Memory Paper 1

• Coding, capacity and duration of memory

  Capacity - the amount of info that can be held in memory store.

  Duration - the length of time info can be held in memory store

  Coding- The format in which info is stored in various memory stores.

  Short term memory- limited capacity memory store. In STM, coding is mainly acoustic, capacity is between 5 and 9 items on average, duration is about 18 seconds

  Long term memory- The permanent memory store. In LTM, coding is mainly semantic, it has unlimited capacity and can store memories for up a lifetime.
• Research on Coding


  Alan Baddeley 1966 gave different lists of words to 4 groups. Group 1- acoustically similar e.g. cat, canGroup 2- acoustically dissimilar e.g. pit, fewGroup 3- semantically similar - (meanings) great, large,Group 4- semantically dissimilar- e.g. good, huge, hotPpts were shown original words and asked to recall them in the correct order. When they did this task immediately, recalling from STM, they tended to do worse with acoustically similar words. When they recalled the word list after a time interval of 20 mins recalling from LTM, they did worse with semantically similar words. Findings suggest that info coded acoustically in STM and semantically in LTM
• Research in capacity


  Digit span- how much info can hold at one time. Jacob 1887- found out capacity by measuring digit span. researcher reads out 4 digits and the ppts recall these loud in correct order. If this is correct, researcher reads out 5 digits and so on until ppt cannot recall the order correctly. Indicates individual's digit span. Jacob found that mean span for digits across all ppts was 9.3 items. mean spam for letters- 7.3Span of memory and chunking - Miller made observations 1956, eg noted that things come in sevens, days of week, seven notes, deadly sins. He thought that span of STM was 7 items but plus/minus two. But also noted that people can recall 5 words easily as they can recall 5 letters. We do this by chunking.
• Research on duration


  Duration of STM- Peterson and Margret 1959 tested 24 students in 8 trials each. Each trial they were given consonant syllable and 3 digit number. Student counted backwards from this number until told to stop (to prevent any mental rehearsal of the syllable) on each trial told to stop after varying periods of time, After 3 seconds average recall was 80%, after 18 seconds it was about 3%

  Peterson's findings suggested that STM duration may be about 18 seconds, unless we repeat info over and over.
• Duration of LTM


  Barick 1975, studied 392 American ppts 17-74 years. High school year books were obtained and recall was tested in various ways: photo recognition its consisting of 50 photos. Free recall test where ppt recalled all names of their graduating class. Ppts tested within 15 years of graduation were about 90% accurate in photo recognition, after 48 years recalled declined to 70% for photo recognition. Free recall was less accurate than photo recognition. Shows LTM may last up to a lifetime for some material
• Evaluation of Baddeley's study - Strength


  Separate memory stores, clear difference between 2 memory stores. Later research showed that there are some expectations to Baddeley's findings. But the idea that STM uses mostly acoustic coding and LTM mostly semantic has stood the test of time. This was an important step in our understanding of the memory system, which led to the multi store model.
• Limitation


  Artificial stimuli was used rather than meaningful material. for example, the word lists had no personal meaning to ppts. So Baddeley's findings may not tell us much about coding in different kinds of memory tasks especially in everyday life. When processing more meaningful info, people may use semantic coding even for STM tasks. Suggests that the findings from this study have limited application.
• Evaluation on Jacob's study- Strength


  A valid study, been replicated. Very old study and early research in psychology often lacked adequate controls. For example, some ppts digit spans might have been underestimated because they were distracted during the test - cofounding variable. Despite this, Jacob's findings have been confirmed by other, better controlled studies. Suggests that Jacob's study is a valid test of digital span in STM.
• Limitation


  Not so many chunks. Miller's research is that he overestimated STM capacity. Cowan 2001, reviewed other research and concluded that the capacity of STM is only about 4 plus/minus 1 chunks. Suggests that the lower end of Miller's estimate 5 items is more appropriate than seven items
• Evaluation on Peterson's study

  One limitation- the stimulus material was artificial. The study was not completely irrelevant because we do sometimes try to remember fairly meaningless material - phone numbers. Even so, recalling consonant syllables does not reflect most everyday memory activities where what we are trying to remember is meaningful. Mean study lacked external validity
• One strength- Bahrick's study


  High external validity. This is because the researchers investigated meaningful memories (people's names and faces). When studies on LTM were conducted with meaningless pictures to be remembered, recall rates were lower - (Shepherd 1967). This suggests that Bahrick et al findings reflect more real estimate of the durations of LTM
• Types of long memory


  Tulving 1985 was one of the first cognitive psychologists to realise that the multi store model's view of long term memory was too simplistic and inflexible. Tulving proposed that there are 3 LTM stores.
• Episodic memory


