Processes involved in memory
ENCODING: Transferring information from a sensory form into a form which can be processed. Encoding can be either:
- Visual - process the physical appearance of things
- Acoustic - process sound information
- Semantic - process the meaning of things
STORAGE: Hold information in memory
RETRIEVAL: The process of locating information in memory and extracting it. Two types of retrieval:
- Recall - find information and extract it ourselves
- Recognition - identify familiar information
MEMORY - a store for mental representations of events, images, ideas and information after the original stimuli are no longer present
Encoding is necessary for storage to occur (we cannot remember something if we did not make sense of it or notice it in the first place) however encoding is not sufficient for storage to occur (just because we made sense of something it doesn't mean that it will be stored in memory).
Storage is neccessary for retrieval to occur (we cannot remember something if we have never stored it in the first place), however, it is not sufficient for retrieval to occur (just because something is being stored it is no guarantee that it will be remembered on any given occasion)
Glanzer & Cunitz
- Investigated people's memory of 20 words in a list.
- They found that people recalled more words from the beginning of a list (the primacy effect) and the end of a list (the recency effect) than the words in the middle
- They called the curve that the results made 'The serial position curve'.
- Their findings provide support for the multistore model of memory because...... we tend to remember the first words on the list very well, which suggests that we have had time to rehearse them and they become long-term memory (primacy effect). We remember the final words on the list well because we learnt them more recently and so they are still in short-term memory (recency effect).
Atkinson & Schriffrin - Multi-Store Model
MSM Characteristics - Encoding
Definition: Form in which information is stored (Visual, Acoustic, Semantic)
SENSORY STORE: Sense specific, information from each sense has its own store. The two most commonly researched are: Iconic = Visual information. Acoustic = Sound information
STM = Conrad - Found that a list of letters that sound the same is harder to recall than a list of words that sound different to each other, suggesting that in STM, encoding is acoustic
LTM = Baddeley - Found it is mainly semantic but with some visual/acoustic encoding. Words with different meanings were easier to remember after 20 minutes than words with similar meanings. Suggests you must have encoded the meaning and they interfere with eachother.
MSM Characteristics - Capacity
Definition: How much information the store can hold
SENSORY STORE - Hard to investigate but potentially very large capacity as all sensory information is initially stored here.
STM = Miller - Refers to 'magic number 7' meaning we can remember 7 +/- 2 chumks of information. Within each chunk, we can fit more information if we add meaning to it. Short term memory is still very limited.
LTM = Merkle - Measured an estimate of synapses in the human brain. Did a complex mathematical sum. Found that the human brain has 1000GB storage. It could potentially be unlimited.
MSM Characteristics - Duration
Definition - How long we can hold information for.
SENSORY STORE - Externally brief. Iconic= maximum 1 second. Acoustic= maximum 4 seconds.
STM = Peterson & Peterson - Showed participants meaningless trigrams and asked them to recall them after 3-18 seconds. After 3 seconds they had 80% recall (on average). After 18 seconds, only 10% accurately recalled (on average). Information decays very quickly and there is an approximate 30 seconds duration. If we rehearse it, it will remain for longer.
LTM = Bahrick et al - They tested participants recall and recognition of their first class mates. One of their findings after 48 years, on average, participants had 70% accuracy recognition. memory (long-term) can potentially last forever.
Strengths of MSM
- The MSM was the first and most influential model of memory. This means that it has inspired a great deal into memory which has improved our understanding.
- The distinction between the stores is supported by research which supports this distintion. LTM - Bahrick (explain findings). STM - Peterson & Peterson (explain findings)
- The MSM is also supported by a wide range of clinical studies on amnesic patients, for example, that which shows how patients with amnesia (Clive Wearing) are unable to store new information (loss of STM) but have perfectly functioning LTM.
- The model can also explain the serial positioning curve effect.
Weaknesses of MSM
- The MSM is simplistic. It is now known that there are actually a number of stores within LTM (procedural, declaritive and episodic). STM is not one simple store - we know this because it is possible for people to do two things at once (which should not be possible in a simple store with limited capacity). Recent models have attempted to include this - e.g. Working Memory Model
- It cannot explain why we forget thinngs we rehearse things we rehearse over and over again for example when you revise for exams but then forget them soon afterwards.
- It cannot explain why we can remember things we haven't rehearsed for example we remember faces fairly naturally without having to rehearse it
- MSM is based on lab experiments - these lack validity for two reasons. 1) The stimuli people try to remember can be artificial - Petersn and Peterson tested participants recall of trigrams, which are not real life. In reality, people's memories are affected by emotion etc. 2) They test explicit memory rather than implicit memory
Working Memory Model - Baddeley & Hitch (1)
- The Central Executive has overall control, including control of the 'slave systems'.
- It is the most important component of WMM.
