Memory Flashcards
Short and long term memory
Duration: Testing STM was artificial: Trying to memorise consonant syllables does not truly reflect most everyday memory activities where what we are trying to remember is meaningful. However, we do sometimes try to remember fairly meaningless things, such as group of numbers (phone numbers) or letters (post codes). This means that the study does have some relevance to everyday life.
Duration STM results may be due to displacement: In the Peterson’s study participants were counting the numbers in their STM and this may displace or overwrite the syllables to be remembered. Reitman (1974) used auditory tones instead of numbers so that displacement wouldn’t occur (sounds don’t interfere with verbal rehearsal) and found that the duration of STM was longer. This suggests that forgetting in the Peterson’s study was due to displacement rather than decay, and was not measuring the duration of STM. Nairne et al (1999) found that items could be recalled after as long as 96 seconds.
Coding: Baddeley may have not tested LTM: STM was tested by asking participants to recall a word list immediately after hearing it. LTM was tested by waiting 20 minutes. It is questionable to wether it was really testing LTM.
STM may not be exclusively acoustic: In general, STM appears to rely on acoustic coding for storing information. However, some experiments have shown that visual codes are also used in STM. For example, Brandimote et al (1992) found participants used visual coding in STM if they were given a visual task and prevented from doing any verbal rehearsal in the retention interval before performing a visual recall task. Normally we ‘translate’ visual images into verbal code in STM, but as verbal rehearsal was prevented participants used visual codes.
Coding: LTM may not be exclusively semantic: In general LTM appears to be semantic but as with STM, this may not be always true. Frost (1972) showed that long term recall was related to visual as well as semantic categories, and Nelson and Rothbart (1972) found evidence of acoustic coding in LTM. Therefore it seems that coding in STM or LTM is not simply acoustic or semantic but can vary according to circumstances.
Capacity: capacity of STM may be more limited, one criticism is Miller’s original findings have not been replicated. Cowan (2001) found likely to be limited to about four chunks, lower range of Miller’s range is more appropriate (7-2). This suggests STM may not be as extensive as was thought.
Capacity: individual differences, not the same for everyone. Jacobs found that recall (digit span) increased with age. 8 year olds could remember 6.6 digits, whereas mean for 19 year olds was 8.6 digits. This age increase might be due to changes in brain capacity and or development of strategies. Therefore, capacity is not fixed and individual differences may play a role.
The multi store model of memory
STRENGTHS: supporting evidence: Controlled lab studies on capacity, duration and coding support the existence of a separate short and long term store, which is the basis of MSM. Studies using brain scanning techniques have also demonstrated that there is a difference between STM and LTM. Beardsley (1997) found that the prefrontal cortex is active during STM but not LTM tasks. Squire et al (1992) also used brain scanning and found the hippocampus is active when LTM is engaged.
STRENGTHS: Case studies: Psychologists have also shown that different areas of the brain are involved in STM and LTM from their study of individuals with brain damage. One case involved a man referred to as HM (Scoville and Milner, 1957). His brain damage was caused by an operation to remove the hippocampus from both sides of his brain to reduce the severe epilepsy he had suffered. HM’s personality and intellect remained intact but he could not form new LTMs, although he could remember things from before the surgery.
LIMITATIONS: the multi-store model is too simple: The MSM suggests that both STM and LTM are single unitary stores. However, research does not support this. Research shows there are different kinds of LTM and STM and each behaves differently.
LTM involves more than maintenance rehearsal: Craik and Lockhart (1972) suggested that enduring memories are created by the processing you do, rather than through maintenance rehearsal; things that are processed more deeply are more memorable just because of the way they are processed.
The working memory model
STRENGTHS: dual task performance: The main reason for developing the WMM was to account for dual task performance. Hitch and Baddeley (1976) supported the existence of the central executive in one such study. Task 1 occupied the central executive (participants were given a statement B is followed by A and shown two letters such as AB and asked to say true or false. Task 2 involved the articulatory loop (asked to say the the the repeatedly) or involved both the central executive and the articulatory loop (saying random digits). Task 1 was slower when task 2 involved both the central executive and the articulatory loop. This demonstrates the dual task performance effect and shows that the central executive is one of the components of working memory.
STRENGTHS: evidence from brain damaged patients: Studies of individuals with brain damage also support the WMM. Shalice and Warrington (1970) studied a man called KF whose short term forgetting of auditory information was much greater than that of visual stimuli. In addition his auditory problems were limited to verbal material such as letters and digits but not meaningful sounds (phone ringing). Thus his brain damage seemed to be restricted to the phonological loop. Another patient SC had generally good learning abilities with the exception of being unable to learn word pairs that were presented out loud. This suggests damage to the phonological loop. Another patient, LH who had been involved in a road accident performed better on spatial tasks than those involving visual imagery.
