MEMORY: REMEMBERING AND FORGETTING AND THEIR IMPLICATIONS TO EDUCATION
INTRODUCTION:
Memory is generally defined as the processes of encoding, storing and retrieving information. These three processes interact with different memory systems. The memory systems that appear to be most important in the educational area are short-term memory, working memory and long-term memory. Memory is thought to begin with the encoding or converting of information into a form that can be stored by the brain. This encoding process is also referred to as registering information in memory. The memory systems that are involved in the encoding or registration of information in memory are sensory memory and short-term memory.
Sensory Memory
Information which first comes to us through our senses is stored for a very short period of time within the sensory register. Simply put, the sensory register is associated with our five senses – seeing (visual), hearing (auditory), doing (kinesthetic), feeling (tactile) and smelling (olfactory). However, the sensory buffers that have received the most attention in the research literature are the visual and auditory sensory registers.
Generally information remains in our visual memory for a very short time, approximately several hundred milliseconds. This information or "image" is somewhat like an exact replica of what we have just seen, and it fades with the passage of time (Pashler and Carrier, 1996).
Short-term Memory
Most of the information that enters into our sensory registers is not processed further. The information that will be processed further is that which we pay attention to; thus attention is thought to regulate the flow of information from the sensory registers to short-term memory (Gaddes & Edgell, 1994).
Information in short-term memory can be held there indefinitely as long as it is rehearsed, and the typical cause for its loss is that it is displacement by the presence of other, new information that has been attended to (Pashler & Carrier, 1996). Generally, however, short-term memory is considered to be a temporary resting place and information is held there for approximately 30 seconds to two minutes.
There are at least two separate subsystems of short-term memory and some research suggests there may be several more (Pashler & Carrier, 1996). The two subsystems that have been studied the most, and therefore there is clear evidence for are the visual and verbal or auditory short-term memory systems (Baddeley, 1996; Vallar & Papagno, 1995). Visual memory is memory for what we see and verbal or auditory memory is memory of what we hear.
Working Memory
According to some experts in the area of memory (e.g., Baddeley, 1996, 1998; Vallar & Papagno, 1995), just as there are two subsystems of short-term memory, visual and verbal, there are two subsystems of working memory: (1) verbal working and (2) visual working memory. In addition, working memory contains a main controller or central executive that interprets information we have just been presented with and integrates this information with that which we have already stored in long-term memory (Baddeley, 1996). It is helpful to think of working memory as remembering what we are doing while doing it.
Long-term Memory Storage
Just as the sensory and short-term memory systems are associated with the process of encoding or registering information in memory, the long-term memory system is associated with the processes of storage and retrieval of information from memory. Long-term memory storage is considered to be relatively permanent. The loss of information from long-term memory is referred to as forgetting. During the l950's, a good deal of research focused on the issue of whether we forget information simply because time has passed or whether forgetting occurs because what we are learning at the present time interferes with our ability to remember information we learned at an earlier point in time (Baddeley, 1996).
During the normal school day, students are presented with new information, or at least, partially new information, approximately every 45 to 60 minutes. A child may have a 45-minute math lesson during which the process for adding fractions with it is introduced. Then, before this information has had time to consolidate in long-term memory, the student moves on to science where the process of photosynthesis is introduced. This situation produces fertile ground for "forgetting".
Long-term Memory Subsystems.
Just as it was once thought that short-term memory was one system, long-term memory was also considered to be a single system. However, we now know that long-term memory is comprised of a number of interrelated subsystems.
Episodic memory is the memory subsystem that stores information about the "episodes" or events in our lives - remembering what we did during last summer's vacation, who our favorite teacher in school was? Impairments in episodic memory is the basis of classic amnesia (Baddeley, 1996).
Semantic memory is the memory subsystem that stores memory of knowledge and concepts. Formal education can be thought of as filling up our semantic memory "store". Facts such as the rules for capitalization and punctuation are examples of the kinds of information that are stored in the semantic memory system. The task demands for semantic memory in the school setting are unceasing.
Individual differences in semantic and episodic memory provide good rationale for the need for teachers to use multiple, varied learning activities in the classroom, such as projects, group work and field trips. These provide an "episodic" or experiential context within which to place semantic information.
Procedural memory is the memory subsystem that stores the learning of skills, both perceptual-motor and cognitive. Perceptual-motor skills are those such as driving a car, bike-riding and swinging a golf club. Cognitive procedural learning involves skills such as reading and problem solving. While semantic learning can be thought of as storing knowledge of "what", procedural learning can be thought as storing knowledge about "how" (Baddely, 1996).
Squire (1992) also proposed another subsystem of non-declarative memory called priming. Priming refers to the phenomenon that once an object has been perceived or processed, it can be more easily perceived or processed the next time it is encountered (Baddeley, 1996).
In summary, long-term memory consists of two systems: declarative and non-declarative. Declarative memory can be further delineated into the episodic and semantic systems. The non-declarative system includes procedural learning and priming. The characteristics and functions of each specific memory system have important implications for learning and the educational setting.
Long-term Memory Retrieval
Retrieval refers to the phenomenon of accessing information that has been stored in memory. How well information is encoded and stored in memory determines how likely it is to be accessed or retrieved. In addition, information and events that are stored with the new information often referred to as cues, affect the ease with which information can be retrieved (Roediger and Guynn, 1996). Currently, many psychologists believe that retrieval processes are crucial in determining how well information can be remembered or recalled (Roediger and Guynn, 1996).
