Forgetting

Forgetting is when learnt information can’t be retrieved:

1. Experiments on memory assume that if you can’t retrieve a memory. it’s forgotten.

2. Forgetting information from STM is thought to be down to an availability problem- the information is no longer available because of the limited capacity or the limited duration of STM. The information may have been pushed out (displaced) or simply have faded away (decayed).

3. In long-term memory forgetting can be caused by decay (an availability problem’, but it can also be because:

   • The information was stored, but is hard to retrieve- as an accessibility problem, e.g. you read something once, a long time ago, and now need a lot of help to recall it.

   • The information is confusing- there is an interference problem, e.g. two pieces of learnt information are too similar, and you can’t tell them apart easily

Interference is one explanation for forgetting:

• One theory about forgetting is that your ability to remember a particular thing you’ve learnt can be affected by having learnt something similar before or since. This is known as interference- there are two types:

  • Retroactive Interference: It is where new information interferes with the ability to recall older information.

    • Underwood and Postman (1960) carried out a study which supported retroactive interference. In a lab experiment, participants were split into two groups. Both groups were given a list of paired words to learn, e.g. cat-tree. The experimental group was then given a second list of words to learn, where the first words in each pair were the same as in the first list, e.g. cat-dirt. The control group wasn’t given a second-word list both groups were then tested on their recall of the first-word list, by being given the first word from each pair. Recall was better in the control group, suggesting that retroactive interference of the second-word list had affected recall for the environmental group.

  • Proactive interference: It is where older information interferes with the ability to recall new information

    • Underwood (1957) studied proactive interference by looking at the results of studies on forgetting over a 24-hour period. He found that if people had previously learnt 15 or more word lists during the same experiment, a day later their recall of the last word list was around 20%. If they hadn’t learnt any earlier lists, recall a day later was around 80%. Underwood concluded that proactive interference from the earlier lists had affected the participants’ ability to remember later ones.

The interference theory has strengths and weaknesses:

1. Proactive and retroactive interference are supported by loads of studies, many of which were highly controlled laboratory experiments.

2. As well as in laboratory experiments, there is evidence for interference existing in real-world settings too. For example, you might struggle to remember your French vocabulary if you later start learning German.

3. However, interference effects seem much greater in artificial laboratory settings than they do in real life, so it may not be as strong a theory as once thought.

4. The theory gives us an explanation for why we forget, but it doesn’t go into the cognitive or biological processes involved- it doesn’t fully explain why or how interference happens.

Underwood and Postman (1960): Interference study

Aim:

• To find out if new learning interferes with previous learning.

Method:

• Participants were divided into two groups. Group A were asked to learn a list of word pairs i.e. cat-tree, they were then asked to learn a second list of word pairs where the second paired word was different i.e. cat - glass. Group B were asked to learn the first list of word pairs only. Both groups were asked to recall the first list of word pairs.

Results:

• Group B’s recall of the first list was more accurate than the recall of Group A's.

Conclusion:

• This suggests that learning items in the second list interfered with participants' ability to recall the list. This is an example of retroactive interference.

Evidence for proactive interference:

• Demonstrated by Keppel & Underwood (1962)

• They asked participants to recall consonant trigrams (e.g THG) after varying intervals (3,6,9, secs), during which they counted backwards in 3s (prevents rehearsal).

• They found that, while forgetting was found to increase with the interval, there was little or no forgetting of trigrams from the start of the procedure. (remembered trigrams presented first, irrespective of interval length).

• These results can be explained in terms of proactive interference. The earlier memory for the consonants had entered into the long-term memory and was interfering with A the memory for the later consonants due to the similarity of info presented.

Cue Dependent:

Retrieval failure Forgetting, Tulving (1972)

• This is when we cannot access the memory (stored in LTM) until the correct retrieval cue is used. The memory/information is accessible, just not available.

• When we encode a new memory, we also store information that occurred around it, such as the way we felt or the place we were in. If we cannot remember or recall it, it could be because we are not in a similar situation to when the memory was originally stored.

• When we come into the same situation again, retrieval cues can trigger the memory of the situation.

• Encoding Specificity Principle' (Tulving) = "the greater the similarity between the encoding event and the retrieval event, the greater the likelihood of recalling the original memory." (more likely to recall info if in the same context as learning it).

Recall can depend on getting the right cues:

• Another theory of memory states that being able to recall a piece of information depends on getting the right cue. In this theory, forgetting is treated as a retrieval failure- the information still exists in memory but isn’t accessible.

• We have more chance of retrieving the memory if the cue is appropriate. Cues can be internal (e.g. your mood) or external (e.g. context, like surroundings, situation, etc.). We remember more if we are in the same context/mood as we were in when we coded the information originally. This is known as cue-dependent learning.

Godden and Baddeley (1975): Context-dependent forgetting

Aim:

• They investigated the effect of the environment on recall. This study took place in Scotland.

