Forgetting

We've forgotten information we've learnt when we can no longer retrieve it. Psychologists say forgetting is because of availability, accessibility and interference problems.

Short-term memory - availability problem

• Information in short-term memory can decay (fade) or be displaced (pushed out). This is because the short-term memory has limited duration and capacity.

• So forgetting information is down to lack of availability.

Long-term memory - accessibility/interference problem

• Forgetting information can be down to:

  • Accessibility - information that was once stored is difficult to retrieve.

  • Interference - memory is inaccessible because of old or new information blocking retrieval.

Interference

Interference happens when some information in our memory is inaccessible because of old or new information blocking retrieval.

Interference

• Sometimes information is stored in our memory, but for some reason it is inaccessible.

• This is known as interference, and there are two types: proactive interference and retroactive interference.

Proactive interference

• Have you ever got a new phone number or moved to a new address, but right after you tell people the old (and wrong) phone number or address? When the new year starts, do you find you accidentally write the previous year?

• These are examples of proactive interference: when old information hinders the recall of newly learned information.

Retroactive interference

• Retroactive interference happens when information learned more recently hinders the recall of older information.

• For example, this week you are studying about Freud’s Psychoanalytic Theory. Next week you study the humanistic perspective of Maslow and Rogers. You then have trouble remembering Freud’s Psychosexual Stages of Development because you can only remember Maslow’s Hierarchy of Needs.

Pros and cons

• Many laboratory experiments support the ideas of proactive and retroactive interference.

• The theory is limited because it does not explain how interference occurs (e.g. the biological or cognitive processes). It only explains why we forget memories.

Study on Retroactive Interference

Underwood and Postman (1960) investigated how retroactive interference affects learning. In other words, does new learning affect your ability to recall previously learnt information?

Procedure

• A laboratory experiment with two groups of participants (control and experimental groups).

• Both groups were given word pairs to learn e.g. dog-bread, chair-fork etc.

• The experimental group was also given a second list to learn where the second word in the pair was changed e.g. dog-cake, chair-window etc. Both groups were then asked to recall the original list.

Results and conclusion

• Result: The recall of the control group was much better than the experimental group.

• Conclusion: The experimental group’s recall had been affected by retroactive interference.

Evaluation

• Strengths

  • Reliable – easy to replicate.

  • Practical applications for education, in particular revision.

• Limitations

  • Lacks ecological validity – not how we use memory in everyday life.

  • The results could be explained by the limited capacity of STM rather than retroactive interference.

  • Interference only really explains forgetting when two pieces of information are really similar.

Study on Proactive Interference

Underwood (1957) investigated how proactive interference affects memory. In other words, do old memories affect your ability to recall new information?

Procedure

• A laboratory experiment.

• Participants were given a list of nonsense syllables to remember and tested 24 hours later.

Results

• Memory was much worse for these nonsense syllables than Underwood expected.

Conclusion

• Underwood concluded that the students’ experience of taking part in memory experiments in the past (even though none involved nonsense syllables) was causing confusion and led to proactive interference.

Evaluation

• Strengths

  • Reliable – easy to replicate

  • Practical application for education, in particular revision.

• Limitations

  • Lacks ecological validity – not how we use memory in everyday life.

  • Interference only really explains forgetting when two pieces of information are really similar.