memory

• How did Baddely research coding


  he found there was immediate worse recall for acoustically similar words so STM is coded mainly acoustically and he found recall after 20 minutes was worse with semantically similar words so LTM is coded mainly semantically
• how is short term capacity measured


  Jacobs did the digit span test where the researcher reads four digits and increases the number of digits until the participant cannot recall the order correctly and on average participants could repeat back 9.3 numbers and 7.3 letters
• How did Miller come up with the magic number


  Miller observed everyday practice and noted that things come in sevens for example days of the weeks, notes of musical scale. The span of the stem is about 7 items plus or minus 2 but is increased by chunking where groups of dogs are out into sets if meaningful things
• How was the duration of STM found out

  Peterson and Peterson gave 24 students consonant syllable to recall and a 3 digit number to count backwards from after a retention interval of 3,6,9,12,15 or 18 seconds. After 3 seconds average average recall was about 80% and after 18 seconds it was 3%. STM duration without rehearsal is up to 18 seconds
• How was the duration of LTM found out

  Bahrick conducted a study using year book photos and participant were aged between 17 and 74 they did :

  recognition test: 50 photos from high school yearbooks

  free recall test: participants listed names of their graduating class

  They found that for recognition test was 90% accurate after 15 years and 70% after 48 years. And for free recall 60% after 15 years and 30% after 48 years
• Strength of Baddelys study


  One strength of Baddelys study is that he identified two memory stores. Later research showed that there are no exceptions to his findings but STM is mainly acoustic and LTM is mainly semantic which led to the development of the multi store model
• one limitation of Baddeleys study


  Baddeley used artificial stimuli as the words used had no artificial meaning to the participants sp tells us little about coding for everyday memory tasks when processing more meaningful information people use semantic coding even for STM, this means the findings of the study have limited application
• a strength of Jacobs study

  A strength is that it has been replicated. In Jacobs study there may have been confounding variables such a noise which could've caused distraction while when this study was repeated in a more controlled environment the results were confirmed and therefore Jacobs study is a valid measure.
• a limitation of Millers study


  A limitation is that it may have overestimated the STM capacity when Cowen reviewed other research he found that the capacity was only about 4 plus minus 1 chunks
• a limitation of Peterson and Peterson study 


  One limitation of the study is the meaningless stimuli. It is not completely irrelevant as sometime we need to recall meaningless things but in reality the recall of consonants is not reflecting the complexity of real life
• strength of Bahricks study

  Has high external validity as reflects everyones meaningful memories such as people faces and names, when lab studies were conducted with meaningless pictures recall rates were lower and this means that Bahricks et al findings are a more 'real' estimate of duration of LTM
• Multi store model 


  Describes how information flows through the memory system
• sensory register


  all stimuli from the environment and passes to the sensory register
• coding of sensory register

  modality based
• capacity of sensory register


  very large
• duration of sensory register

  0.5 seconds
• how does information pass from SR to STM

  Attention
• STM

  a limited capacity store of information for a temporary duration
• coding of short term memory

  mainly acoustically
• capacity of short term memory

  7 -/+ 2 items
• duration of short term memory

  18 seconds
• how does information get to long term memory

  maintenance rehearsal occurs when we repeat material to ourselves
• long term memory


  permanent store of information
• capacity of long term memory


  potentially unlimited
• coding of long term memory

  mainly semantic
• duration of long term memory

  indefinite
• strength of MSM

  A strength is research support showing STM and LTM are different. Baddeley found that we tend to mix up words that are acoustically similar when using our STM and we mix up semantically similar words in our LTM and this supports the idea of their separate stores
• first limitation of MSM

  1.A limitation is evidence suggesting there is more than one STM store as a case of KF where STM recall for digits was poor when he heard them but much better when he read them and therefore there may be different units within the STM and the MSM itself is too simplistic.
• second limitation of MSM

  2.Another limitation is prolonged rehearsal is not needed for STM-LTM transfer as psychologists researcher there are two types if rehersal one maintenance and one elaborative and elaborative is needed for long term memory storage which links information with existing knowledge and its meaning and MSM doesn't suggests of LTM storage is made
• Episodic memories


  stores events from our lives which are linked to a diary of daily experiences such as a trip to paris

  they are time stamped so you remember when they happened and relate in time

  you make a conscious efforts to recall them
• semantic memories


  semantic memories are stores of knowledge of the world such as capital cities these are not time stamped but are consciously recalled
• procedural memories 


  stores memories of actions and skills, these are memories of how we do things for example riding a bike these skills become automatic with practice and are not consciously recalled
• strength of LTM

  one strength is case study of HM and CW who showed both difficulty recalling events that happened to them in their pasts but their semantic memories were in tact and procedural and hence supports the idea of separate stores

  another strength is people with memory problems found it harder to recall episodic memories that were recent but their past episodic memories were still in tact and this meant that intervention could be put in place to improve their memory compared to a control group and this shows that there's real world application
• three stages of information processing in multi store model


  1.sensory information is perceived

  2.the sensory information is transferred to the STM where it is maintained by rehearsal

  3.the information is transferred to LTM
• First strength of multi store model

  -the short duration of SR is supported by evolutionary theory as in the wild quick reactions are vital for survival and only important information would b retained and processed as too much information would lead to slower reactions
• Second strength of multi store model


  There's a large base of research that supports the idea of distinct STM and LTM systems in the case of Sallice and Warrington study of KF a brain damaged patient whose STM was impaired following a motorcycle accident but his LTM was still intact.
• First limitation of multi store model

  Some research into the STM has low mundane realism as the stimuli used by Peterson and Peterson used nonsense trigrams which do not reflect the complexity and meaningfulness of real life information and lack of ecological validity as carried out in a lab may lead to demand characteristics which can lead to low external validity of the findings.
• Second limitation of multi store model

  The model may be too simplistic as suggests STM and LTM are unitary stores. Research shows that the STM is divided in sub slave units and LTM has different types and the model doesn't suggest this.
• Limitations of LTM


  -Using case studies like CW and HM allows us to gain insight that's not otherwise possible but lack of generalisation as these studies are different to the normal population in some way even before the demage. It is difficult to make conclusions of a damaged brain to the rest of the population
• central executive


  Gives direct attention to particular tasks determining how the brain's resources are allocated to tasks

  Central executive has limited capacity