Y1 Module 2 - Memory Flashcards
Outline the meaning of short term memory (STM).
STM is the capacity of the brain to hold a small amount of information for a short period of time. STM is the limited-capacity memory store (5 - 9 items on average). The duration of STM is about 18 - 30 seconds. Encoding of information is primarily acoustic.
Outline the meaning of long term memory (LTM).
The permanent memory store. The capacity of long term memory could be unlimited. Duration can be anything from a few minutes to a lifetime. Encoding of information is primarily semantic (meaning).
Describe the meaning of capacity.
The amount of information that can be stored in memory at any one time. Miller (1956) found STM has a capacity of 7 +/-2 items. LTM capacity is potentially unlimited.
Describe the meaning of duration.
The length of time information can be held in memory. Peterson and Peterson (1959) found STM has a duration for roughly 30 seconds. Bahrick (1975) found LTM has a potentially unlimited duration.
Describe the meaning of coding.
The format in which information is stored in various memory stores. STM is normally coded acoustically and LTM is normally coded semantically.
Outline Jacobs’ (1887) research on capacity.
Jacobs (1887) measured digit span.
Participants were given a sequence of digits and then asked to recall them out loud in the correct order.
The sequence was increased by one each time until the participant could no longer recall the sequence.
The mean span was 9.3 for numbers and 7.3 for letters.
Evaluate Jacobs’ (1887) research on capacity.
One strength of Jacobs’ study is that it has been replicated.
An old study is very old and is likely to have been poorly controlled.
Participants may have been distracted and performed worse.
This may reduce the validity of the research due to poorly controlled confounding variables, e.g. the longer the digit sequence the more time there is to get distracted.
The results of this study have been supported by further research supporting its validity.
Evaluate Miller’s (1956) research on capacity.
Miller (1957) suggested that the number of items that could be held in short term memory was 7 (plus or minus 2). Miller based his ideas on the prevalence of seven in human evolution (7 days of the week, seven deadly sins etc).
Miller also noted that people can recall 5 words as well as 5 letters. This is because people can chunk information into one item.
Miller may have overestimated the capacity of STM.
Cowan (2001) reviewed other research and concluded that the capacity of STM was only 4 chunks. This suggests Miller’s lower estimate of 5 is more appropriate.
Evaluate research on the duration of STM.
Meaningless stimuli. The material used was artificial - nonsense trigrams do not represent real life.
Lack of external validity.
Forgetting can be explained by: spontaneous decay - if the information is not rehearsed the memory trace simply disappears, or displacement - new information pushes old information out due to the limited capacity of STM.
Evaluate research on the duration of LTM.
Bahrick et al (1975) studied 392 participants from age 14 - 74.
Participants were asked to recall ex-school friends via: a photo recognition test of 50 pictures; a free recall test where they recalled the names of all people from their graduate class.
Photo recognition was 90% accurate after 15 years and 70% accurate after 48 years and free recall was 60% accurate after 15 years and 30% accurate after 48 years.
Real life memories were studied which gives this study a high external validity.
Studies with meaningless information such as Shepard (1967) have much lower recall rates.
It is hard to control confounding variables in this study, e.g. participants are likely to have looked at yearbook photos and rehearsed their memory over the years.
Evaluate research on coding.
Baddeley (1966a, 1966b) gave different word lists to four different groups. The word lists were: acoustically similar, acoustically dissimilar, semantically similar, semantically dissimilar. Participants had to recall the words immediately and after a period of time.
Participants did worse immediately with acoustically similar words.
Participants did worse after 20 minutes with semantically similar words.
The study suggests we encode STM acoustically and LTM semantically.
This study has been criticised for using artificial stimuli. This suggests it lacks external validity and so the findings cannot be generalised, e.g. it is highly likely meaningful material is encoded semantically in STM.
What are the key features of the multi-store model of memory (MSM)?
Atkinson and Shiffrin (1968, 1971) (who created it) suggest memory is made up of three stores linked together by processing.
Environmental stimuli»_space;> sensory register (iconic, echoic, other sensory stores)»_space;> attention»_space;> STM»_space;> either response or prolonged rehearsal (which can go back to STM by maintenance rehearsal)»_space;> LTM (can go back to STM by retrieval)
Outline the sensory register aspect of the MSM.
A stimulus from the environment passes into the sensory register along with lots of other sensory information (sights, sounds, smells). There are five stores in the SR. One for each sense: auditory (echoic memory), visual (iconic memory), touch (tactile memory), smell (olfactory memory), taste (gustatory memory).
Duration is very brief (less than one second). Capacity is high. Coding depends on the sense. Little information from the SR passes further into memory. You have to pay attention for the information to pass to STM.
How is information transferred from STM to LTM?
Maintenance rehearsal (repeating the information to yourself) keeps the information in STM. If the information is rehearsed for long enough it passes into LTM - prolonged rehearsal.
