Nature of Memory
Memory; is the process by which we retain information about events that have happened in the past.
Short term memory is for immediate events. The short term memory has a limited duration and a limited capacity. The way most people keep info in their STM for more than just a few seconds is to rehearse it. The result of (verbal) rehearsal is that Short-term memories are held in the STM and eventually become long-term.
Long term memory refers to memories that last from 2 hours to 100+. A long term memory store has potentially an unlimited capacity and duration. It's for the events that have happened in the past.
Evaluation! Peterson and Peterson study has been challenged. Might argue that participants are relying on more than just stm alone because they knew they were going to be asked to recall the items. Marsh et al suggested that when participants do not expect to be tested forgetting can occur after 2 seconds. More recent research suggests that it's not as short as petterson and petterson's study suggested, Narine et al found that items could be recalled after as long as 96 seconds. The same items were used to in her study whilst in the others different items were used causeing interference between items, decreasing recall. Therefore info remains in STM unless other info replaces it.
Capacity and Encoding
The capacity of STM can be assessed by using the digit span. In one of the earliest studies Joseph Jacobs used this technique to assess the capacity of STM, he found that average span for digits was 9.3 while it was 7.3 for letters. Jacob suggests it easier to recall numbers because there's only 9 whereas theres 26 letters. George miller reviewed psychological research and concluded the span of immediate memory is 7 (+- 2) people can recall 5words and 5 letters- we can chunk things together to remember more. Simon found that the size of the chunk effects how many chunks can be remembered. EVALUATION; Cowan reviewed a variety of studies and found that STM is likely to be limited to 4 chunks- STM may not be as extensive as we thought.
Encoding; informtation is changed so that it can be stored in memory. Info enters the brain via senses and then is stored in various forms such as visual, acoustic or semantic. Info in STM is mainly acoustically encoded. LTM tends to be semantically encoded. EVALUATION: in general STM appears to rely on acoustic code for storing info but some experiments have shown that visual codes are also used. Brandimonte et al found that Participants used Visual encoding when they were given a visual task and prevented from doing any verbal rehersal in the retention interval. Other research has shown that sometimes we use semantic coding; Wickens et al. Research has also shown LTM is nor exclusively semantic; Frost showed that long term recall was related to visual as well as semantic categories, Nelson and Rhothbart found evidence of acoustic encoding.
Multi Store Model
The multi store model of memory is and explanation of how memory precesses work. The MSM was first described by Richard Atkinson and Richard Shiffrin in 1968. Componennts of the MSM; sensory memory- actually composed of several stores (the senses) The sensory stores are constantly receiving info but most of this receives no attention. If a sensory store receives attention the data is transferred to STM. Attention is the first step in remembering something. Short-Term Memory- info held int the STM is in a fragile state, it will decay quickly if it isn't rehearsed. It will aslo disappear if new info enters the STM displacing the original info. This happens because it has a limited capacity. Long-Term Memory- Second step is moving info from STM to LTM, Atkinson and Shiffrin said this also happens through rehearsal. Rehearsal maintains info in the STM but the more it's rehearsed the more lasting the memroy will be. This is known as maintenance rehersal. Evidence For 3 Seperate Memory Stores; The sensory Store- Sperling gave evidence to support the limited duration of the sensory store. He found that individuals recalled 3 itmes better than 5, this shows the rapid decay in info in the sensory store. The serial position effect; Glanzer and Cunitz gave support fot the distinction between the STM and LTM. They remembered words from the beginning of the list (primacy effect) and words from the end of the list (recency effect) . Primacy occurs because they are best rehearsed and transferred to LTM, recence occurs because these words are in STM when they start to recall. Areas of the Brain associated with STM & LTM; Research by Beardsley showed the prefrontal cortex is active when working on STM tasks, Squire et al found the hippocampus is active with LTM.
