explanations for forgetting: interference

• ao1: Interference theory

  • Interference: when two pieces of information disrupt each other.
  • Forgetting occurs in LTM because we can't get access to memories even though they are available.
  • Proactive interference (PI) - old interferes with new.
  • Pl occurs when an older memory disrupts a newer one.
  • For example, a teacher learns many names in the past and can't remember names of her current class.
  • Retroactive interference (RI) - new interferes with old.
  • RI happens when a newer memory disrupts an older one.
  • For example, a teacher learns many new names this year and can't remember the names of her previous students.
  • Interference is worse when memories are similar.
  • This may be because:
  • In Pl previously stored information makes new information more difficult to store.
  • In RI new information overwrites previous memories which are similar.
• ao1: McGeoch and McDonald 1931 Effects of similarity- PROCEDURE

  • Participants were asked to learn a list of words to 100% accuracy (i.e. could recall them perfectly).
  • Then they were given a new list to learn The new material varied in the degree to which it was similar to the old:
  • Group 1 synonyms - words had same meanings as the originals,
  • Group 2: antonyms - words had opposite meanings to the originals.
  • Group 3: unrelated - words unrelated to the original ones.
  • Group 4: consonant syllables
  • Group 5. three-digit numbers.
  • Group 6: no new list - participants just rested (control condition)
• ao1: McGeoch and McDonald 1931 effects of similarit- PROCEDURE

  • Participants were asked to learn a list of words to 100% accuracy (i.e. could recall them perfectly).
  • Then they were given a new list to learn The new material varied in the degree to which it was similar to the old:
  • Group 1 synonyms - words had same meanings as the originals,
  • Group 2: antonyms - words had opposite meanings to the originals
  • Group 3: unrelated - words unrelated to the original ones.
  • Group 4: consonant syllables
  • Group 5. three-digit numbers.
  • Group 6: no new list - participants just rested (control condition)
• ao1: McGeoch and McDonald 1931 Effects of similarity FINDINGS NAD CONCLUSIONS

  • 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 The findings are shown in the graph on the left.

  
• ao3: One strength is some support for interference in real-world situations.

  • Baddeley and Hitch (1977) asked rugby players to recall the names of teams they had played against during a rugby season.
  • Players did not play the same number of games (injuries). Those who played most (more interference) had poorest recall
  • This shows that interference operates in some everyday situations, increasing the validity of the theory
• ao3: COUNTERPOINT TO BADDELEY AND HITCH STRENGTH

  • Interference in everyday situations is unusual because the necessary conditions are relatively rare e g similarity of memories/learning does not occur often.
  • Therefore most everyday forgetting may be better explained by other theories (e g. retrieval failure due to lack of cues).
• ao3: One limitation is that interference effects may be overcome using cues.

  • Tulving and Psotka (1971) gave participants lists of words organised into categories (not told what they were).
  • Recall of first list was 70% but fell with each new list (interference). When given a cued recall test (names of categories) recall rose again to 70%.
  • This shows that interference causes just a temporary loss of access to material still in LTM-not predicted by theory.
• ao3: Another strength is support from drug studies.

  • Material learned just before taking diazepam recalled better than a placebo group one week later - this is retrograde facilitation (Coenen and van Luijtelaar 1997).
  • The drug stopped new information reaching brain areas that process memories, so it could not retroactively interfere with stored information (Wixted).
  • This shows that the forgetting is due to interference - reducing the interference reduced the forgetting