LIMITATIONS: the central executive: CE allocates resources and is essentially the same as ‘attention’. Some psychologists feel this is too vague and doesn’t really explain anything. Eslinger and Damasio (1985) studied EVR, who had had a cerebral tumour removed. He performed well on tasks requiring reasoning, which suggested that his CE was intact, however he had poor decision making skills which suggests his CE was not wholly intact.
LIMITATIONS: evidence from brain damaged patients: some of the key evidence for the WMM comes from case studies of individuals who have suffered serious brain damage. There are a number of problems with using such evidence. First of all, the process of brain injury is traumatic, which may in itself change behaviour so that a person performs worse on certain tasks. Second, such individuals may have other difficulties such as difficulties paying attention and therefore underperform on certain tasks.
Types of long term memory
Evidence from brain scans: The distinction made between the 3 kinds of memory is supported by research using brain scanning techniques. Such research shows that different areas of the brain are active when different kinds of LTM are active. Episodic memory is associated with the hippocampus and other parts of the temporal lobe where the hippocampus is located. Episodic Memory is also associated with activity in the frontal lobe. The memories of the different elements of the particular event may be distributed in other areas of the brain but they are all connected together by the hippocampus to form an episode. Semantic memory also relies on the temporal lobe. Procedural memory activation is associated with the cerebellum, which is involved in the control of fine motor skills as well as the motor cortex
Distinguishing procedural and declarative memories: HM couldn’t form new LTMs as this was affected by the destruction of his hippocampus but he retained pre-existing LTMs. After surgery, HM could still form new procedural memories but not episodic or semantic.
Distinguishing episodic and semantic memories: The relationship between episodic and semantic memories leaves you questioning wether episodic memories are a gateway to forming semantic memories or wether semantic memories can be formed independently. Studying patients with Alzheimer’s, some patients retain the ability to form new episodic memories but not semantic. This alone is not sufficient evidence that the two are distinct because it could be that episodic memory places greater general demands on mental processing and that’s why its more affected by brain damage. This suggests episodic memories may be a gateway to a semantic memory but it is possible to form semantic memories separetely.
Explanations for forgetting: interference
Research is quite artificial: Most of the research has been lab-based and often used rather artificial lists of words and/or nonsense syllables. Thus findings may not relate to everyday use of memory, which tends not to involve word lists. In addition, participants may lack motivation to remember the link in such studies and this may allow interference effects to appear stronger than they really are. In other words, the research is low in ecological validity.
Interference only explains some situations of forgetting: The issue appears to be that, while interference effects do occur in everyday life, they don’t occur often. Rather special conditions are required for interference to lead to forgetting- the two memories need to be quite similar. It is for this reason that interference is considered to be a relatively unimportant explanation for forgetting. Anderson (2000) concluded that there is no doubt that interference plays a role in forgetting, but how much forgetting can be attributed to interference remains unclear.
Accessibility versus availability: Researchers have often questioned wether interference effects actually cause a memory to disappear or wether the effects are temporary. Ceraso (1967) found that, if memory was tested again after 24 hours, recognition (accessibility) showed considerable spontaneous recovery, whereas recall (availability) remained the same. This suggests interference occurs because memories are temporarily not accessible rather than actually being lost (unavailable).
Individual differences- individuals with a greater WMM span were less susceptible to proactive interference (Kane and Engle 2000). Tested this by giving 3 word lists to learn, those with low WMM span showed greater proactive interference when recalling 2nd and 3rd lists than those participants with higher span. Highlights individual differences play a role in interference effects.
Accuracy of EWT: misleading information
Supporting evidence: There has been considerable support for research on the effect of misleading information. Lotus conducted a study involving a cut out of bugs bunny (Braun et al 2002). College students were asked to evaluate advertising material about Disneyland. Embedded in this material was misleading information about either bugs bunny or aerial (neither could be seen at Disneyland because Bugs is not Disney and Aerial hadn’t been introduced at the time of their childhood). Participants were assigned to Bugs, Aerial or a control condition (no misleading information). Participants in Bugs or Aerial group were more likely to report having shaken hands with these characters than the control group. This shows how misleading information can create an inaccurate/false memory.