Retrieval practice for students can be conducted in several ways. One way that is commonly used by teachers is reviewing information prior to testing. But review should not only consist of the teachers' summaries of the information covered; it should also require students to answer review questions asked by teachers, thus "retrieving" the information from long-term memory. Another way in which students may engage in retrieval practice is to make up their own tests, and then answer the questions on their self-made test. A third way to engage students in retrieval practice is to have them ask questions to each other when studying together or to have a parent, family member or tutor ask them questions about the to-be-learned information. According to Baddeley (1996), recognition usually leads to more accurate retrieval of information than recall does. This is because the word or information that has been learned actually serves as a cue, facilitating or enhancing access to its memory trace.
An important phenomenon for educators to understand when using retrieval cues is that the likelihood of recalling items associated with any specific category (i.e., cue) is reduced as the number of items in that category is increased. Additionally, research has shown that in order for retrieval cues to be effective in facilitating the recall of information, they must have been present when the learning took place.
Mnemonic learning might serve as a useful way of getting information into long-term memory. When mnemonics are used during encoding of information, they may provide visual imagery or verbal elaborations that act as cues for recalling information that is low in imagery or in meaningfulness. Visual imagery mnemonics can be ones that learners generate themselves when instructed to form mental pictures to make the material presented to them more memorable, or they can be actual pictures they have been provided with to enable them to form images from what they actually see rather than from what they imagine (Belleza, 1996).
There are several ways in which mnemonic methods can be used in the classroom. First, school children can be taught to generate their own mnemonic devices that they can spontaneously use to help them remember information presented in their classes. Second, mnemonic methods can be induced by instructing children to use a mnemonic strategy to remember a specific set of information prior to its presentation. Third, the teacher can impose mnemonic elaboration upon the student by visually presenting an elaboration (e.g., a picture or drawing) that will both encode the information and organize it in memory.
Metamemory
Metamemory refers to knowledge about how one's own memory processes work. It is important for school children to identify and understand their own memory profiles – their memory strengths and weaknesses. Metamemory can be thought of as a component of meta-cognition or knowing about knowing. Students need to be taught the difference between understanding information and remembering it. They need to know general information about memory such as that encoding activities affect subsequent storage and retrieval of information, that retrieval practice is as important as encoding practice and that elaborative rehearsal is more effective than maintenance rehearsal. They also need to know specific information about their own memory profile such as that their episodic memory system may be better than their semantic memory system or vice versa and that their visual memory may be better than their auditory memory or vice versa.
Techniques used to assess children's memory
Researchers use a variety of tasks to assess children's memory. Some examples are: * Paired associate learning - when one learns to associate one specific word with another. For example when given a word such as "safe" one must learn to say another specific word, such as "green". This is stimulus and response. * Free recall - during this task a subject would be asked to study a list of words and then sometime later they will be asked to recall or write down as many words that they can remember. Earlier items are affected by retroactive interference, or RI, which means the longer the list, the greater the interference, and the less likelihood that they are recalled. On the other hand, items that have been presented lastly suffer little RI, but suffers a great deal from proactive interference, or PI, which means the longer the delay in recall, the more likely that the items will be lost. * Recognition - subjects are asked to remember a list of words or pictures, after which point they are asked to identify the previously presented words or pictures from among a list of alternatives that were not presented in the original list.
Explanations for Forgetting
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: The inability to retrieve a memory is one of the most common causes of forgetting. One possible explanation for retrieval failure 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: Sometimes, losing information has less to do with forgetting and more to do with the fact that it never made it into long-term memory in the first place. Encoding failures sometimes prevent information from entering 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.
THEORIES OF WHY PEOPLE FORGET
Replacement Theory: The replacement theory holds that new information entering the memory replaces old information already stored. Studies that support this theory show that misleading information replaces the original memories of people
Decay Theory: The decay theory holds that some memories will dissipate if not retrieved every once in a while from the long-term memory. According to this theory, the formation of a new memory creates what is known as a memory trace, or a change in brain cells. If this memory is not periodically refreshed, the memory trace gradually fades.
Cue-Dependent Theory: The cue-dependent theory holds that the retrieval of some memories are dependent upon cues that help to locate that information in the brain; if these cues are missing, then you may not be able to remember. Because the mind organizes information based on associations with other things, if you are able to recall an association, that increases your likelihood of recalling the particular information you are seeking
Interference Theory: According to interference theory, information within the memory can interfere with other bits of information during storage or retrieval, thus causing you to forget. This can occur when incoming information is similar to information that is already stored, which can cause confusion when later trying to recall the first-stored information or vice versa. The formerly learned information can interfere with the recollection of the recently learned information.
Techniques for Memory Improvement
There are strategies you can employ to help preserve that information you want to remember and increase the likelihood of its retrieval.
The SQ3R Method: One of the best ways to trap information for future use is to effectively catch it coming in. The way you encode information determines where it is placed in your long-term memory. If information is encoded in a well-organized and efficient manner, the likelihood of its later retrieval increases. The SQ3R method is one of the best encoding strategies.
Mnemonics: Mnemonics are strategies, such as a rhyme or formula, that are used to improve memory and help you retain and retrieve the information by making use of the information already stored in your long-term memory
Another way to boost your memory of facts and information is to teach what you have learned to another person. Study groups can be particularly beneficial to students because each member can take the role of the teacher and relate what he or she has learned to the rest of the group members. As you can see, there are many different techniques that can help boost your ability to store, retain, and recall information. While you should certainly continue to use the strategies that have worked for you in the past, think about incorporating a new method into your normal routine. Researchers have found that adding an element of novelty to your memorization strategy, such as trying a new study technique or varying the location of your study sessions, you can actually boost your long-term recall of the information.
In conclusion, learning, remembering, and forgetting often have been considered separate processes. Yet these distinctions seem to blur in the face of contemporary research and theory

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