How are memories recalled in the MSM?
Information has to be transferred back to STM by a process called retrieval.
Give one strength and one limitation of the MSM. (KF study)
The MSM is supported by research showing STM and LTM are different. Baddely (1966) found that we tend to mix up words that sound similar when using our STMs but we tend to mix up words with similar meanings when using LTM. This clearly shows that coding in STM is acoustic and LTM is semantic. This supports the MSM’s view that these two memory stores are separate and independent.
A limitation is that evidence suggests there is more than one type of STM. Shallice and Warrington (1970) studied KF, a patient with amnesia. KF’s STM for digits was poor when read out loud to him. His recall was much better when he read the digits himself. The MSM suggests there is only one type of STM but the KF study suggests there must be one short term store to process visual information and another to process auditory information. The working memory model is a better explanation for this finding because it includes separate stores.
Give two limitations to the MSM. (other than KF study)
Another limitation of the MSM is that it only explains one type of rehearsal. Craik and Watkins (1973) argued there are two types of rehearsal - maintenance and elaborative. Maintenance is the one described in the MSM. But elaborative rehearsal is needed for long-term storage (linking information to your existing knowledge). This is a very serious limitation of the MSM as it is another research finding that cannot be explained by the model.
Another limitation is that research studies supporting the MSM use artificial materials. Researchers often asked participants to recall digits, letters. e.g. Peterson and Peterson asked participants to record syllables. These have no meaning/usefulness. In everyday life we form memories related to useful things and meaning - people’s faces, facts, places, etc. This suggests that the MSM lacks external validity. Research findings with meaningless material may not reflect how memory works in real life.
Outline the episodic memory of the LTM store.
Stores events (likened to a diary of daily happenings).
Episodic memories are complex.
Events are time-stamped (you remember when they happened).
They involve several elements (people, places, behaviours all in one memory).
You have to make a conscious effort to recall them.
Outline the semantic memory of the LTM store.
Stores our knowledge of the world (the meaning of words, taste of an orange, make of a car).
The memories are not time stamped.
You do not normally remember when you gained the knowledge.
The knowledge is less personal - more to do with knowledge that everyone can share.
Outline the procedural memory of LTM.
Stores memories for actions and skills.
Memories of how we do things (riding a bike, playing a sport).
Recall occurs without awareness or effort.
It is hard to explain these actions or skills as they are recalled without conscious awareness.
Give three strengths about research into the types of LTM.
A strength of episodic memory is that it is supported by case study evidence. Clinical studies of amnesia (HM and Clive Wearing) showed both had difficulty recalling events that had happened to them in the past. However, their semantic memories were relatively unaffected (e.g. HM would not recall stroking a dog 30 mins previously but he knew the concept of a dog). This supports the view that there are different memory stores in the LTM as one store can be damaged but the others remain unaffected.
A strength is that brains scan studies show that there are different LTM stores. Tulving et al. (1994) had participants perform various memory tasks while their brains were scanned with a PET scanner. Episodic and semantic memories were in the prefrontal cortex; semantic in the left and episodic in the right hand side. This shows a physical reality in the brain to different types of LTM which has been confirmed in many research studies, supporting its validity.
A strength is that identifying different LTM stores has real-life applications. Psychologists can target certain kinds of memory in order to improve people’s lives. Belleville et al. (2006) found that episodic memories can be improved in older people with mild cognitive impairments. Training to improvements compared to the control group. This highlights the benefit of distinguishing between different types of LTM - it allows specific treatments to be developed.
Give two limitations about research into the types of LTM.
A limitation of Tulving’s approach is that there may be only two types of LTM. Cohen and Squire (1980) argued that episodic and semantic memories are stored together in one LTM store called declarative memory (memories that can be consciously recalled). Cohen and Squire agree that procedural memory is a distinctly different kind of memory to semantic/episodic, and called it non-declarative. It is important to get the distinction between semantic and episodic memories right because the way we define them influences how memory studies are conducted.
A limitation is that there are problems with clinical evidence. Evidence is often based on clinical cases (e.g. HM and Clive Wearing) about what happens when memory is damaged. There is a serious lack of control of different variables in these studies. So it is difficult to generalise from these case studies to determine the exact nature of LTM.
Outline the key features of the working memory model (Baddeley and Hitch 1674).
It is an explanation of how STM is organised and how it functions. It is concerned with the part of the mind that is active when you are thinking.
Central executive, episodic buffer, visuospatial sketch pad, phonological loop (articulacy control system and phonological store).
Outline the key features of the central executive (CE).
Monitors incoming data. Allocates slave systems to tasks. Has a very limited storage capacity. Coding is flexible.
Outline the key features of the phonological loop (PL).
Deals with auditory information. Preserves the order in which the information arrives. The phonological store stores the words you hear. The articulatory process allows maintenance rehearsal. Capacity is about 2 seconds worth of what you can say. Coding is acoustic.