Explanations of Forgetting

• Interference


  Forgetting because one memory blocks another, causing one or both memories to be distorted or forgotten
• Proactive Interference (PI)


  Forgetting occurs when older memories, already stored, disrupt the recall of newer memories. The degree of forgetting is greater when memories are similar.
• Retroactive Interference (RI)


  Forgetting occurs when newer memories disrupt the recall of older memories already stored. The degree of forgetting is again greater when memories are similar.
• Memories that are interfering with each other are stored at different times
• Proactive Interference (PI)


  • Older memory interferes with a newer one
• Retroactive Interference (RI)


  • Newer memory interferes with an older one
• To help remember proactive interference, think "P for past"
• To help remember retroactive interference, think "R for recent"
• Evidence From Lab Studies for Proactive Interference


  Research conducted in controlled laboratory conditions
• Keppel and Underwood (1962)

  • Presented participants with meaningless three-letter consonant trigrams and had them count backwards in 3s to prevent rehearsal. Participants typically remembered the trigrams that were presented first, no matter what the interval length was.
• Natural Evidence for Retroactive Interference

  Research in a natural setting
• Baddeley & Hitch (1977)


  • Rugby players asked to recall the names of teams they had played throughout the season, those who had played more games had worse recall than those who played less games.
• Weakness: Research supporting interference theory is often conducted in artificial lab environments and utilises artificial stimuli
• Weakness: Interference can be overcome via the use of cues, suggesting that retrieval failure may be a better explanation of forgetting from LTM
• Proactive interference is when past learning interferes with new learning
• Retroactive interference is when recent learning interferes with old learning
• An experiment was carried out to test the effects of learning similar and dissimilar information on participants' ability to remember.
• Stage 1 of the experiment

  1. 10 participants in Group A (similar condition) were given a list of 20 place names in the UK and given 2 minutes to learn it

  2. 10 different participants in Group B (dissimilar condition) were given the same list of 20 place names in the UK and given 2 minutes to learn it
• Stage 2 of the experiment

  1. Participants in Group A were given a different list of 20 more place names in the UK and given 2 minutes to learn it

  2. Participants in Group B were given a list of 20 boys' names and given 2 minutes to learn it
• Stage 3 of the experiment

  All participants were given 5 minutes to recall as many of the 20 place names in the UK, from the list in Stage 1, as they could
• Measure of central tendency


  A statistical measure that describes the central position in a dataset
• In Stage 3, several participants in Group A recalled words from the Stage 2 list rather than the Stage 1 list
• The encoding specificity principle states that the retrieval cue must match the original encoding
• Retrieval failure is when we can't retrieve information from long-term memory, but it still exists there
• Cues are used to aid recall by providing contextual information about what was encoded
• Interference is when information learned at one time interferes with the learning or retention of other information
• Interference theory


  Information in LTM conflicts with each other, resulting in a distortion or blocking of a memory
• Types of interference


  • Proactive
  • Retroactive
• Proactive interference


  Older memory moves forward to interfere with a newer one
• Retroactive interference


  Newer memory moves backward to interfere with an older one
• The effect of the similarity of information was shown by McGeoch and McDonald (1931)
• When participants were given a list of words to learn followed by a second list, recall of the first list was worse when the second set of information was more similar
• This shows that interference becomes more likely the more similar the information is
• Baddeley and Hitch (1977) found that when rugby players recalled the names of teams they had played in a season, if they had played more games the task was more difficult (rather than if there had been a long time since they had played the matches)
• This shows how interference is a better explanation of forgetting than the mere passage of time
• Encoding specificity principle


  When memories are created, associated cues are stored at the same time. If these cues are not present when trying to recall the information, forgetting will take place
• Context-dependent forgetting


  The external environment differs between learning and recall
• State-dependent forgetting


  The internal state of the person (e.g. alertness) differs between learning and recall