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Why do we forget information? Find out in this fascinating article exploring the purpose of forgetting.


Do we really forget?

Many people think that the human mind is too complex to explain, and memory is no exception. Even though vast amounts of research have been carried out into how we remember (and forget!) things, nobody knows for sure the model on which human memory is based.


There are, nonetheless, two main reasons for which psychologists think we 'forget' information:

  • You store information in your memory but are unable to remember it when you need to, but perhaps can at a later date. In this case, information is inaccessible
  • The human memory simply forgets information, permanently, and the physical traces of the memory disappear. In which case, information is unavailable

How We Forget

It's though that how we forget differs depending on whether a memory is stored in our long term or short term memory (see multi-store explanation).

In Short-Term Memory

There are three ways in which you can forget information in the STM:

  1. Decay
    This occurs when you do not 'rehearse' information, ie you don't contemplate it. The physical trace of such memory is thought to fade over time.
  2. Displacement
    Displacement is quite literally a form of forgetting when new memories replace old ones. Everyone knows the potentially vast capacity of memory, particularly long-term memory, but research by Norman has shown that numbers can replace old ones being memorised (using the serial probe technique).
  3. Interference
    It's sometimes difficult to remember information if you've been trying to memorise stuff that's similar, eg words which sound similar (in 1966, psychologist Baddeley found that participants of his study found it easier to remember words which were more distinguished). Interference can either be proactive (this is when old memories interfere with new ones) or retroactive, when new information distorts old memories.

In Long-Term Memory

Long term is supposed to be limitless in its capacity and length in terms of time. Still though, we can forget information through decay (as in short-term forgetting) and interference from other memories.


Although we evidently can 'forget' information, it's unknown whether information does actually disappear from memory. In hypnosis, memories which we never knew still existed can be recalled from early childhood using regression, calling into question - can we really forget?

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