Evaluating the Multi- Store Model
Strengths; there is strong evidence of three qualitatively different stores. The model provides an account of memory in terms of both structures and process. It also has clear predictions about memory which means psychologists can conduct studies to test it. Limitations; The main criticism of the MSM is that is oversimplifies memory structures and processes. The msm suggests that STM and LTM each operate in a single uniform fashion whereas evidence suggests that this is not true. Evidence for a non-unitary STM came from the case study of KF. The case suggests that STM is not a single store. MSM describes LTM as one single store whereas evidence from patients with amnesia indicates that there are diff kinds of long-term. Schachter et al have suggested that there are four long-term stores; SEMANTIC- memory for knowledge about the world EPISODIC- memory for what you did yesterday or a ilm you saw last week PROCEDURAL memory for riding a bicycle or learning how to read PERCEPTUAL memory related to perceptual priming. Spiers et al studied 147 patients with amnesia, procedural and perceptual systems were intact but other two werent. LTM is not utianry. Craik et al proposed that processing and rehearsing are different and that things that are processed more deeply are more memorable because of the way they are processed (shallow, phonemis and semantic processing.) Logie pointed out that the STM relied on the LTM and therefore cannot come first as suggested by the MSM. Ruchkin et al demonstrated this and concluded STM is a part of the LTM thats activated,
The Working Memory Model
The working memory model addresses one aspect of memory- sort term (imediate memory). Baddeley and Hitch used the term working memory to refer to that bit of memory that you are using when you are working on a complex task which requires you to store info as you go along. Baddeley and Hitch felt that the STM was not just one store but a number of different stores. Components of Working Memory; Central Executive- the function is to direct attention to a particular task, determines how resources are allocated- these are the three slave systems. Data arrives from senses or LTM. It has a very limited capacity and can't attend to too many things at once. Phonological Loop- deals with auditory info and preserves the order of it. Baddeley further subdivided the loop into phonolgical store and articulatory process. P.S hold the words you hear and the A.P is used for words that are heard or seen. Has a limited capacity. Visuo-spatial Sketchpad- used when you have a spatial task. Visual info is what things look like, spatial info is the relationship between things. Logie suggested it can be divided into a visual cache (store) and and innet scribe which deals with spatial relations. Episodic buffer- Baddeley added it recently because he realised it required a general store. It's and extra storage system that has limited capacity. Intergrates info from the central executive, phonological loop and visuo spatial sketchpad and long term memory.
2tasks using same/different components; Hitch and Baddeley gave two tasks. task one was slower when given a task ivolving both the centeral executive and the articulatory loop. Task 1 was the same whether using articulatory loop or no extra task. Shows that doing two tasks involve the same component causes difficulty. Also suggests that when diff components are used performance is not affected. Evidence fo the central Executive; Bunge et al used fMRI to see which parts of he brain were most activve where participants were doign two tasks. Same brain areas were active in either dual or single task condition but significantly more activation in the dual task condition. Evidence for Phonological Loop & Articulatory Process; phonolgical loop explains why the word length effect occurs- better remembering short words rather than long words (holds the amount of info you can say in 2seconds) Baddeley et al. Makes it harder to remember list of long words than short worfdds, long words can't eb rehearsed on phonolgical loop because they dont fit. Word length effect disappears if a person is given an articulatory suppression task- such tasks tie up the articulatory process and means u cant rehearse shorter words more quickly than longer ones. Evidence for Visuo-spatial sketchpad; Baddeley et al demonstrated the existence of the Visuo-spatial sketchpad. Participants were given a visual tracking task. At the same time they were given one or two other tasks. Task 1 was difficult but task 2 was better because it involved 2 other slave systems. Evidence for episodic buffer; Baddeley et al found that when participants were shown words and then asked for immediate recall their performance was better for related words than unrelated. Supports the idea of an immediate memory store thats no visual or phonological.
