Research on coding
Information is stored in memory in different forms depending on the memory store. This convention of info is called coding. Baddeley gave different lists of words to four groups of participants. Acoustically similar, acoustically dissimilar, semantically similar and semantically dissimilar. STM acoustically similar words were worse and LTM did worse with semantically similar words suggesting STM is coded acoustically and LTM semantically
Research on capacity
Digit span - how much info can STM hold. Jacob’s (1887) Researcher would read out digits gradually increasing the amount until the participant gets it wrong showing the individuals digit span. Mean span for digits was 9.3 And for letters it was 7.3
Span of memory and chunking
Miller (1956) made observations of everyday practice. He notes that things come in 7s. Therefore he thought that the STM capacity was 7 +- 2. He also noted that people can recall five letters like digits by chucking. Grouping letters or digits into chucks
Research on duration of STM
How short is STM? Peterson (1959) tested 24 students in 8 trials each. They were given a consonant syllable to remember as well as a 3 digit number. They counted back from the number until told to stop. They were told to stop after various times (3*) after 3 the recall was 80% and after 18 it was about 3% suggesting STM lasts 18 seconds unless repeated over and over
Research on duration of LTM
Bahrick et al (1975) studied 392 Americans aged 17-74. Highschool yr books were obtained and recall was tested in many ways. Photo-recognition and free recall test where participants recalled names from their grad class. Participants tested within 15 years were 90% on photo and 60 on recall while after 48 it dropped to 70% and 30%
Evaluation of coding research
+ Baddeleys study clear identified 2 stores. And was an important step in understanding the Multi- store model
- the study use artificial stimuli rather than meaningful material so may have limited application
Evaluation of capacity
+ jacobs study has been replicated meaning it has high reliability
- Millers research may have overestimated STM capacity and it may only have 4-+ chunks
Evaluation of LTM AND STM duration
- Peterson study had an artificial situmlus with no meaning. Lacks external validity
+ LTM has high external validity because the stimulus was meaningful. This creates a more real estimate on duration
The multi-store model
Atkinson and Shiffrin’s multi-store model suggest memory is made up of 3 stores linked by processing
The multi-store model sensory register
All stimuli from the environment pass into the sensory register. This part comprises several registers one for each sense. Coding in each is modality-specific. For example the store for visual in iconic and the store for audio is echoing. Very brief duration and only passes further if you pass attention to it
The multi-store model short term memory
Info in the short term memory is coded mainly acoustically and last about 18 secs unless rehearse so STM is a more temp store. It’s also of limited capacity of between 5-9 things. If rehearsed enough it passes to the LTM
The multi-store model LTM
This is the potentially permanent store for memory that has been rehearsed. Coded semantically (terms of meaning) and its duration may be life long. According the the MSM we recall info from LTM by retrieval
Evaluation of The multi store model of memory
+ Support from studies showing difference in STM AND LTM
- evidence of more than one STM store Warrington studied a client KF who had a memory disorder but could better recall what he had read suggesting there could be another STM for nonverbal sounds
Types of LTM
Tulving (1985) recognised the MSM as to simplistic and proposed 3 types of LTM
Episodic
Semantic
Procedural
Episodic memory
Refers to our ability to recall events and has been likened to a diary and a record of daily experience. They are all timestamped and will include several elements such as people and places and you have to make a conscious effort to recall them
Semantic memory
Contains our knowledge of the world and has been liked to a combination of an encyclopaedia and a dictionary. Includes knowledge such as what things taste like and meanings of words and knowledge of concepts. These are not timestamped and is less personal. It’s ever growing and less velnerable to distortion
Procedural memory
Actions or skill. Essentially how we do things. We recall this unconsciously and without much effort. And example of this is playing an instrument. These are the skill that are hard to explain to another person
Evaluation of the types of LTM
+ case study of wearing - episodic memory was damaged in an accident but the semantic memory was fine as well as procedural
— conflicting research linking types of LTM to areas of the brain
+ real world application - allows physiologists to help people with memory problems by bellevilles creating an invention to help episodic memory in old people
The working memory model
The working memory model is an explanation on how STM is organised. The WMM is concerned with mental space that is active when we are temporarily storing and manipulating info eg when playing chess. This consists of 4 main components
The working memory model central executive
The central executive has a supervisory role and monitors incoming data and focuses and devises out limited attention and allocates slave systems to tasks. Has limited processing capacity and doesn’t store info
The working memory model phonological loop
On slave system is the phonological loop and deals with all auditory information and the coding is acoustic. It preserves the audio in the order it arrives and is subdivided into
- the phonological store which stores the words you hear
- the articulatory process which allows maintained rehearsal. The capacity of this loop is believed to be 2 secs of what you can say
The working memory model Visuo-spatial sketch pad
The 2nd slave system is the VSS and it stores physical and spatial info when required. Eg if asked how many window on a house you’d visualise it. It has a limited capacity of about 3-4 objects and can be divided into the visual cache (visual data) and inner scribe (recoded the arrangement of objects in visual field)
The working memory model episodic buffer
The third slave system in the EB. It is a temp store for info integrating the visual, spatial and verbal information processed by other stores and maintains a sense of time sequencing. It’s the limited (4 chunks) storage box of the CE and links the WMM to LTM
Evaluation of the working memory model
+ support from Warrington case study of patient KF. He had poor STM for auditory info but could process visuals strongly implying the existence of 2 separate parts
- One limitation is that there is a lack of clarity over the nature of the CE
