A few key terms that will probably confuse: LTM = long term memory,
STM = short term memory.

Memory can be described as the ability to retain past experiences and the ability to recall these experiences. In many circumstances memory is important in the working and personal lives of every living person. Remembering the skills needed to play football, remembering a loved one's birthday or other significant social event, arguably even more important, remembering which side of the road to drive on and remembering the importance of the laws of gravity.

This entry is designed as a short explanation of the psychology of Memory and Forgetting.

Memory

There are three main types of memory; Iconic and Echoic Memory, Short Term Memory and Long Term Memory, they can be categorised by their method of Encoding, Storing and Retrieving information.

Iconic and Echoic Memory

Our Iconic and Echoic Memory acts as a buffer for input from the senses (Iconic - Vision, and Echoic- Hearing) before the information goes on to Short Term Memory.

The encoding in Iconic and Echoic Memory is precategorical; the information is stored for a very short time and the information is retrieved by means of serial -going through every piece of information in order- transfer to short term memory.

Iconic and Echoic Memory lasts for about 1 second before starting again. We are usually unaware of such memory because the information is constantly lost and replenished.

The most important point to remember about Iconic and Echoic memory is that, it acts as a store for holding information while it is being put into categories before moving on to STM and LTM. Iconic and Echoic memory decays very quickly if it does not enter STM.

Short Term Memory

STM is our "working memory" during the processing and learning of information. It encodes information categorically and is largely verbally based.

STM stores information for around 20 seconds and this information can be maintained by rehearsal. It also has a limited capacity of (7 + or - 2) these can be grouped e.g. 7 + or-2 letters, Words, 7+/- 2 numbers...

Information is retrieved in STM by means of a Rapid Serial Readout (It goes through every piece of information in STM and then comes back again with an answer).

In STM information is not always being recalled from STM alone, some previously learned information may be coming from LTM.

The Suffix Effect is very important in STM: This is when a peice of information which is learned at the end of learning replaces a peice of information learned at the start of learning. e.g. when learning a simple list of numbers (1 2 3 5 6 7 9 4) the number nine or four might replace the number one.

Long Term Memory

LTM differs from STM in a two key ways; first of all it is permanent and durable. Secondly LTM does not decay over time (except of course with conditions such as Alzheimer’s). Information in STM is replaced by new information coming in or goes into LTM, nothing is permanently in STM.

Information is encoded in LTM based on Meaning (for example the meaning of dog; animal, canine, perhaps pet, pet names). Information is stored in LTM based on the time the information has spent in STM (the longer information stays in STM, the more likely it is to get into LTM), and is stored in the context in which it occurred (say you learned information in a class, taught by a teacher, this information would be grouped with the information learned) with no time or capacity limit. Information is retrieved from LTM by some sort of search, finding a path to the memory via associations (an example of an association is, to use dog again, dog, animal, pet, childhood pet or current pet, pet name e.g Bengi.

However, there are some problems within LTM; Not all LTM memories stored with context, Information is not always stored relating to time in STM, some information gets lost (for example there is some evidence that people can, over time, or other reasons, forget the associations but retain the actual information).

Information in Long Term Memory can be split into two sections: Episodic; autobiographical, stored relating to time and place and Semantic; general conceptual knowledge (meanings of words) not stored relating to time and place.

Forgetting

A common belief is that our memory decays over time. This is called decay theory: the breakdown of information unless it is preserved by practice and reiteration. It is the reason for loss of information in Iconic and Echoic memory but only partially in STM and not at all in LTM.

One theory of forgetting is that the information is simply displaced by new material coming into short term memory due to its limited capacity and because of this it didn’t get into long term memory. Waugh and Norman (1965) explored this through a “serial probe task”, the participants were shown a sequence of 16 numbers at either four or one per second and were then shown one of the digits (the probe) and asked to say which number followed. The idea was that if the number was at the start of the task then it would have been displaced by a later number but if it was at the end then it should be remembered. The results supported this theory. However in the four per second task the numbers were remembered more easily, this also ties in with decay theory.

Retrieval failure theory suggests that information is not lost but that the right cues are not being used. An example of this is Childhood amnesia, this is when an adult cannot remember events before their fourth or fifth birthday, this can be explained by understanding that things around them and the way they see things would be very different as a young child, compared to when they became an adult. Thus they have no cue to remember the information. The tip of the tongue study was done by Brown and Mcneill (1966). In this they read out dictionary descriptions of unfamiliar words to participants and most either knew the word or knew that they did not know the word. However there were some who did not know whether they knew the word or not and some of these people could give the word’s first letter and even how many syllables it had but could not remember the word. It can be seen from this that the words were in their memories but they had not used the correct cue to access it. This cannot be explained by other theories such as decay theory.

Interference theory. In this theory forgetting occurs because of what has happened before or after learning. Retroactive interference is when information learned after learning interferes with recall (e.g. Jim learned about the D.Day landings, he then learned about the first world war, and the information about the first world war prevented him from fully recalling the information about the D.Day landings. Proactive interference is when information learned before learning interferes with recall (e.g. John learned 10 numbers he then learned 10 completely different numbers, the first 10 numbers prevented him from fully recalling the second 10 when asked).

When the information being recalled is similar in each trial, interference can be prominent, but when the topic of the experiment changes (for instance if the questions in the first three trials were on recalling dog breeds and then changed to recalling numbers in the fourth trial) there would be- like the first trial- a high rate of recall.

To sum up, the main reasons for forgetting are: in STM; some decay and information being displaced by new information coming in and not getting into LTM. In both LTM and STM; failure of retrieval due to incorrect retrieval cues and Information learned either before or after learning, Interfering.

This of course does not apply to conditions such as Alzheimer’s and Amnesia, which are biological reasons for forgetting but it does explain general forgetting.

One very important thing to remember is that information never leaves our brains after getting into LTM (except of course for biological reasons). However retrieval cues can get harder to find the further we are from them, for example; an old woman in a nursing home is less likely to remember her childhood than an old woman in her childhood home.

Remembering, Learning and Improving our Memory

The best way to Learn/ Remember information is to:

• Keep It Organised
• Associate it with something (preferably funny, elaborate or easy to remember)

One way of doing this is by using Mnemonics - An old history one: FREAC POV France Russia Empire America Cost Public-Opinion Versailles- and then learn each paragraph under its heading.

Rehearsal (just going over it, over and over again) is not a good way of learning.

Another way of ensuring remembering (recall) is by reinstating the conditions of learning e.g. Going to where you last remember having your towel to remember what you did with it or taking an exam in the room in which you studied.

Another example is if you were drunk or under water when you said or did something, you are more likely to remember what it was if you get drunk or go underwater at the same place and time.

Hypnosis has also proved to be a useful way of remembering information lost in LTM, however the person doing the hypnotising must know the correct retrieval cues and hypnosis does not work on everyone.