- It directs where our attention goes
- It combines information within STM
- It brings information from LTM to STM
- It is in charge of complex tasks, such as planning problem solving and decision making
Working Memory Model - Baddeley & Hitch (2)
THE PHONOLOGICAL LOOP:
- Where acoustic information is processed and stored. It can hold as much verbal information as you can say in approximately 2 seconds.
- "Inner ear" - We store what we hear
- Preparing what we want to say (speech production)
- Verbal rehearsal takes place
Working Memory Model - Baddeley & Hitch (3)
THE VISUOSPACIAL SKETCHPAD:
- Where we store visual information - "inner eye"
- Where we create and manipulate visual immages
- There is a limit to how much can be held
Evaluation of WMM - Strengths
- There is research evidence to support the WMM. Baddeley & Hitch/Gathercole and Braddeley - Both support that memory is made up of different components. Baddeley - Phonological loop can only hold 2 seconds of information
- Evidence that STM is made up of several components from fMRI scans: Bunge et al found, using fMRI scans, that different parts of the brain are active when doing different tasks. This supports the idea that you use different components for verbal and visual information in memory.
- Evidence that STM is made up of several components from amnesics (case studies): KF had a digit span of 1. Better visual STM than auditory. Suggests damage to his phonological loop but has a better visuospacial sketchpad. This supports WMM because it shows that there must be different components in memory.
- Explains how we are able to complete two tasks at once (dual task) - Baddeley & Hitch
- WMM has more detail about STM than the MSM. It says that there are separate components, rather than it being a unitary store.
Evaluation of WMM - Weaknesses
- The concept of the central executive is very vague - we don't really understand how it works - and actually there may be more than one central executive component. Since the original model, another component called the episodic buffer is suggested to be needed - it is a back up store for CE and communicates between STM and LTM
- Berz model fails to account for musical memory because we are able to listen to instrumental music without impairing performance on other acoustic tasks. According to WMM, we shouldn't be able to do this as they both belong to the phonological loop.
- A problem of using case studies as support for the WMM is that you cannot generalise the findings of obne person to everybody else.
- Lab studies lack ecological validity because controlled settings and artificial tasks eg. saying 'the' while doing a task is not what happens in everyday life.
Eye Witness Testimony (1)
Definition: the evidence given in court or police investigations by someone who has witnessed a crime or an accident.
- Wells et al (1979) - 45% people who had just watched a woman steal a calculator right in front of them identified her correctly from a set of 6 photographs when asked a few minutes later.
- The Devlin Report stated that there were 850 criminal court cases where the only evidence of guilt was EWT. 74% of these led to conviction.
- Wells et al (1998) - Reported on 40 cases in the USA where people who were convicted on the basis of EWT have since been cleared because of DNA evidence. 5 were on Death Row.
Eye Witness Testimony (2)
- A schema is our existing knowledge we have about the world based on our experiences. A bit like a mental script which tells us what to expect in different situations. Eg. A schema of a bank robbery is a masked person with a weapon and a bag, asking for money in the bank.
- Bartlett's theory of RECONSTRUCTIVE MEMORY argues that memory is not just a 'video' of the past - it is much more of an active process. How we remember information is affected by our pre-existing knowledge, attitudes and expectations. specifically, when we have gaps in our memory, information from our schema is used to fill in these gaps.
How does anxiety affect EWT? (1)
3 RESEARCH STUDIES:
1) Christianson & Hubinette - in a survey of 110 people who had witnessed, between them, 22 bank robberies, those who had actually been threatened by robbers (therefore feeling high level of anxiety) showed more detailed and accurate recall than those who had merely been onlookers.
This suggests that..... as anxiety increases, accuracy of EWT increases.
This was real life so it has better ecological validity.
However, if they were directly threatened, their memory was better as they were closer to the robber.
How does anxiety affect EWT? (2)
2) Loftus & Burns - Participants were shown a crime on video. Some saw a less violent version of it and others saw an extremely violent version of it. Those who saw the violent version were much less accurate in recalling events leading up to the incident.
This suggests that..... as anxiety increases, accuracy decreases
However, it was on a video so it lacks eco-logical validity
How does anxiety affect EWT? (3)
3) Peters - Participants were people attending their local health clinic for an injection. They met a researcher and a nurse (who gave them the injection and therefore assumed to be the more anxiety-inducing person) for equal amounts of time. A week later, they were asked to identify the researcher and the nurse from a set of photos. Recognition of the researcher was much more accurate.
This suggests that...... as anxiety increases, accuracy of EWT decreases
To an extent, it has ecological validity - realistic setting.
It may lack internal validity and the recognition is unnatural - lacks eco-logical validity
The Weapon Effect
Independent Variable - whether the man is holding a pen or a knife
Dependent Variable - Whether the man can be correctly identified
Link to inaccurate EWT because....... increased anxiety means that there were poorer accuracy. The weapon makes you anxious, so attention isn't focused on the person holding it.
