Lecture 9...

Everyday Memory

  1. Forgetting
  2. Flashbulb Memories/False Memories
  3. Eyewitness Testimony
  4. Improving Memory

Forgetting

 Forgetting happens when information we had previously stored in memory becomes somehow “lost”, with the result that we cannot retrieve it.

Forgetting curve

Hermann Ebbinghhaus- the first to systematically investigate forgetting.

  • Developed series of pronounceable syllables which were essentially C-V-C (consonant – vowel –consonant) sequences, e.g. wux, zol, bup, which could be pronounced, but had no meaning.
  • Taught himself lists of nonsense syllables
  • Then RELEARNED this after variable time intervals (ranging from 21 minutes to 31 days)
  • Forgetting curve- examining how much of each list he had remembered at each time interval Ebbinghaus could study how much information was forgotten as a function of time
  • Results- curve shows that forgetting is rapid at first, but gradually slows down; this resembles a logarithmic relationship between time and forgetting.

Theories of forgetting

What causes forgetting?

  • Consolidation Theory
  • Decay
  • Interference
  • Cue and Context

Consolidation Theory

  • Memory traces or representations consolidate (strengthen) over time.
  • Older memory traces are less sensitive to forgetting than recent memory traces
  • We are more likely to forget very recent information than we are likely to forget information that we acquired a long time ago.
  • In this sense consolidation of memory traces prevents their forgetting.
  • Jost’s Law- recently stored information will be forgotten faster than information stored earlier. --- If older memories have more time to consolidate they may be less vulnerable to decay and interference than newly formed memories.

        

Decay and Interference Theory

  • According to the Decay Theory, forgetting occurs inevitably with the passing of time.
  •  Thus, it is the amount of time that determines forgetting; the longer time passes between a study and recall stage, the greater forgetting.

Early research suggests that interference plays a larger role in forgetting than decay over time.

  • Jenkins and Dallenbach (1924)- discovered that memory for words was better after a period of sleeping than after a period of waking.
  •  Presumably the newly learned information was interfered with by cognitive activity during the waking period, and this interference did not occur during sleep.

Later Research...

  • Underwood (1957)- observed 2 types of interference
  • Proactive Interference- influence of previous items on recall for later items
  • Retroactive Interference - the influence of recent items on recall of earlier items
  • Forgetting is mainly caused by retroactive interference (RI): we take in new information all of the time and it is likely that at least some of that information will displace or replace existing knowledge, hence causing forgetting of that previous knowledge.
  • However, forgetting can also be caused by proactive interference (PI)...
  • Underwood (1957) - investigated why participants in his experiment were so poor at remembering lists of nonsense syllables just 1 day after learning them.
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  • Participants who had previously learned many lists of nonsense syllables (during previous experiments) were more likely to forget current lists.
  • This finding illustrates proactive interference: memory of older learned syllables interfered with the recently learned items.

Technique to investigate proactive and retroactive interference: PAIRED ASSOCIATION LEARNING TASK

  • Participants learn lists of word pairs.
  •  Memory is subsequently tested by presenting the first word of each pair (the cue) and the participant has to give the second word (the target).
  •  By combining the same cue word with different target words on different learning stages (see ...

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