Explanations for forgetting

• Interference theory


  Some forgetting takes place because of interference. This occurs when two pieces of information disrupt each other resulting in forgetting of one or both, or in some distortion of memory
• Interference


  Proposed mainly as an explanation for forgetting in long-term memory (LTM). 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. Interference between memories makes it harder for us to locate them, and this is experienced as forgetting
• Types of interference


  • Proactive interference (PI)
  • Retroactive interference (RI)
• Proactive interference (PI)


  Occurs when an older memory interferes with a newer one (pro in this context means working forwards, from old to new)
• Retroactive interference (RI)

  Happens when a newer memory interferes with an older one (retro meaning working backwards)
• In both PI and RI, the interference is worse when the memories (or learning) are similar, as discovered by John McGeoch and William McDonald (1931)
• Procedure of McGeoch and McDonald study

  Participants had to learn a list of 10 words until they could remember them with 100% accuracy. They then learned a new list. There were six groups of participants who had to learn different types of new lists: synonyms, antonyms, unrelated words, consonant syllables, three-digit numbers, and a control group with no new list
• 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
• Explanation of the effects of similarity

  The reason similarity affects recall may be due to PI (new information overwrites previous similar memories) or RI (previously stored information makes new similar information more difficult to store)
• Retrieval failure


  The reason people forget information may be because of insufficient cues. When information is initially placed in memory, associated cues are stored at the same time. If these cues are not available at the time of recall, it may appear as if you have forgotten the information, but this is due to retrieval failure (the information is there but you can't access it)
• Encoding specificity principle


  A cue has to be both (1) present at encoding when we learn the material and (2) present at retrieval when we are recalling it, in order to be helpful. If the cues available at encoding and retrieval are different, or if cues are entirely absent at retrieval, there will be some forgetting
• Some cues are encoded at the time of learning in a meaningful way, and these are used in many mnemonic techniques. Other cues are encoded at the time of learning but not in a meaningful way, leading to context-dependent forgetting and state-dependent forgetting
• Procedure of Godden and Baddeley study on context-dependent forgetting

  Deep-sea divers learned a list of words either underwater or on land, and then were asked to recall the words either underwater or on land. Accurate recall was 40% lower in the non-matching conditions, where the environmental contexts of learning and recall did not match
• Procedure of Carter and Cassaday study on state-dependent forgetting


  Participants had to learn lists of words and passages of prose, and then recall the information. Some participants were given antihistamine drugs, which had a mild sedative effect, creating a different internal physiological state. Performance on the memory test was significantly worse in the conditions where there was a mismatch between internal state at learning and recall