5. interference

what is interference

interference is forgetting because one memory blocks another, causing one or both memories to be distorted or forgotten

interference types

1. proactive interference (PI) - when an older memory interferes with a newer one

2. retroactive interference (RI) - when a newer memory interferes with an older one

research on effects of similarity

mcgeoch & mcdonald 1931 found intereference is worse when memories (or learning) are similar

procedure

• 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 them with 100% accuracy

• then, they learned a new list

groups of participants

1. synonyms

2. antonyms

3. words unrelated to the original ones

4. consonant syllables

5. three digit numbers

6. no new list (control condition)

findings & conclusions

• when participants were asked to recall the original list of words, the most similar material (synonyms) produced the worst recall

• shows interference is strongest when memories are similar

explanations of effects of similarity

• reason similarity affects recall may be for one or two reasons

  1. could be due to PI - previously stored information makes new similar information more difficult to store

  2. could be due to RI - new information overwrites previous similar memories because of the similarity

evaluation

1. research support (& counterpoint)

2. real world interference (& counterpoint)

3. validity issues

research support

• both studies

validity issues

• interference studies often lack ecological validity

• most supporting research is lab based, allowing high control but lacking real life application - learning word lists in controlled settings does not reflect natural memory processes like revising for exams

• questions how well interference theory explains everyday forgetting

real world interference

• interference happens in every day life, supporting its validity

• baddeley & hitch 1977 found rugby players who played more games forgot more team names than those who played feweer within the same time interval - over one season

• more interevening games caused more interference, leading to poorer recall showing how interference can occur in real life situations

counterpoint

• causation

• while more ecological validity, unclear whether interference was truly due to the number of games played or other factors such as fatigue or motivation

validity issues

• interference is rare in everyday situation

• lab studies create ideal interference conditions (eg two similar memories learned close together) which is uncommon in real life

• means everyday forgetting may be better explained by retrieval failure due to lack of cues, reducing the generalisability of interference theory