Memory

Memory

1. Coding, Capacity and Duration of memory

   • Coding = BADDELEY - gave lists of words to four groups of ppts
     • Acoustically similar = cat,cab,can
     • Acoustically dissimilar = dog, car, ptoato
     • Semantically similar = big, large, great
     • Semantically dissimilar = good, huge, cold
     • Ppt's were shown the words and asked to recall them in order. When they were asked to do this immediately after hearing the words (STM), they tended to do worse in the acoustically similar words. If ppt's recalled them 20 mins after (LTM), they did worse with the semantically similar words
     • He concluded from the results that information in the LTM is coded semantically
     • Artificial stimuli = used articifical stimuli instead of meaningful information. No meaningful or personal relavence to ppt's. Should be cautious about generalising the findings e.g. for more meaningful info, people may use semantic coding for STM. This means the findings have limited application
   • Capacity = JACOBS and MILLER
     • developed a technique to measure digit span - the researcher gives 4 digits and the ppt is asked to recall them in the right order. If they get this correct, the researcher reads out 5 digits for them to remember and so on until they make a mistake
       • Jacobs found that the mean span for digits was 9.3 and for letters was 7.3
     • Miller looked into the span of memory and chunking - he saw that things come in 7s - musical notes, 7 deadly sins, 7 days of the week - therefore he concluded that the span or capacity it 7+-2. He also noted that people can recall 5 words as well as 5 letters. This is done by chunking - grouping letters or units into chunks.
     • Lacking validity = conducted a long time ago (1887) so lacks adequate control - ppt's may have been distracted whilst being tested. Therefore confounding variables may have been there which were not controlled. However, the results have been confirmed in other research - supporting it's validity
     • Not so many chunks = limitation - other researchers found that the capacity of STM was only about 4 chunks - this suggests that the lower end of Miller's estimate (5) was more accurate
   • Duration of STM = PETERSON AND PETERSON
     • tested 24 undergraduate students - each took part in 8 trials. On each trial the student was given a consonant syllable and a three digit number. The student was asked to count down from this number (preventing rehearsal for the syllable). On each trial they were asked to stop after different amounts of time e.g. after 3,6,9,12,15,18, seconds - this was called the retention interval.
     • Duration of LTM = BAHRRICK
       • Studied 392 ppt's from Ohio state aged between 17-74. Highschool yearbooks were obtained. Recall was tested in various ways e.g. photo recognition and a free recall test where ppt's recalled the names of their graduating class.
       • Ppt's who were tested within 15 years of graduation were about 90% accurate in the photo recognition. After 48 years, recall declined to around 70% for photo recognition. Free recall wasn't as good as recognition. It went from 60% at 15 years to 30% after 48 years. This shows that LTM can't last long.
       • Higher external validity = studied a real life situation. The downside is that confounding variables are not controlled e.g the ppt's may have looked at their yearbook photos and rehearsed the memories over the years.
     • Results suggested that STM had very short duration, unless we repeat something over and over again (verbal rehearsal)
     • Meaningless stimuli = remembering consonant syllables doesn't resemble an everday situation. Lacks external validity. However we do remember fairly pointless things like phone numbers so the study wasn't completely irrelevant.

2. The Multi-store memory model

   • Stimilus from environment
   • Sensory register (iconic or echoic)
   • Short term memory store
     • Maintenance rehearsal is rehearsing things to pass them to LTM
   • Long term memory store
   • <- <- <- Retireval
   • -> -> -> Rehearsal
   • Sensory register = a stimulus from the environment will pass on to the sensory register - two main types iconic and echoic. Iconic information is coded visually. Echoic information is coded is coded by sound.
     • Material in the sensory register doesn't last long - about less than a second - however it has a very high capacity. Very little of what enters the sensory register actually goes further into the memory system but if we pay attention it does. Attention is the key process
   • Short term memory = a limited capacity store, can only contain a certain amount before forgetting (between 5-9 items - 7+-2). Information in STM is coded acoustically and lasts about 30 seconds unless it is rehearsed. Maintenance rehearsal occurs when we repeat material over again. If we rehearse enough, it passes into LTM
   • Long term memory = potentially permanent memory store. Bahrick's study shows how much we can remember. LTM's are coded semantically. To recall it, we have to retireve it back to STM (retrieval
   • Supporting research evidence = research showing STM and LTM are different - Baddeley showed that we get words with similar sounds mixed up in STM. We mix up words with similar meanings in LTM. The strength of this study is that we can see that we code acoustically for STM and semantically for LTM. So they are different and so this supports the MSM's view that STM and LTM are separate
   • There is more than one type of STM = people suffering from amnesia show that only having one type of STM isn't true. A patient was studied known as KF. They found that KF's STM for digits was poor when they read them out to him. However when he read them himself, his recall was much better. The unitary STM is a limitation if the MSM because research shows that a the very least there mustbe one short-term store to process visual information and another one to process auditory information.
   • There is more than one type of rehearsal = some psychologists found the prediction of the more you rehearse something, the more likely you are to remember is actually wrong. They found there are two types of rehearsal. Maintenance rehearsal which only keeps info in the STM and elaborative rehearsal which is needed for LTM storage. This is major limiatation because it is yet another finding that can't be explained by the MSM model

