Explanations for forgetting: interference

• Interference theory

  • forgetting (mainly in LTM) mainly happens because we can't access memories even though they are available
  • Interference between memories makes it harder for us to locate them, this is experienced as forgetting
  • one memory blocks another causing one or both memories to be distorted or forgotten
• Types of interference

  • proactive interference - old stops new
  • retroactive interference - new stops old
• McGeoch and McDonald - procedure


  • participants had to learn a set of words to 100% accuracy. they were then given a new set of words to remember:

  1. synonyms
  2. antonyms
  3. unrelated
  4. consonant syllables
  5. three digit number
  6. nothing
• McGeoch and McDonald - findings and conclusions

  • most similar material produced the worst recall
  • synonyms blocked access OR new material was confused with old
  • shows that interference is strongest when the memories are similar