why do humans forget?

Older memories can interferes with newer, as newer memories can interferes with older.

Forgetting in LTM

As we know, LTM contains a huge pull store of information in which we are not conscious, but from which information can be retrieved into consciousness. Though, people sometimes cannot remember things, which in there LTM. Most psychologist believe that LTM has unlimited capacity, so forgetting cannot be due to displacement.

However, there are some other theories:

• Trace decay
• Interference
• Cue dependence
• Repression
• Schema distortion

Trace decay

As I have mentioned, trace decay theory of forgetting occurs as a result of the automatic decay of the memory trace.

This theory states that memory automatically decay over time. Metabolic processes cause brain cells to break down and decay, as we get older. Particularly, after we get 20-21.

Evidence FOR:

1. En experiment of Ebbinghaus (1885) gave support to this theory, showing that the longer interval between learning and recall, then the greater forgetting, it is increases with the passage of time.
2. Brain cells die increasingly as people draw older – people’s LTM becomes worse. So, it seems logical that old peoples memory is worse then young ones.

Evidence AGAINST:

1. This theory can’t explain why young people forget things, before their brain cells start decaying.
2. Tulving (1968) experiment showed that it is possible to forget information, but then remember it later. Trace decay theory can’t explain it.
3. Older memories should be forgotten before newer memories, but why do we remember our first day at school, but can’t remember the second?

Interference

Our memory may be hampered by information we have already stored, or by new experiences. There are two types of interference:

• Retroactive interference occurs when information you receive later, interferes with your ability to recall something you learned earlier.           E.g. it could happen to someone who knows some Spanish and starts learning Italian. If they try to speak Spanish they may find they are only able to remember words in the new for them language – Italian.
• Proactive interference occurs when something you already know interferes with your ability to take in new information. E.g. if you change your telephone number, you may find it difficult to remember new one. If somebody asks your number, you’ll probably give old one.  

Evidence FOR:

1. Lots of experimental evidence to support interference theory.                   E.g. Baddeley & Hitch (1977) experiment with rugby players.

Evidence AGAINST:

1. Can explain some forgetting, but not all. As a trace decay theory, interference theory can’t explain Tulving experiment.

Cue dependence

This theory was suggested by Tulving (1968). It says that when information goes to LTM, it would always be there. If we can’t remember something, then this is not because memory no longer available, but rather ‘cause we not using right cues to get through the correct part of our memory, where the information is stored.  

There are two types of cues:

• External/ “context” cues. This is about environment or situation in which we store information into our LTM.

Abernethy’s (1940) experiment gave support to these. He taught students for 4 weeks in the same classroom and then gave then a test. But he asked ½ of students to take test in different classroom with different teacher. And he found out that these students did that test worse, then students who took test in the same classroom where they were taught.

•  Internal/ “state” cues, which are related to physiological or psychological states, when we encode information into our LTM.

These applies to our mood, condition etc. E.g. we do better in our exams if we’re in the same mood when we take the test, as we were when we revised.

Evidence FOR:

1. Experimental support.
2. This theory can explain “on tip of the tongue” phenomenon.
3. Physiological evidence from surgical patients.

Evidence AGAINST:

1. It’s still difficult to explain why sometimes we can remember things that happened to us, when we were in different states.

Repression

Sometimes we don’t want to remember things, which make us upset, ashamed, depressed etc. Sigmund Freud suggested that when we find an experience very distressing we push it down into our unconscious so that we can’t access it. Repressions help us to cope with the strong emotional feelings, which the memory creates.  

There some clinical evidence supporting repression theory. Which is the evidence that get from working with people who has psychological problems. Psychoanalytic techniques can be used to access repressed memories. But it may produce quite distressing feelings in the person. And it also may be unreliable. It can cause false memory, like in Loftus experiment.

Also there is an experimental evidence, but it is not very realistic, it rather artificial. (Glucksberg & King’s  “shock” experiment)

There are arguments for and against the repressed memories and we need to find more sensitive techniques for distinguishing between genuine and false repressed memories. It is clear that most forgetting cannot be explained in terms of repression. It is also can’t explain flashbulb memories and posttraumatic stress syndrome.

Schema distortion theory

This theory was suggested by Bartlett. He considered interpretation to play a main part in the way that we remember. Bartlett says that we reconstruct past events in way that make sense to us and fit into our existing schemas of the world. Remembering is not just a question of making an accurate record of the information we receive, but involves fitting the new information into what is already there and create something that make sense.

Bartlett sees world in two ways:

• Process of retrieval involves reconstruction, which is influenced by the frame-works that people already have in their heads. This helps us to organize and make sense of incoming information. Schemas will influence the way we take in information.
• Schemas also affect the way we recall information, because they may distort recall in way that is consistent with the schema. His “The War Of The Ghosts” experiment gave some suppotr for this.

Evidence FOR:

1. Experimental evidence to support Bartlett theory.
2. This theory is more valid to everyday life, then any other theory.

Evidence AGAINST:

1. Bartlett “The War Of The Ghosts” experiment – that story was strange and difficult to understand. It was a bit artificial.
2. Also can’t explain flashbulb memories.

                                   

                                               Conclusion

So, why do humans forget? There are many reasons why, although it is rather difficult to test them because we may not in fact forget, we may be unable to retrieve the memory from our storage. These theories of forgetting are therefore also possible explanation for why we seem to be unable to retrieve a memory, or why that memory is distorted.

This can’t give a correct answers, it just can make us understand more clearly “how all that work”.

References:

• Psychology notes
• BUTLER, G. 1998 “Psychology. A very short introduction” Oxford,       Oxford University Press.
• RICE, D. 2000 “Psychology in Focus. AS Level” Haddington, CPL.
• WOODS, B. 2001 “Psychology First” London, Hodder&Stoughton.