Explanations for Forgetting: Interference

What is the Interference Theory?

• Once information reaches LTM it is more or less permanent.

• ‘Forgetting’ in LTM occurs because we can’t access the memories.

• Interference theory states that foretting occurs because memories interfere with one another and end up disrupting each other leads to forgetting (Baddeley, 1999)

What are the types of Interference?

• Retroactive interference

• Proactive interference

What is Retroactive Interference?

• When recent information hinders the recall of older information

• Eg: Calling your ex-girlfriend by new girlfriend’s name.

What is Proactive Interference?

• When past information hinders the recall of new information

• Eg: Remembering old phone number instead of the new one

Describe McGeoch and McDonald’s investigation:

• They studied retroactive by varying the amount of similarity between sets of word lists presented to participants.

• In their, experiment, all participants had to learn a new list of 10 words until they could remember them with 100% accuracy.

• They were then split into 6 groups and each group was required to learn a new list.

• After all participants learnt list 1, they were split into six groups where each group had to a learn one of the 6 word lists.

What were the 6 word lists used?

• Synonyms

• Antonyms

• Words unrelated to list 1

• Nonsense syllables (bhljw)

• 3 digit numbers

• No new list

What were the findings of McDonald and McGeoch’s investigation?

• Synonyms produced the worst recall showing that interference is strongest when memories are similar.

• Those who had learned synonyms in the second list were significantly impaired down to 12%

• The order of best to worst recall was: synonyms, Antonyms, Unrelated adjectives, Nonsense syllables, Numbers, No new list.

What is the impact of evidence from Lab studies on McGeoch and McDonald’s investigation?

• Thousands of lab experiments have been done for explanations of forgetting.

• Most of the studies show that both types of interference are very likely to be common ways we forget information from LTM.

• It supports their investigation as lab studies control the effect of extraneous variables and increase validity.

What is the impact of Artificial Materials on McGeoch and Mcdonald’s investigation?

• The stimulus materials used in most studies are word lists.

• Although learning lists of words is definitely has more mundane realism that learning consonant trigrams (such as TZK), this still doesn’t accurately represent the thing we learn and try to remember in everyday life ie: faces, birthdays, grocery lists.

• It is a limitation of the investigation as it makes interference much more likely in the lab.

• Interference may not be as likely an explanation for forgetting things in everyday life as it is in the lab.

How do Real-life studies impact McGeoch and McDonald’s research?

• Baddeley and Hitch (1977) wanted to find out if interference was a better explanation for forgetting than time elapsing.

• They asked rugby players to remember the names of the teams they had played in that seasons week by week.

• The results clearly showed that accurate recall did not depend on how long ago that matches took place but what was more important was the number of games they played in the meantime.

• This supports the investigation as it shows that interference can apply to at least some everyday situations.

How does time between learning impact McGeoch and McDonald’s research?

• For practical reasons, in interference studies the ti,e periods are relatively short and sometimes very short.

• This means that a participant may have to learn one list of words and then learn a second one 20 minutes later later, and then recall one of them a few minutes after that. The whole process could be done in 1 hour.

• This is a limitation of their research because it doesn’t necessarily reflect how things are learnt in the real world and questions the validity of experiments investigating interference.

How does interference effects being able to be overcome using cues effect McGeoch and McDonald’s research?

• Tulving and Psotka (1971) gave participants lists of 24 words, each list organised into 6 categories.

• The categories were not explicit but it was presumed that they would be obvious to participants.

• Recall was about 70% for the first word but this fell as participants were given each additional list to learn presumably due to interference.

• However at the end they were given a cued recall test, they were told the names of the categories as a clue, recall again rose to about 70%.

• This is a limitation of the research because when a cue was present, participants were able to recall more words.

• This shows that participants did have the information stored in LTM but because of the similarity between words, interference was likely to take place.