EWT in real life: Loftus’ research suggested that EWT was generally inaccurate and therefore unreliable. Lab experiments may not represent real life because people don’t take the experiment seriously and are not emotionally aroused in the way they would be in a real life accident. Foster et al (1994) found that, if participants thought they were watching a real life robbery, and also thought that their responses would influence the trial, their identification of a robber was more accurate. Yuille and Cutshall (1986) also found evidence of greater accuracy in real life. Witnesses to an armed robbery in Canada gave very accurate reports of the crime four months after the event even thought they had initially been given two misleading questions. This suggests misleading questions may have less influence on real life EWT.
Real world application: a strength is this can be applied to the criminal justice system, which relies heavily on EWT for prosecuting crimes. This research has been used to warn the justice system of problems with eyewitness identification. This demonstrates the importance of EWT in helping ensure that innocent people are not convicted of crimes that they did not commit on the basis of faulty EWT.
Individual differences- elderly people have difficulty remembering the source of their information even if their memory for the information is unimpaired. As a result, they become more prone to the effect of misleading information when giving testimony. Therefore, individual differences are important factor when assessing the reliability of EWT.
Accuracy of EWT: Anxiety
Weapon focus may not be caused by anxiety: Pickel (1998) proposed that the reduced accuracy of identification due to the weapon focus effect could be due to surprise rather than anxiety. This was tested by participants watching a thief enter a hairdressing salon carrying scissors (high threat, low surprise), handgun (high threat, high surprise) wallet (low threat, low surprise) or a whole raw chicken (low threat, high surprise). Identification was least accurate in the high surprise conditions rather than high threat. This supports the view that the view weapon focus effect is related to surprise rather than anxiety.
Real life VS lab studies: One of the strengths of the study by Christianson and Hubinette was that it was a study of anxiety in the context of a real crime. It may well be the case that lab studies do not create the real levels of anxiety experienced by a real eyewitness during an actual crime. Deffenbacher et al (2004) agree with this but found, from a review of 34 studies, that lab studies in general demonstrate that anxiety leads to reduced accuracy and that real life studies are associated with an even greater loss in accuracy, which is at odds with the result from Christianson and Hubinette.
No simple conclusion: The study of Christianson and Hubinette concerned a violent real life crime. Many other studies of anxiety and accuracy of identification, even the real life ones, did not involve violence. Like Christianson and Hubinette, Halford and Milne (2005) found that victims of violent crimes were more accurate in their recall of crime scene information than victims of non-violent crimes. This shows that there is no simple rule about the effect of anxiety on accuracy of EWT>
Improving accuracy of EWT: the cognitive interview
Research into the effectiveness of the cognitive interview: A meta-analysis of 53 studies, found on average, an increase of 34% in the amount of correct information generated in the CI compared with the standard interviewing technique. Köhnken et al (1999) although most of these students involved volunteer witnesses tested in a lab. However, the effectiveness of the CI may be due more to some individual elements rather than the whole thing. Milne and Bull (2002) interviewed undergraduate students and children using just one individual component of the CI, and compared the responses gathered to a control condition. Recall across each of the four individual components was broadly similar and no different from that of the control group. When participants were interviewed using a combination of ‘report everything’ and ‘mental reinstatment’ components of the CI, their recall was significantly higher than in other conditions.
Quantity VS quality: The procedure is designed to enhance the quantity of correct recall without compromising the quality. Köhnken et al (1999) found an 81% increase of correct information but also a 61% increase of incorrect information when the enhanced CI was compared to a standard interview. This means that police need to treat all information collected from CIs with caution. It does not guarantee accuracy.
Problems with using the CI in practice: From interviews with police, Kebbell and Wagstaff report a problem with the CI in practice. Police officers suggest that this technique requires more time than is often available and that instead they use a deliberate strategies aimed to limit an eyewitness’ report to the minimum amount of information that officers feel is necessary. In addition, CI requires special training and many forces have not been able to provide more than a few hours. For these reasons the use of CI had not been widespread.
Explanation for forgetting : retrieval failure
Research support: Tulvig and Pearlstone power of retrieval cues, counteract this saying research is artificial
However, retrieval cues do not always work: The issue is that information you are learning is related to a lot more than just the cues. This has been called the outshining hypothesis: a cue’s effectiveness is reduced by the presence of better cues. According to Smith and Vela (2001) context effects are largely eliminated when learning meaningful material. This is not to say retrieval cues are irrelevant to memory- there are many instances where they explain everyday forgetting- but they don’t explain everything.
RWA: improves recall when you need to, for examples an exam. Golden and Baddeley claim u need to be in the same context, however Smith (1979) just thinking of the room where you did the original learning (mental reinstatmtn ) was as effective as actually being in the same room. This shows how research into retrieval failures can suggest tragedies for improving recall in real world situations such as exams or EWT.