Evaluation of Working Memory Model
Strengths; explanatory power-explains many psychological observations. Includes the word length effect and the partial short memory difficulties experienced by people with brain damage (KF and SC). Supporting evidence- Considerable amount of supporting evidence for the model. Especially true about more recent studies. Different kinds of memory-working memory model represents a shift in our understanding of memory as one activity, to being able to distinguish an array of diff kinds of memory. In 1950's psychologists tried to find where memory was located in the brain. Comparison with MSM- abundent eidence of a brief memory store and the WMM offers a better account of the STM component of the MSM. WMM includes erbal rehersal as an optional proccess rather than an only means.WMM also emphasises process more than the MSM. Limitations; Central executive- concer about it because it's too vague and doesn't explain anything. Critics feel that there are probably several components. Eslinger and Damasio studied EVR who had a cerebral tumor removed; performed well on tests requiring reasoning (suggested central executive was intact) however had poor decision-making skills (suggesting his central executive was not wholly intact. Central executive is unsatisfactory because it fails to explain anything, more complex than currently represented. Evidence from brain-damaged patients- some of the key evidence comes from case studies of individuals who have suffered from brain damage. Cannot make before and after comparisons of these indiiduals and so its not clear the behaviour are cause by the damge. The process of brain injury is traumatic which may cause the change in behaviour.
a cognitive interview is a police technique for interviewing witnesses which encourages them to recreate the original context in order to increase the accessibility of stored info . Memories are accessed using multiple retrieval strategies. Fisher and Geiselman reviewed the relevant psychological lit on memory and related this to the way interviews are carried out by policemen in real life. Fisher and Gieselman developed the cognitive interiew technique concerning effective memory recall. It's characterised by 4 components; Report everything- interviewer encourages the reporting of every detail. Mental reinstatement of original context- encourages interviewee to mentally recreate environment and people. Changing order- interviewer may try alternative ways through the timeline of the incident. Changing perspective-interviewee is asked to recall the incident from multiple perspectives. Evaluation; Milne and Bull (2002) examined the effectiveness of each of the four components of the CI, undergraduates and children were interviewed using just one of the components and compared to a control condition . Recall was broadly similair and no different to the control group, however when using a combination of the components recall was significantly higher. Difficulties establishing effectiveness; One of the problems with evaluating the effectieness of the CI is that it is no longer just one procedure but a collection of procedures. Some police forces only use part of the technique (Kebbell and Wagstaff 1996) From interviews with police Kebbell and Wagtaff reported a time problem with the CI, the technique requires more time than is often available, and so they prefer to use deliberate strategies to limit eyewitness report to minimize the info police feel is neccessary.
MNEMONIC TECHNIQUES; any structured technique that is used to help people remember and recall info. We use these techniques when we have to recall large amounts of info or to make associations. VERBAL MNEMONICS; a variety of memory improvement techniques on words. An acronym is a word or sentence formed from the initial letter of other words. An acrostic is a poem or sentence where the first letter in each line or wordforms the item to be remembered. Rhymes are groups of words with an identity and rhythm. Chunking involves dividing a long string of info into memorable chunks. VISUAL IMAGERY MNEMONICS; the best known method is Loci, a technique which is used to remember points, Loci literally means Places and the method requires the learner to associate parts of the material with different places, Another more recent method is the Keyword Method (Atkinson and Raugh 1975) used trying to associate two places of info. Many other techniques that use visual imagery such as spider diagrams, mind maps. Involve making notes of info in the form of drawings, usually in a branching pattern. This kind of process adds a range of visual cues to the verbal material, has also been called mind mapping (Buzan 1993)
Memory Improvement Evaluation
Research on Verbal Mnemonics; Gruneberg (1973) demonstrated the popularity of Verbal Mnemonics in real-life. He gave a survey to psychology students and 30% used mnemonics in their revision, verbal mnemonics was most popular. Gidden et al (1983) found verbal mnemonics were effective in children with learning disabilities, effectiveness over the control group no longer evident after 12 months later. Research on Visual Mnemonics; effectiveness of the method Loci has been demonstrated in a wide variety of studies. O'Hara et al (2007) found that training in the use of mnemonic techniques such as Loci has long-term benefits for older adults, particularly those who continued to use this technique. Research on the Keyword method has produce mixed results, Atkinson (1975) found that participants who used the keyword effect in learning russian learnt siginificantly more than the controlled group but long term effects is less-well supported. Limitations of Mnemonic Strategies; The limitations on this research is that most studies have taken place in comparitively artificial environments using material that is believed to be especially appropriate for the mnemonic strategies under test. Real-life classroom studies of the techniques show more mixed results. e.g.g though they have been proves successful in teaching a new language they have yet to be shown to be effective when students are actually speaking foreing languages (slavin 2005)