number of session's gives you the time you need to adequately process the information. Research has shown that students who study regularly remember the material far better than those who did all of their studying in one marathon session. 3. Structure and organize the information you are studying. Researchers have found that information is organized in memory in related clusters. You can take advantage of this by structuring and organizing the materials you are studying. Try grouping similar concepts and terms together, or make an outline of your notes and textbook readings to help group related concepts. 4. Utilize mnemonic devices to remember information. Mnemonic devices are a technique often used by students to aid in recall. A mnemonic is simply a way to remember information. For example, you might associate a term you need to remember with a common item that you are very familiar with. The best mnemonics are those that utilize positive imagery, humor or novelty. You might come up with a rhyme, song or joke to help remember a specific segment of information. 5. Elaborate and rehearse the information you are studying. In order to recall information, you need to encode what you are studying into long-term memory. One of the most effective encoding techniques is known as elaborative rehearsal. An example of this technique would be to read the definition of a key term, study the definition of that term and then read a more detailed description of what that term means. After repeating this process a few times, your recall of the information will be far better. 6. Relate new information to things you already know. When you are studying unfamiliar material, take the time to think about how this information relates to things that you already know. By establishing relationships between new ideas and previously existing memories, you can dramatically increase the likelihood of recalling the recently learned information. 7. Visualize concepts to improve memory and recall. Many people benefit greatly from visualizing the information they study. Pay attention to the photographs, charts and other graphics in your textbooks. If you do not have visual cues to help, try creating your own. Draw charts or figures in the margins of your notes or use highlighters or pens in different colors to group related ideas in your written study materials. 8. Teach new concepts to another person. Research suggests that reading materials out loud significantly improves memory of the material. Educators and psychologists have also discovered that having students actually teach new concepts to others enhances understanding and recall. You can use this approach in your own studies by teaching new concepts and information to a friend or study partner. 9. Pay extra attention to difficult information. Have you ever noticed how it's sometimes easier to remember information at the beginning or end of a chapter? Researchers have found that the position of information can play a role in recall, which is known as the serial position effect. While recalling middle information can be difficult, you can overcome this problem by spending extra time rehearsing this information. Another strategy is to try restructuring the information so it will be easier to remember. When you come across an especially difficult concept, devote some extra time to memorizing the information. 10. Vary your study routine. Another great way to increase your recall is to occasionally change your study routine. If you are accustomed to studying in one specific location, try moving to a different spot to study. If you study in the evening, try spending a few minutes each morning reviewing the information you studied the previous night. By adding an element of novelty to your study sessions, you can increase the effectiveness of your efforts and significantly improve your long-term recall. Explanations for Forgetting Reasons Why We Forget What are some of the major reasons why we forget information? One of today's best known memory researchers, Elizabeth Loftus, has identified four major reasons why people forget: retrieval failure, interference, failure to store and motivated forgetting. 1. Retrieval Failure Have you ever felt like a piece of information has just vanished from memory? Or maybe you know that it's there, you just can't seem to find it. One common cause of forgetting is simply an inability to retrieve a memory. One explanation for why retrieval fails is known as decay theory. According to this theory, a memory trace is created every time a new theory is formed. Decay theory suggests that over time, these memory traces begin to fade and disappear. If information is not retrieved and rehearsed, it will eventually be lost. One problem with this theory, however, is that research has demonstrated that even memories which have not been rehearsed or remembered are remarkably stable in long-term memory. 2. Interference Another theory known as interference theory suggests that some memories compete and interfere with other memories. When information is very similar to other information that was previously stored in memory, interference is more likely to occur. There are two basic types of interference: Proactive interference is when an old memory makes it more difficult or impossible to remember a new memory. Retroactive interference occurs when new information interferes with your ability to remember previously learned information. 3. Failure to Store We also forget information because it never actually made it into long-term memory. Encoding failures sometimes prevent information from entering long-term memory. In one well-known experiment, researchers asked participants to identify the correct U.S. penny out of a group of incorrect pennies (Nickerson & Adams). Try doing this experiment yourself by attempting to draw a penny from memory, and then compare your results to an actual penny. How well did you do? Chances are that you were able to remember the shape and color , but you probably forgot other minor details. The reason for this is that only details necessary for distinguishing pennies from other coins were encoded into your long-term memory. 