Interference

• When does interference occur?

  When two pieces of information disrupt each other, resulting in forgetting of one or both, or in some distortion of memory.
• What type of memory is interference the main explanation for?

  Long-term memory. 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.
• What are the two types of interference?

  • Proactive interference
  • Retroactive interference
• What is proactive interference?

  When an older memory interferes with a newer one. For example, your teacher has learned so many names in the past that they have difficulty remembering the names of their current class.
• What is retroactive interference?

  When a newer memory interferes with an older one. For example, your teacher has learned so many new names this year that they have difficulty remembering the names of their students last year.
• Research on effects of similarity

  In both PI and RI, the interference is worse when the memories are similar, as discovered by John McGeoch and William McDonald (1931).
• What was the procedure of McGeoch and McDonald's study?

  They 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. They then learned a new list.
• What were the lists of the six groups in McGeoch and McDonald's study?

  1. Synonyms
  2. Antonyms
  3. Words unrelated to original ones
  4. Consonant syllables
  5. 3-digit numbers
  6. no new list (control condition)
• What were the conclusions of McGeoch and McDonald's study?

  When the participants were asked to recall the original list of words, the most similar material (synonyms) produced the worst recall. This shows that interference is strongest when the memories are similar.
• What were the findings of McGeoch and McDonald's study?

  
• What is the explanation for the effects of similarity?

  The reason similarity affects recall may be for one of two reasons. It could be due to PI - previously stored information makes new similar information more difficult to store, or it could be due to RI - new information overwrites previous similar memories because of the similarity.