Interference theory

• 2 types of interference

  • Proactive
  • Retroactive
• Interference

  • 2 pieces of information conflict with each other. This leads to one memory disrupting the ability to recall another.
  • The cause of forgetting memories in the LTM
  • Although memories are still in the LTM, interference can make it difficult for us to access these memories (forgetting)
• Proactive interference

  • Occurs when an older memory interferes with a new one.
  • E,g your teacher has learned so many names in the past, she struggles with the names of her current classes.
• Retroactive interference

  • Happens when a newer memory interferes with an older one.
  • E.g your teacher has learnt so many new names this year she has difficulty remembering the names of the students last year
• Research support for proactive interference

  • Keppel and Underwood
  • Participants presented with trigrams at different intervals
  • To prevent rehearsal the participants had to count backwards in threes before recalling
  • Found that participants typically remembered the trigrams that were presented first, irrespective of interval length.
  • Memory for earlier consonants interferes with memory for new consonants.
• Research support for retroactive interference

  • Underwood and Postman
  • Participants split into groups
  • Both groups had to remember a list of paired words
  • Experimental group also had to learn another list of words where the second paired word was different
  • Control group was not given a second list
  • All participants asked to recall words on first list
  • Recall of control group was more accurate than experimental group.
  • Suggests learning items in the second list interfered with participants ability to recall the list.
• How does similarity effect interference?

  Interference is more likely to occur when the 2 pieces of information are similar- this is due to response competition
• Research support for the effects of similarity

  • McGeoch and McDonald
  • Studied retroactive interference by changing the amount of similarity between 2 sets of materials
  • Participants had to learn a list of words until they could remember them with 100% accuracy
  • They then learnt a new list of words
  • 6 groups with different types of lists: synonyms, antonyms, words unrelated to original ones, nonsense syllables, 3-digit number, no new list.
  • The most similar (synonyms) produced the worst recall. So interference is strongest when memories are similar.
• Support from real life studies

  • Baddeley and Hitch asked rugby players to remember the names of teams they had played week by week. Most players had missed games. Result showed that accurate recall didn’t depend on how long ago matches took place but the number of games they played. A players recall of a team from 3 weeks ago was better if they had played no matches since
  • Players who missed matched, less interference meaning their recall would be better than those who played every match. Furthermore the finding suggest that interference explanations can be applied to everyday situations.
• Interference can be overcome using cues

  • Tulving and Pstoka gave participants lists of words organised into categories, one list at a time. Recall averaged about 70% for the first list but became progressively worse as participants learnt an additional list. Participants were given a cued recall test, they were told the name of categories. Recall rose to 70%
  • Findings suggests that the words have not disappeared from LTm they were just not able to access them, unless they had sufficient cues to help retrieve information.
  • Shows interference causes a temporary loss of accessibility to material
• Artificial materials

  • For example, because most of the research is carried out in a lab, the materials used tend to be lists of words, with a task attached to learn them. McGeoch and McDonald, used word lists in their experiment to investigate the effects of similarity.
  • This is a limitation because this different from what we try to learn everyday e.g peoples faces, their birthdays, details of psychological research. This is an issue because it is difficult to generalise these findings to real life making the theory lack mundane realism
  • Theory lacks external validity
• Reliance of lab experiments- possibility of interference is maximised

  • One example of how this occurs is in the time period between learning lists of words and recalling them. For practical reasons, these time periods are relatively short. Normally studies surrounding interference involve a participant learning a list of words then learning a second list 20 mins later.
  • Issue because we generally do not learn and recall information within such a small amount of time. The longer the time between learning and recall, the less likely there is to be forgetting due to interference.