Explanations of Forgetting
Interference
Interference Theory
One explanation for why we forget is that of interference. This happens when two pieces of information disrupt each other because they are quite similar, with resulting in the forgetting of some of that information.
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There are two types of interference.
Proactive interference occurs when older information interferes with new information. It is pro as it kind of works forward from old to New.
Retroactive interference happens when new information interferes with old information. It is retro as it works backwards.
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McGeoch and McDonald (1931) investigated the effects of similarity and interference with the study using lists of words.
Procedure
Participants were given a list of words to learn until they could remember them perfectly. They were then given a new list of words. There were six groups of participants, all of which had to learn a different new list.
Groups One - synonyms – these are words with the same meanings as the original.
Group Two - antonyms – these are words with the opposite meanings to the originals.
Group Three - words unrelated to the origin list of words
Group Four - consonant syllables
Group Five – 3 digit numbers.
Group Six – A control condition who were given no new list of words.
Findings and Conclusions
It was found that when participants were asked to recall the original list of words the more similar the information was in the second list of words the poorer the recall. For example, in group one where they were given synonyms of the original list of words, recall was worst. However, in group five where participants were given three digit numbers recall was the best out of the five experimental groups.
They concluded that when the information to be remembered is very similar then the effects of interference is greater. Interference leads to poorer recall.
Evaluation
1. One strength of research into interference is that there is evidence from everyday life. Baddeley and Hitch in 1977 conducted a study where they asked rugby players to recall the names of the teams that they had played during that rugby season. The players had all played for the same time interval over that one season, however, the number of intervening games differed because some of the rugby players had missed matches due to injury or not being selected. It was found that players who played the most games, and had more interference, had the poorest recall. Therefore, this study shows that interference can occur in real life situations which increases the validity of the theory.
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2. Further research evidence comes from research into retrograde facilitation. Coenen and van Luijtelaar in 1997 gave participants a list of words and asked them to recall that list. It was assumed that the experiences in between would act as interference. They found that when a list of words was learned under the influence of diazepam (a drug) recall a week later was poor compared to the placebo (control group). But when a list was learned before the drug was taken later recall was better than the placebo. Therefore, the drug seemed to facilitate the recall of material learned beforehand.
Wixted (2004) suggested that the drug prevents new information reaching parts of the brain involved in processing memories, so it cannot interfere retroactively with information already stored. Therefore, this finding shows that forgetting can be due to interference and that if you reduce the interference you reduce the forgetting.
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3. A limitation of interference theory is that interference can sometimes be temporary and can be overcome by using cues. Tulving and Psotka in 1971 gave participants list of words which were organized into categories (but the categories were not made explicit to the participants). It was found that recall was approximately 70% for that first list of words, but became progressively worse as participants learned each additional list. This suggested that there was proactive interference. They then gave the participants category headings from the first list of words (cued recall) and found that recall rose again to 70%. This suggests that recall can be improved by using cues and can help to stop the effects of interference. They concluded that interference causes a temporary loss of accessibility rather than a total loss of memory.
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Retrieval Failure
Retrieval Failure
One reason that people forget information is because they don’t have sufficient cues. When information is placed into memory usually there are cues that are stored there at the same time. Tulving in 1983 referred to the Encoding Specificity Principle. He stated that a cue present at coding also has to be present at retrieval. If the cue is not there at retrieval, then it is more difficult for the person to recall the information.
This theory forms the basis of several memory improvement techniques (mnemonics) such as the Method of Loci.
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There are two types of cues:
Context dependent forgetting – this depends on external cues (e.g. location or weather)
State dependent forgetting – this depends on internal cues (e.g. emotional state)
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Research on context-dependent forgetting
Godden and Baddeley. In 1975 they studied deep-sea divers. They got the divers to learn of list of words in one or four conditions.
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Learn on land – recall on land.
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Learn on land – recall underwater
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Learn underwater – recall on land
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Learn underwater – recall underwater.
Findings and Conclusions
They found that when the cue was the same at coding and retrieval that memory for the list of words was greater than when there was a mismatch. If the cues were different, recall was 40% lower than in the non-matching conditions. For example, learning underwater and recalling on land and learning on land and recalling underwater. They concluded that external cues and the lack of them led to retrieval failure.
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Research on state-dependent forgetting
In a similar study to Godden and Baddeley, Carter and Cassady in 1998 gave an antihistamine drug to participants to look at the effects of internal emotional state. Antihistamines have a mild sedative effect creating an internal physiological state which is different from the normal state of being wide awake. Participants were put into one of four conditions:
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Learn on drug – recall on drug.
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Learn on drug - recall when not drug.
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Learn not on drug – recall when on drug.
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Learn not on drug – recall when not on drug.
Findings and Conclusions
Similar to Godden and Baddeley, Carter and Cassady found that when the conditions were different between the internal state whilst learning and the internal state when recalling information, memory was significantly worse. Therefore, when participants learnt on a drug and recalled not on a drug, their recall was significantly poorer than when they learned on a drug and recalled went on the drug. They concluded that cues at learning must be there when recalling information.
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Evaluation
1. One strength is the finding that there is large body of research that supports the retrieval failure explanation. The studies by Godden and Baddeley and Carter and Cassidy are just two many examples of research that has found contextual cues can help people to remember. Some researchers, Eysenck and Keane (2010) have gone as far as suggesting that retrieval failure is probably the main reason why people forget in long-term memory.
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2. A limitation comes from Baddeley who argues that context effects are not actually that strong in everyday life. His study of the deep-sea divers demonstrated the impact of context, however, the environment of being on land, as opposed to underwater is very different. The difference in environments is probably something which is not going to be a strong in everyday life.
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3. Another strength of research into retrieval cues is that it has real world applications. Even though Baddeley suggests that cues have to be very different in order to effect recall, they can help us if we are trying to remember something that we have forgotten. Cues, whether contextual or state dependent, help us to recall. We use this in everyday life when we retrace our steps when we have forgotten where we have left something.
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4. Another limitation of research into context is that memory might depend on the information that is being tested. Godden and Baddeley replicated the underwater experiment in 1980 but instead of using a free recall task, they used a recognition task instead. When recognition was tested there was no context dependent effect. In fact, performance was the same in all four conditions. They concluded that retrieval failure is therefore a limited explanation for forgetting because it only applies when a person has to recall information rather than recognise it.