Interference Theory

What is interference?

Two pieces of informations disrupt each other, resulting in the distortion/forgetting of one or both of the memories

Why would a LTM be forgotten?

If it cannot be accessed

What is proactive interference?

An older memory interferes with a newer one

What is retroactive interference?

When a newer memory interferes with an older one

What did McGeoch and McDonald (1931) research?

How retroactive interference affects memory by changing the amount of similarity between materials

What was McGeoch & McDonald (1931)’s procedure?

• Participants learned 5 different lists of words, with a different degree of similarity, until they knew them 100%

• They then learned a new list → after, they had to recall the original list of words

What were McGeoch and McDonald (1931)’s findings?

• When participants were asked to recall the original list of words synonyms produced the worst recall

• Control group with no new list recalled the most

• Shows interference is strongest when memories are most similar

What are the strengths of interference theory?

• Real-world evidence

• Support from drug studies

What are the limitations of interference theory?

• Other explanations

• Interference may only cause a temporary loss

What real-world evidence is there to support interference theory?

• Baddeley and Hitch (1977) asked rugby players to recall the names of the teams they played against during rugby season

• Some players played more games than others due to injury

• Players who played the most games had the poorest recall

• Increases validity as it shows interference occurs in real life

What research support is there for interference theory?

• Coenan & Luitelaar (1997) gave participants a list of words which they would later recall

• When recalling under the influence of drugs, recall one week later was poorer than the placebo group

• When the list was recalled before the drug was taken, later recall was better than the placebo

• The drug improved recall of material learned beforehand

• Wixted (2004) suggests the drug prevents new information being processed, so it cannot retroactively interfere with old information

What other explanations are there for forgetting?

The conditions required for interference to occur are rare - everyday forgetting may be better explained by retrieval failure

Why is interference theory only a temporary loss?

• Tulving and Psotka (1971) gave participants lists of words, one at a time

• Recall for the first list was 70%, but became progressively worse with each additional list → proactive interference

• At the end, participants were given a cued recall test, which rose recall back to 70%

• Suggests interference only causes a temporary loss of accessibility to LTM → not included in interference theory