4. Motivated Forgetting Sometimes, we may actively work to forget memories, especially those of traumatic or disturbing events or experiences. The two basic forms of motivated forgetting are: suppression, a conscious form of forgetting, and repression, an unconscious form of forgetting. However, the concept of repressed memories is not universally accepted by all psychologists. One of the problems with repressed memories is that it is difficult, if not impossible, to scientifically study whether or not a memory has been repressed. Also note that mental activities such as rehearsal and remembering are important ways of strengthening a memory, and memories of painful or traumatic life events are far less likely to be remembered, discussed or rehearsed. What are the different causes of forgetting? Answer: i) Physiological causes; Trace decay focuses on the problem of availability caused when memories decay. Hebb said that incoming information creates a pattern of neurons to create a neurological memory trace in the brain which would fade with time. Repeated firing causes a structural change in the synapses. Rehearsal of repeated firing maintains the memory in STM until a structural change is made. Decay theory states that when something new is learned, a neurochemical, physical "memory trace" is formed in the brain and over time this trace tends to disintegrate, unless it is occasionally used. Forgetting that occurs through physiological damage or dilapidation to the brain are referred to as organic causes of forgetting. These theories encompass the loss of information already retained in long term memory or the inability to encode new information again. Examples include Alzheimer's, Amnesia, Dementia, consolidation theory and the gradual slowing down of the central nervous system due to aging. i) Psychological causes; Cue-dependent forgetting or retrieval failure, is the failure to recall a memory due to missing stimuli or cues that were present at the time the memory was encoded. It is one of five cognitive psychology theories of forgetting. It states that a memory is sometimes temporarily forgotten purely because it cannot be retrieved, but the proper cue can bring it to mind. A good metaphor for this is searching for a book in a library without the reference number, title, author or even subject. The information still exists, but without these cues retrieval is unlikely. Furthermore, a good retrieval cue must be consistent with the original encoding of the information. If the sound of the word is emphasized during the encoding process, the cue that should be used should also put emphasis on the phonetic quality of the word. Information is available however, just not readily available without these cues. Interference theory refers to the idea that forgetting occurs because the recall of certain items interferes with the recall of other items. In nature, the interfering items are said to originate from an over stimulating environment. Interference theory exists in two branches, Retroactive and Proactive inhibition each referring in contrast to the other. Retroactive interference is when new information (memories) interferes with older information. On the other hand, proactive interference is when old information interferes with the retrieval of new information Read more: http://wiki.answers.com/Q/What_are_the_different_causes_of_forgetting#ixzz1SQssyTsj Forgetting (retention loss) refers to apparent loss of information already encoded and stored in an individual's long term memory. It is a spontaneous or gradual process in which old memories are unable to be recalled from memory storage. It is subject to delicately balanced optimization that ensures that relevant memories are recalled. Forgetting can be reduced by repetition and/or more elaborate cognitive processing of information. Reviewing information in ways that involve active retrieval seems to slow the rate of forgetting. Forgetting functions (amount remembered as a function of time since an event was first experienced) have been extensively analyzed. The most recent evidence suggests that a power function provides the closest mathematical fit to the forgetting function. History One to study the mechanisms of forgetting was the German psychologist Hermann Ebbinghaus. Using himself as the sole subject in his experiment, he memorized lists of three letter nonsense syllable words—two consonants and one vowel in the middle. He then measured his own capacity to relearn a given list of words after a variety of given time period. He found that forgetting occurs in a systematic manner, beginning rapidly and then leveling off. Although his methods were primitive, his basic premises have held true today and have been reaffirmed by more methodologically sound methods[citation needed]. The Ebbinghaus forgetting curve is the name of his results which he plotted out and made 2 conclusions. The first being that much of what we forget is lost soon after it is originally learned. The second being that the amount of forgetting eventually levels off. [1] [edit] Theories of forgetting The four main theories of forgetting apparent in the study of psychology are as follows; [edit] Cue-dependent forgetting Cue-dependent forgetting (also, context-dependent forgetting) or retrieval failure, is the failure to recall a memory due to missing stimuli or cues that were present at the time the memory was encoded. It is one of five cognitive psychology theories of forgetting. It states that a memory is sometimes temporarily forgotten purely because it cannot be retrieved, but the proper cue can bring it to mind. A good metaphor for this is searching for a book in a library without the reference number, title, author or even subject. The information still exists, but without these cues retrieval is unlikely. Furthermore, a good retrieval cue must be consistent with the original encoding of the information. If the sound of the word is emphasized during the encoding process, the cue that should be used should also put emphasis on the phonetic quality of the word. Information is available however, just not readily available without these cues. [edit] Trace decay Trace decay focuses on the problem of availability caused when memories decay. Hebb said that incoming information causes a pattern of neurons to create a neurological memory trace in the brain which would fade with time. Repeated firing causes a structural change in the synapses. Rehearsal of repeated firing maintains the memory in STM until a structural change is made. [edit] Organic causes Forgetting that occurs through physiological damage or dilapidation to the brain are referred to as organic causes of forgetting. These theories encompass the loss of information already retained in long term memory or the inability to encode new information again. Examples include Alzheimer's, Amnesia, Dementia, consolidation theory and the gradual slowing down of the central nervous system due to aging. [edit] Interference theories Interference theory refers to the idea that when the learning of something new causes forgetting of older material on the basis of competition between the two. In nature, the interfering items are said to originate from an over stimulating environment. Interference theory exists in three branches: Proactive, Retroactive and Output. Retroactive and Proactive inhibition each referring in contrast to the other. Retroactive interference is when new information (memories) interferes with older information. On the other hand, proactive interference is when old information interferes with the retrieval of new information.[2] Output Interference occurs when the initial act of recalling specific information interferes with the retrieval of the original information. [edit] Decay theory Decay theory states that when something new is learned, a neurochemical, physical "memory trace" is formed in the brain and over time this trace tends to disintegrate, unless it is occasionally used.