Memory Flashcards
Memory definition.
The mental processes involved in retaining information.
Three aspects of the memory process.
Encoding (creating a memory trace).
Storage (holding the information in the memory).
Retrieval (accessing the stored information).
Short term memory duration.
Brief duration 18-30 seconds, it is a temporary store and anything that we need to remember for a longer period of time needs to be transferred into the LTM.
Test for duration of STM.
Peterson and Peterson (Brown Peterson).
Participants briefly shown a consonant trigram and asked to count back in threes, preventing them from rehearsing the letters. After intervals of 6,9,12,15,18 participants were asked to recall the original trigram WITHIN 30 SECONDS
Results of Peterson and Peterson.
Participants were able to recall 80% of trigrams after a 3 second interval.
Progressively fewer trigrams were recalled as the time intervals lengthened.
After 18 seconds, fewer than 10% of the original trigrams were recalled correctly.
Strengths of the Peterson and Peterson technique.
Controlled lab experiment, allows control over extraneous variables (other distractions), increasing validity of the experiment and it is easily replicable.
Limitations of the Peterson and Peterson technique.
Controlled lab experiment, artificial and not relevant to the real world, decreasing external validity.
Duration of long term memory.
Lifetime.
Test for duration of LTM.
Yearbook Study - Bahrick.
Used 392 people who had graduated over a 50 year period. Participants were split into 2 groups (independent measures). Recognition group and recall group.
The recognition group were asked to state whether they recognised the faces of of people from school or not, the recall group were asked to name the people.
Results of the Yearbook Study.
Recognition group - 15 years since graduations - 90% accurate at identifying people. 48 years since graduation - 70% accurate.
Recall group - 15 years since graduation - 60% accurate. 48 years since graduation - 30% accurate.
Strengths of Bahrick’s research.
High external validity, investigated meaningful memories (names and faces).
It is supported by other research, recently (2008) Bahrick researches whether people could remember their grades at college or not, 3025/3967 college grades were correctly remembered, showing that the original research has high reliability and accuracy.
Limitations of Bahrick’s research.
Possible extraneous variables (some people could still be in contact with the people from their class), lacking internal validity.
Test for capacity of short term memory.
Digit span technique - Jacobs.
Presented with a sequence of numbers and IMMEDIATELY recalling them in the order that they appeared. This continues until a mistake is made, showing that the STM has reached its capacity.
443 female students were studied using letters and numbers, it was found that numbers were recalled better than letters. On average people could recall between 5 and 9 items.
Miller conducted meta analysis on digit span technique and came to the same conclusion - the ‘magic number’ is 7+-2.
Chunks - Combinations of individual letters or numbers into a meaningful unit (MRI, GCSE, 999).
This allows us to store more in the STM as chunks only take up one space, leaving 6 more to fill.
Strengths of research into capacity of STM.
Findings have been the same in replicated experiments with better controlled conditions (lack of distractions), high validity.
Higher external validity using numbers as we are more likely to be asked to remember a series of numbers (phone numbers).
Limitations of research into capacity of STM.
Miller may have overestimated the capacity of STM, Cowan concluded that the capacity of the STM is only 4 +-1 chunks, lack of reliability, Miller’s original research lacks internal validity.
Jacobs’ and Miller’s research into STM does not take other factors into account, capacity decreasing as age increases, extraneous variables are ignored.
Miller’s research did not specify how large each chunk could be, lacks specific important information.
Coding of STM and LTM.
Storing information can be done visually according to how it looks, acoustically according to how it sounds, or semantically according to its meaning.
Study for coding for STM and LTM.
Baddeley (1966) - substitution error study.
People asked to remember letters or words and the mistakes were focussed on. Confusing things that look the same suggests the participant was encoding the material visually.
Confusing things that sound the same suggests that they were encoding the material acoustically.
Confusing things that have the same meaning suggests that the participant was encoding the material semantically.
Participants put into 4 groups (independent measures), each with a different set of words.
Group 1 - acoustically similar, group 2 - acoustically dissimilar, group 3 - semantically similar, group 4 - semantically dissimilar.
Results from the substitution error study.
When recalling from STM (immediately after) participants did worse recalling words that were acoustically similar.
When recalling from LTM (20 mins after) participants did worse with the words that were semantically similar.
This shows that STM uses acoustic coding and LTM uses semantic coding.
Strengths of research for coding.
Baddeley’s study identified a clear difference between 2 memory stores, shows that there is definitely a difference between LTM coding and STM coding, making the research more accurate.
Conrad gave participants letters to recall, some were acoustically similar and others were acoustically dissimilar, more mistakes were make with letters that sounded the same, this is further evidence that acoustic coding is linked with STM, increasing accuracy.
Limitations of research for coding.
Baddeley’s study used quite artificial stimuli, using word lists rather than meaningful material, decreasing external validity because it is not relevant to everyday life.
Does not account for different types of LTM - episodic, procedural.
Posner found evidence to suggest that visual codes are used in STM, this contrasts with the work of Baddeley and Conrad, whose research implied that STM uses acoustic coding, this reduces the validity as results are not consistent.
The multi-store model.
The sensory information comes in from the environment (5 senses).
The information travels to the sensory register store, the duration is 0.5 seconds, the capacity is large, the information is coded in sub-stores for each type of sensory information (iconic sub-store - visual, echoic sub-store - auditory). Information is lost from here due to it being filtered out after not paying attention to it (95-99% of info is filtered out).
If information is payed attention to it moves to the short-term memory, the duration is 18-30 seconds without rehearsal (Peterson trigram study shows this), the capacity is 5-9 items (the digit span technique shows this), this information is coded mainly acoustically (shown by the substitution error study). Information is lost due to lack of availability, exceeding the duration or capacity (decaying and displacement). The maintenance rehearsal loop increases the duration of the STM.
Information if moved into the long-term memory through prolonged rehearsal which requires a lot of effort. The duration can be up to a lifetime (shown by the yearbook study - Bahrick), the capacity is unlimited, the information is coded mainly semantically (shown by the substitution error study). Information is lost from the LTM due to a lack of accessibility, retrieval failure (lack of cues or interference). Info can be moved back into the STM through retrival.
Strengths of the MSM.
Supporting case study, Clive Wearing, anterograde amnesia, cannot move new info from STM to LTM. Suggests that the STM and LTM are 2 separate memory stores which is what the MSM suggests.
Free recall experiments show that the first and last words in a series are remembered, predicted by the MSM.
Limitation of the MSM.
Too simplistic, STM is more complicated than the MSM says.
Over-emphasised the idea of prolonged rehearsal, Tulving; participants asked to read list of words over and over again, did not find that this rehearsal meant that words were recalled more frequently or easily.
Tulving argument.
MSM is too simplistic for explaining LTM, said there was 3 sub-stores, episodic (events), semantic (knowledge), procedural (skills).
Episodic memories.
Memories of events. Time stamped. Include people, places, objects and behaviours. Requires effort to recall.
Semantic memory.
Knowledge. Less personal. Constantly being added to. Less vulnerable to distortion or forgetting.
Procedural memory.
Skills. Recall without conscious effort. Difficult to describe to someone else.
Strength of Tulving’s theory.
Supporting case studies, Clive Wearing, no longer create new episodic or semantic memories, procedural skills relatively unaffected.
Practical applications to help people with memory problems, specific to episodic memory, strategies to help.