3. Types of long term memory = TULVING

   • EPISODIC MEMORY = the ability to recall events (episodes) from our lives. e.g. the most recent visit you had to the cinema or a concert you went to or what you had for breakfast etc. The memories are time stamped (remember when they happen) The memory of an episode will include several elements e.g. people, place, objects, behaviours - all of these produce one memory. You make a conscious effort to recall episodic memory - although you may able to really quickly
   • SEMANTIC MEMORY = this store contains knowledge of the world e.g. how to apply for a uni or what the taste of an orange is like. Mix between an encyclopedia and a dictionary. These memories are not time stamped so we don't remember when we learn them. The knowledge is less personal. However it is a lot more than just facts - immense collection of material that is constantly being added to
   • PROCEDURAL MEMORY = our memory for actions, skills, how we do things. We can recall these memories without conscious awareness or a great deal of effort. e.g. driving a car. Our ability to drive a car depends on procedural memory. We change gear without having to recall how. They are skills we might even find hard to explain to someone else. If you are trying to describe what you are doing whilst driving the car, the task may become more difficult.
   • Clinical evidence = famous case studiesnof HM and Clive Wearing are relevant. Episodic memory in both men was impaired as a consequence of amnesia. They had great difficulty recalling events. However, their semantic memory was unaffected e.g. they still understood the meanings of words. He couldn't remember stroking a dog half an hour before or owning a dog in the past but he still understood the concept of a dog. Their procedural memories were still in tact. Clive Wearing was a musician and could still remember how to read music and play piano.Supports that fact there are three different LTM stores.
   • Neuroimaging evidence = evidence from brain scans - a psychologist got ppt's to complete various memory tasks whilst having a PET scan. They found that episodic and semantic memories were both recalled from the prefrontal cortex. Epsiodic = right prefrontal cortex. Semantic = left prefrontal cortex. This is a strength because it shows physical reality to the different types of LTM - supports the validity
   • Real life applications = a psychologist demonstrated that episodic memories could be improved in old people who had mild cognitive impairment. The trained ppt's performed better on a test of episodic memory after training than a control group. Episodic memory is most commonly affected by cognitive impairments, which highlights the benefits of being able to distinguish between types of LTM - appropriate treatments can be established

4. The working memory model

   • Central executive = attentional process that monitors incoming data, makes decisions and allocates systems to tasks
   • Phonological loop = deals with the auditory information. Subdivided into two - the phonological store = stores the words you hear. The articulatory process = allows maintenance rehearsal. The capacity of this loop is believed to be two seconds worth of what you can say.
   • Visuo-spacial sketchpad = stores visual/spacial information eg. if you are asked how many windows are in your house you visualise it - the capacity of this is thought to be 3 or 4 objects. Divided into two - the visual cache = stores visual data. The inner scribe = records the arrangement of objects
   • Episodic buffer = was added recently by Baddeley - it is a temporary store for information, integrating the visual, spatial and verbal information processed by other stores and maintaining a sense of time sequencing - basically recording events that are happening
   • Clinical evidence = Support from the WMM comes from a case study on KF. - He suffered from brain damage. He had poor STM ability for verbal information but could process visual information normally. This suggested that his phonological loop had been damaged leaving other areas of memory in tact. This supports the existance of a separate visual and acoustic store. However, evidence may not be reliable because each person is unique.
   • Dual task performance = studies of dual task performance support the separate existance of the visuo-spatial sketchpad. Baddeley found that ppt's had more difficulty doing two visual tasks than both a visual and verbal task at the same time. This increased difficulty because doing both visual tasks mean that you are competing for the same slave system but by using visual and verbal slave systems, there is no competitiveness. This means there must be separate systems that process visual information.
   • Lack of clarity over the central executive = some psychologists suggest that this component doesn't explain anything. Baddeley said 'It's the most important but least understood' - it needs to be more clearly specified. This means the WMM hasn't been explained.

5. Explanations for forgetting = interference

6. Explanations for forgetting = retrieval failure

7. Eyewitness testimony = misleading information

8. Eyewitness testimony = Anxiety

9. Improving eyewitness testimony = cognitive interview

Imágenes y archivos del mapa