  Refers to our ability to recall events from our lives. e.g. a diary a record of our personal experiences. these memories are complex. they are time-stamped . Thye also store info about how events relate to each other in time. Your memory of a single episode will include several elements such as people, places, objects. All these memories are interwoven to produce a single memory. You have to make conscious effort to recall episodic memories. You do this quickly but are still aware that you are searching for your memory of what happened when you went to the dentist for instance.
• Semantic memory


  This store contains our shared knowledge of the world. It has been likened to the combination of encyclopaedia and dictionary. knowledge such as how to apply to university. These memories are not time-stamped. We don't usually remember when we first heard about the frozen film. Semantic knowledge is less personal and more about the facts we share. Contains an immense collection of material which given its nature is constantly being added too. Tulving says it is less vulnerable to distortion and forgetting than episodic memory.
• Procedural memory


  Our memory for actions or skills or how do things. We can recall these memories without conscious awareness or much effort. A good example is driving a car. Our ability to do this becomes automatic through practice. We change gear without having to recall how. These sort of skills may find it hard to explain to someone else becomes a difficult task.
• Evaluation of LTM - Strength


  Clinical evidence- Episodic memory in both Clive and Henry was severely impaired due to brain damage. But their semantic memories were relatively unaffected. They still understood the meaning of the words. HM could not recall stroking a dog half an hour earlier but didn't need to have the concept of a dog explained to him. There procedural memories were also intact. Both knew how to speak and walk and Clive was a professional musician and can play piano and read music. Supports Tulving's s view that there are different memory stores in LTM- one store can be damaged but other stores can be unaffected.
• Another strength


  Real world application- as people age they go through memory loss. But research has shown this seems to be specific to episodic memory- it becomes harder to recall memories of personal events/experiences that occurred relatively recently through past episodic memories remain intact. Belleville 2006- devised an intervention to improve episodic memories in older people. The trained ppts performed better on the test of episodic memory after training than a control group. Shows that distinguishing between types of LTM enables specific treatments to be developed
• One limitation

  Clinical studies aren't perfect- lack of control variables/ Brain injuries experienced by ppts were usually unexpected. Researcher had no way of controlling what happened to the ppt before or during an injury. The researcher has no knowledge of the individual's memory before the damage. Without this it is difficult to judge exactly how much worse it is afterwards. This lack of control limits what clinical studies can tell us about different types of LTM.
• Another limitation on types of LTM


  Conflicting neuroimaging evidence - Randy and Peterson 1996- reviewed evidence regarding the location of semantic and episodic memory. They concluded that semantic memory is located in the left of the prefrontal cortex and episodic memory on the right. However other research links left prefrontal cortex with encoding of episodic memories and right prefrontal cortex with episodic retrieval. This challenges any neurophysiological evidence to support types of memory as there is poor agreement on where each type might be located.
• The working model


  - a representation of STM and suggests that STM is a dynamic processor of different types of info using subunits co-ordinated by a central decision-making system

  WMM is concerned with the mental space that is active when we are temporarily storing and manipulating info e.g. when playing chess or comprehending language. Model consists of 4 components.
• Central executive


  - has supervisory role and monitors incoming data focuses and divides our limited attention and allocates subsystems to tasks. It has very limited processing capacity and does not store info
• Phonological loop


  it deals with auditory info and preserves the order in which info arrives. It's subdivided into- phonological store- which stores the words you hear

  Articulatory process- allows Maintenace rehearsal. the capacity of this loop is 2 seconds worth of what u say.
• visuo-spatial sketchpad


  stores visual and spatial info when required. for example, if you are asked to work out how many windows there are in your house you visualise it. Has limited capacity which according to Baddeley 2003- is about 3 to 4 objects . Robert subdivided the VSS into- visual cache- which stores visual data

  Inner scribe- which records the arrangement of objects in the visual field.
• Episodic buffer

  added to model by Baddeley. Temporary store for info integrating the visual, spatial and verbal info processed by other stores and maintaining a sense of time sequencing - basically recording events that are happening. can be seen as a storage component of the central executive and has limited capacity about 4 chunks. This episodic buffer links working memory to long term memory and wider cognitive processes such as perception
• Evaluation- one strengthof WMM


  clinical evidence- support from Tim Shallice and Elizabeth Warrington case study of patient KF. After brain injury, KF had poor STM ability for auditory info but could process visual info normally. For instance, his immediate recall of letters and digits was better when he read them than when they were read to him. KF's phonological loop was damaged but his visuo-spatial sketchpad was intact. This finding strongly supports the existence of separate visual and acoustic memory stores.
• Another strength

