– Forgetting is the loss of the ability to recall or recognise something they have previously learned
INTERFERENCE THEORY
– Interference is an explanation of forgetting as one memory disrupts the ability to recall another.
– As the two pieces of information conflict with each other, it results in forgetting or distortion in one or both of the memories
– This is more likely to happen if the memories have some similarity
– It is likely that the conflicting memories were stored at different times and this lead psychologists to recognise that there are two types of interference: proactive and retroactive
PROACTIVE INTERFERENCE
– Occurs when an older memory interferes with a newer one.
– For example, your teacher has learned so many names in the past that she has difficulty remembering the names of her current class,
RETROACTIVE INTERFERENCE
– Occurs when a newer memory interferes with an older one.
– For example, your teacher has learned so many new names this year that she has difficulty remembering the names of the students last year
EFFECTS OF SIMILARITY
– As discovered by McGeoch and McDonald (1931), in both types the interference is worse when the memories are similar
PROCEDURE
– They studied retroactive interference by changing the amount of similarity between two sets of materials.
– Participants had to learn a list of 10 words until they could remember then with 100% accuracy.
– They then learned a new list.
– There were six groups of participants who had to learn different types of lists:
– Group 1 – Synonyms
– Group 2 – Antonyms
– Group 3 – Words Unrelated to the Original List
– Group 4 – Nonsense Syllables
– Group 5 – Three-digit Numbers
– Group 6 – A Control Group.
FINDINGS
– They found that when the participants 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.
EVALUATION OF INTERFERENCE
STRENGTHS
Evidence from Lab studies
– Thousands of lab studies have been carried out into interference theory.
– Most of these studies show that both types of interference are very likely to be common ways we forget information from LTM.
– This is a strength because lab experiments control the effects of irrelevant influences and thus give us confidence that interference is a valid explanation for at least some forgetting.
Real life studies
– In 1977 Baddeley and Hitch wanted to find out if interference was a better explanation for forgetting than the passage of time.
– They asked rugby players to try to remember the names of the teams they had played so far in that season, week by week.
– The results clearly showed that accurate recall did not depend on how long ago the matches took place.
– Much more important was the number of games they played in the meantime.
– This study shows that interference explanations can apply to at least some everyday situations.
– Therefore, increasing validity.
LIMITATIONS
Artificial Materials
– One issue with the evidence offered in support of both pro and retroactive interference concerns the methodology of the studies.
– Most of this research used rather artificial lists of words and/or nonsense syllables.
– Thus, the findings may not relate to everyday uses of memory, which tend to not involve word lists.
– In addition, participants may lack motivation to remember that links in such studies, and this may allow interference effects to appear stronger than they really are.
– This means that research is low in ecological validity and interference may not be a likely explanation for forgetting in everyday life like it is in the lab.
Incomplete Explanation
– Another criticism of research into interference is that interference does not occur that often.
– Rather special conditions are required for interference to lead to forgetting as the two memories need to be quite similar.
– For this reason interference is considered a relatively unimportant explanation for everyday forgetting.
– Anderson concluded that interference does play a role in forgetting but how much it contributes remains unclear
– This means that other theories are needed to provide a complete explanation of forgetting.