Method:

• 18 divers from a diving club were asked to learn lists of 36 unrelated words of two or three syllables

• 4 conditions:

  1. Learn on the beach- recall on the beach

  2. Learn on the beach- recall underwater

  3. Learn underwater- recall on the beach

  4. Learn underwater- recall under the water

Results:

1. 13.5

2. 8.6

3. 8.5

4. 11.4

Conclusion:

• The results show that the context acted as a cue to recall as the participants recalled more words when they learnt and recalled the words in the same environment than when they learnt and recalled the words in different environments

Weaknesses of Godden and Badelley’s study:

• This study has limited ecological validity because the environment was familiar to the diver's but the task was artificial (learning/recalling words underwater is an unrealistic task).

• Findings cannot be generalised to all cases of context cues as only divers were used.

• Another weakness is that the groups who learnt and recalled in different environments were disrupted (they had to change environments) whereas the groups who learnt and recalled in the same environment were not disrupted. This could have influenced their recall e.g time to rehearse or greater interference.

• However, it was a controlled experiment so it can be replicated so reliability can be tested.

Strengths of Godden and Badelley’s study:

• There is further support for the influence of contextual cues.

• Abernathy (1940) found that students performed better in tests if the tests took place in the same room as the learning of the material had taken place.

• The studies carried out do not take into account the meaning of the material and the level of motivation of the person when learning the information.

• Real-life applications:

• This is used as a strategy to improve recall in eye-witness memory when the witnesses are asked to describe the context in which the incident they have witnessed took place during cognitive interviews.

Goodwin et al (1969): State-dependent forgetting

Method:

• Forty-eight male medical students participated on day 1 in a training session and on day 2 in a testing. They were randomly assigned to four groups.

  • Group 1: (SS) was sober on both days.

  • Group 2: (AA) was intoxicated on both days.

  • Group 3: (AS) was intoxicated on day 1 and sober on day 2.

  • Group 4: (SA) was sober on day 1 and intoxicated on day 2.

• The intoxicated groups had 111 mg/100 ml alcohol in their blood They all showed signs of intoxication.

• The Participants had to perform 4 tests: an avoidance task, a verbal rote-learning task, a word-association test, and a picture recognition task.

Results:

• More errors were made on day 2 in the AS and SA conditions than in the AA or SS conditions, however, this was not the case for the picture recognition test. The SS participants performed best in all tasks.

Conclusion:

• This supports the state-dependent memory theory as the performance was best in the participants who were sober or intoxicated on both days.

Weaknesses of state-dependent forgetting:

• This study has limited ecological validity because the tasks performed by the participants were artificial therefore their performance might not reflect the way they would perform in everyday life.

• The participants knew that they were taking part in a study so they might have changed their behaviour (demand characteristics).

  • However, it was a controlled experiment so it can be replicated so reliability can be tested.

Strengths of state-dependent forgetting:

• There is further support for the influence of state-dependent cues. Miles and Hardman (1998) found that people who learned a list of words while exercising on an exercise bike remembered them better when exercising than at rest.

• The studies carried out do not take into account the meaning of the material and the level of motivation of the person when learning the information.

Real-life applications:

• This is used as a strategy to improve recall in eye-witness memory when the witnesses are asked to describe their mood/ emotional state when the incident they witnessed took place (cognitive interview).

Tulving and Psotka (1971)- Forgetting in LTM:

Method:

• Lulving and Potska compared the theories of interference and cue-dependent forgetting.

• Each participant was given either 1,2,3,4,5 or 6 lists of 24 words. Each list was divided into 6 categories of 4 words. Words were presented in category order, e.g. all animals, then all trees etc. After the lists were presented, in one condition, participants had to simply recall all the words- total free recall. In another condition, participants were given all the category names and had to try to recall words from the list- free-cued recall.

Results:

• In the total free recall condition, there seemed to be evidence of retroactive interference. Participants with 1 or 2 lists to remember had higher recall than those with more lists to remember had higher recall than those with more lists to remember, suggesting the later lists were interfering with remembering the earlier lists

• However, in the cued recall test, the effects of retroactive interference disappeared. It didn’t matter how many lists a participant had- recall was still the same for each list (about 70%).

Conclusion:

• The results suggest that interference did not cause forgetting. Because the memories became accessible if a cue was used, it showed that they were available but just inaccessible.

• Therefore, the forgetting shown in the total free recall was cue-dependent forgetting.

Evaluation:

• Tulving and Potska’s study was a laboratory experiment so it will have been highly controlled, reducing the effect of extraneous variables. However, laboratory experiments lack ecological validity as the setting and task are artificial. The study only tested the memory of words, so the results can’t reliably be generalised information of other types

As usual, the theory has strengths and weaknesses:

1. Cue-dependent forgetting is thought to be the best explanation of forgetting in LTM, as it has the strongest evidence. Most forgetting is seen to be caused by retrieval failure. This means that virtually all memory we have is available in LTM- we need the right cue to be able to access it.

2. However, the evidence is artificial (e.g. recalling word lists), lacking meaning in the real world. Also, it would be difficult, if not impossible, to test whether all information in LTM is accessible and available, and just waiting for the right cue.

3. The theory might not explain all types of memory. For example, cues might not be relevant to procedural memory, such as remembering how to ride a bike or play a musical instrument