Explanations of Forgetting: Interference

Question 1

Key terms

Answer 1

Interference = Forgetting because one memory blocks another, causing one/both memories to be distorted or forgotten.
Proactive interference (PI) = forgetting occurs when older memories, already stored, disrupt the recall of newer memories. The degree of forgetting is greater when the memories are similar.
Retroactive interference (RI) = Forgetting occurs when newer memories disrupt the recall of older memories already stored. The degree of forgetting is again greater when the memories of similar.

Question 2

Interference theory

At least some forgetting takes place because of interference. This occurs when two pieces of information conflict with each other, resulting in forgetting of one/both, or in some distortion of memory. Interference has been proposed mainly as an explanation for forgetting in LTM. Once information has reached LTM it is more-or-less permanent. Therefore, any forgetting of LTMs is most likely because we can’t get access to them even though they are available. Interference between memories makes it harder for us to locate them, and this is experienced as ‘forgetting’.

Answer 2

Types of interference
It is very likely that the two (or more) memories that are interfering with each other were stored at different times. So psychologists recognise that there are two types of interference:
~ Proactive interference occurs when an older memory interferes with a newer one (pro in this context means working forward, from old to new). 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 happens when a newer memory interferes with an older one (retro meaning working backwards). 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
In both cases, the interference is worse when the memories (or learning) or similar, as discovered by McGeoch & McDonald (1931).
Procedure: McGeoch & McDonald studied retroactive interference by changing the amount of similarity between two sets of material. Participants had to learn a list of 10 words until they could remember them with 100% accuracy. They then learnt a new list. There were 6 groups of participants who had to learn different types of lists: Group 1 - synonyms. Group 2: antonyms. Group 3: words unrelated to the original. Group 4: consonant syllables. Group 5: three-digit numbers. Group 6: no new list - ppts were just retested
Findings: When the participants then recall the original list of words, the performance depending on the nature of the second list. The most similar material (synonyms) produce the worst record. This shows that interferes the strongest with the memories are similar.

Question 3

Evaluation

evidence from lab studies, artificial materials, real-life studies

Answer 3

+ Interference in memory is probably one of the most consistently demonstrated findings in the whole of psychology. Literally thousands of lab experiments have been carried out into this explanation for forgetting. Most of the 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.
- There is a much greater chance that interference will be demonstrated in the lab than in real-life situations, for one good reason. The stimulus materials used in most studies are lists of words. The task facing participants is to learn these lists. Learning lists of actual words is definitely more realistic than learning lists of consonant syllables (such as TZK). But this is still quite some distance from the things we learn and try to remember in everyday life – people‘s faces, their birthdays, the ingredients of our favourite pizza, etc. This is a limitation because the use of artificial tasks makes interference much more likely in the lab. Interference may not be as likely an explanation for forgetting in everyday life as it is in the lab.

+ Some research studies have considered interference effects in more everyday situations. Baddeley & Hitch (1977) wanted to find out if interference was a better explanation for forgetting than the passage of time. So they asked rugby players to try to remember the names of the teams they had played so far in that season, week by week. Most of the players had missed games, for some the last team they played might have been two weeks ago/three weeks ago/more. The results very clearly showed that accurate recall did not depend on how long ago the matches to place. Much more important was the number of times they played in the meantime. So a player’s recall of a team from three weeks ago was better if they had played no matches since then. This study shows that interference explanations can apply to at least some everyday situations.