  Dual task performance - when Baddeley's ppts carried out visual and verbal task at the same time, their performance on each was similar when they carried out the tasks separately. But when both tasks were visual or both verbal, performance on both declined substantially. Because both visual tasks compete for the same subsystem, whereas there is no competition when performing a verbal and visual task together. This shows there must be a separate subsystem that processes visual input.
• One limitation


  unclear whether KF had other cognitive impairments apart from his damage to his phonological loop which might have affected his performance on memory tasks. For example, his injury was caused by a motorcycle accident. The trauma involved may have affected his cognitive performance quite apart from any brain injury. Challanges the evidence that comes from clinical studies of people with brain injuries that may have affected many different systems.
• Another limitation


  Natural of central executive- there is a lack of clarity over the nature of the central executive. Baddeley himself recognised (2003) this when he said the CE is the most important but least understood component of working memory. The CE may consist of separate subcomponents. This means that the CE is an unsatisfactory component and this challenges the integrity of the WMM.
• Explanations for forgetting- Retrieval failure


  Retrieval failure- form of forgetting. Occurs when we don't have the necessary cues to access memory. the memory is available but not accessible unless suitable cue provided.Cue- trigger of info that allows us to access a memory. Such cues may be meaningful or may be indirectly linked by being encoded at the time of learning, they may be external or internal.
• Encoding specificity principle


  This states that a cue (if helpful) has to be both present at encoding and present at retrieval. But if the cue available at encoding and retrieval are different there will be some forgetting. Some cues are encoded at the time of learning in a meaningful way e.g. cue for STM, such cues are used in many mnemonic techniques and other cues encoded at learning but not in meaningful way. 2 examples are: Context dependent forgetting - recall depends on external cue e.g. weather/place State-dependent forgetting- recall depends on internal cue e.g. feeling upset, drunk
• Research on context dependent forgetting


  Godden and Baddeley 1975 studied deep sea divers to see if training on land helped or hindered their work underwater. Divers learnt a list of words either underwater or land with 4 conditions eg learn on land- recall on water.
• Findings and conclusions


  2 of the conditions e.g. learn in land-recall on land, environmental context on learning and recall matched whereas in the other two they did not. Accurate recall 40% lower in non-matching conditions.Concluded that external cues available at learning were different from the ones available at recall and this led to retrieval failure.
• Research on State-dependent forgetting


  procedure- Cater and Cassaday 1998 gave antihistamine drug to ppts and had mild sedative effect making ppts slightly drowsy. This creates an internal physiological state different from normal state of being awake, alert. The ppts had to learn list of words and passages of prose and recall info in 4 conditions e.g. learn on drug- recall when not in drug.
• Findings


  Conditions where there was mismatch between internal state at learning and recall performance on memory test was significantly worse so when cues are absent then there is more forgetting.
• Evaluation- One Strength

  Real world application- retrieval cues can help to overcome some forgetting in Everday situations. Although cues may not have a very strong effect on forgetting. Baddeley suggests they are still worth paying attention to. e.g. going from one room and to another to get something but then suddenly forget when arrived in another room but when you go back you remember. When we have trouble remembering something it is better to recall in the environment, we learnt it first. Shows how research can remind us strategies we use in the real world to improve our recall.
• Another strength


  Research support- impressive range of research that supports retrieval failure explanation. Studies by Godden and Baddeley and Carter are just two examples because they show that lack of relevant cues at recall can lead to context and state dependent forgetting in everyday life. Micheal and Mark 2010- argue that retrieval failure is the main reason for forgetting in long term memory. Evidence shows that retrieval failure occurs in real world situations as well as in the highly controlled conditions in the lab.
• One limitation


  Baddeley argue that context effects are actually not very strong especially in daily life as different contexts have to be very different indeed before an effect is seen. e.g. it would be hard to find an environment that would be as different from land and water. In contrast learning info in one room and recall in different room is unlikely to be result in much forgetting as these environments aren't different enough. Means retrieval failure due to lack of contextual cues may not actually explain much everyday forgetting.
• Another limitation


  Recall versus recognition- context effects may depend substantially on the type of memory being tested. Godden and Baddeley 1980 replicated in their underwater experiment but used recognition test instead of recall- ppt had to say whether they recognise the word from the list instead of retrieval themselves. When recognition was tested there was no context dependent forgetting because it only applies when a person has to recall info rather than recognise it.
• Factors- affecting accuracy of eyewitness testimony- misleading info


  eyewitness testimony- ability of people to remember the details of events, such as accidents and crimes which themselves have observed, accuracy of EWT can be affected by factors such as misleading info and anxiety.
• Lotfus and Palmer 1974 arranged for 45 participants to watch clips of car accidents and asked questions about it.