Explanations for Forgetting- Interference Theory

Forgetting is on the other side of the coin to remembering.

Psychologists have tried to understand and explain it by carrying out research studies formulating theories about why we forget.

Interference theory is an explanation of forgetting in terms of one memory disrupting the ability to recall another.

This is most likely to occur when the two memories have some similarity.

It has been proposed mainly as an explanation of forgetting in the LTM.

It is very likely that the two (or more) memories that are interfering with each other were stored at different times. 

Therefore, psychologists recognise that there are two types of interference:

1) Proactive interference

2) Retroactive interference

In both cases of retroactive and proactive interference, the interference is worse when the memories are similar.

This type of interference occurs when and older memory interfers with a newer one.

For example, you have learnt your old phone number so well that you cannot remember your new one.

This type of interfence occurs when a newer memory interfers with an older one.

For example, you learn Spanish now and have diffuculty remembering the French you learnt last year.

McGeogh and McDonald (1931) showed this in a study of retroactive interference by changing the amount of similarity between two sets of materials.

Participants had to learn a list of ten words until they could recall them with 100% accuaracy.

Then they learned a new list. There were six different groups whom all learned different types of lists:

1. Synonyms- words with the same meanings as the originals
2. Antonyms- words with the opposite meanings to the originals
3. Words unrelated to the original ones
4. Nonsense syllables
5. Three- digit numbers
6. No new list- these participants just rested

When participants then recalled the original list of words their performance depended on the nature of the second list.
The most similar material (synonyms) produced the worst recall. This shows that interference is strongest when the memories are similar.

STRENGTH

Evidence from lab studies consistently demonstrates interference in memory.

Many lab experiments have been carried out into interference.

Most of these studies show that both types of interference are very likely to be the cause of forgetting from the LTM.

Lab experiments control the effects of extraneous variables and so give us confidence that interference is a valid explanation.

STRENGTH

Real-life studies have supported the inferference explanation.

Baddeley and Hitch (1977) asked rugby players to recall the names of teams they had played so far in that season, week by week.

Accurate recall did not depend on how long ago the match took place.

More important was the number of games played in the meantime.

This study shows that interference explanations can apply to at least some everyday situations.

LIMITATION

The research used artifical materials as the stimulus material used is quite often word lists.

This is more realistic than consonant syllables, but is still quite different from things we remember in everyday life.

For example, in everyday lifewe remember people's faces, their birthday, and the ingredients of our favourite food.

The use of artifical materials makes interfence much more likely in the lab and it may not be a likely cause of 'everyday' forgetting.

LIMITATION

Time periods between learning lists of words and recalling them are quite short in lab studies.

A participant might learn two lists of words in 20 minutes.

Research reduces the whole experience of learning into a short time period, which does not reflect how we learn and remember most information in real life.

Therefore, the conclusions drawn from research into forgetting in LTM may not generalise outside the lab and the role of interference may be exaggerated.