Link to Peters' findings? the participants' attention may have been drawn to the needle.
How does age affect EWT? (1)
Pozzulo & Lindsay - Using a meta-analysis of numerous studies, they reported that:
Children under 5 were less likely to correctly identify a culprit in a line-up.
Children up to 13 were more likely to say that someone was the culprit in a line-up, even if the culprit was not there.
Poole & Lindsay - A= To investigate the effect of post-event information on children's recall
P= Children aged 3-8 were in a science demonstration. The parents then read them a story which contained parts of the demonstration and some novel information. Children were asked questions and found that they had incorporated much of the new information from the story.
F= Older children were much better at identifying the source of the information (whether from story or demonstration) but younger children could not.
C= Children are very vulnerable to incorporating info of an incident into memories - less accurate
How does age affect EWT? (2)
Yarmey - Participants watched a staged event involving a knife. 80% of elderly participants failed to mention the attacker had a knife in his hand compared to 10% of younger adults.
Cohen & Faulkner - Found that elderly participants are more susceptible to the effects of misleading information than younger adults, therefore suggesting that elderly adults can also be unreliable eye witnesses.
Young adults are more accurate EWs - having to recall accurately eg. exams
Evaluation of Age (EWT)
- Use of lab experiments: More control over extraneous variables so there is better internal validity - any change in IV causes DV to change.
- Real life application for courts and police: Findings can lead to police taking greater care when questioning young children and older adults to make sure that they do not include any misleading information or post event information that would compromise the accuracy of their statements.
- Use of lab experiments - It lacks ecological validity because you cannot apply this to real life.
- Ethical issues involved with using children in research - a child is less likely to understand (consent/right to withdraw). Children are more vulnerable so protection from harm must be considered.
- Individual differences - Research assumes that all younger children and older adults are poorer eye witnesses than younger adults when in fact it varies from person to person
Design - Independent Groups
- There are no order effects as participants aren't repeating the experiment
- Less chance of attrition as participants are involved for a shorter time
- There may still be participant variables
- You need more participants overall as it is more time consuming for participants and it is more costly for you.
HOW TO OVERCOME WEAKNESSES:
Use a matched pairs design. However, to overcome participant variables, the personalities of each participant has been purposefully matched to another, so there are less participant variables.
Design - Repeated Measures
- You need fewer participants overall beacuse each one takes part in both situations
- No participant variables as they are the same group of participants
- Higher rates of attrition because they are involved for longer
- Order effects: participants behaviour may change as a result of taking part in two conditions, rather than IV
- Higher chance of demand characteristics as if participants are in both conditions, they may guess the aims of the experiment
HOW TO OVERCOME WEAKNESSES: Counterbalancing - This is where half pf the participants complete the task in one order (A then B) and the other half complete the task in the reverse order (B then A). This would mean that the order effects would rule themselves out.
How does misleading information affect EWT? (1)
A leading question is...... A question phrased in a way that prompts a particular answer. Eg. What colour was the man's hat? It suggests that the man was actually wearing a hat.
LOFTUS & ZANNI (1974)
AIM: To investigate whether memory could be influenced by the wording of a question.
Experiment 1: 45 students shown a series of car crash videos and asked to complete a questionnaire. Key question - How fast were the cars travelling when they ____ into eachother? (Smashed/collided/bumped/hit/contacted).
Experiment 2: 150 students questionnaire was used using either 'hit' or 'smashed'. Key question: "Did you see any broken glass?" There was no broken glass in the film.
How does misleading information affect EWT? (2)
Experiment 1: Averages of estimated speed: Smashed - 40.8 mph. Collided - 39.3 mph. Bumped - 38.1 mph. Hit - 34.0 mph. Contacted - 31.8 mph
Experiment 2: 'Smashed' group = 32%. 'Hit' group = 14%. Control group = 12%. Indicating that they had seen broken glass.
This research supports the idea that the wording of a question can give misleading information which can influence subsequent answers
Evaluation of Loftus & Palmer
- It has very high internal validity because lab experiments are very controlled, so the demand characteristics/extraneous variables will be low. Therefore, IV determines the DV.
- It may lack eco-logical validity because watching a video isn't the same as witnessing an event in real life. Therefore the results may not demonstrate valid eye-witness testimony. In real life, EWT is in controlled conditions eg. court cases.
- The population validity may be poor because university students may be very good at remembering things, whereas the 'general population' may not - may show demand characteristics or be used to it.
The Cognitive Interview (1)
TRADITIONAL INTERVIEW: Police led/in control. Set questions in a set order, which is not always logical for the EW. Short, closed questions, one specific question at a time. may interrupt EW with follow up questions - may disrupt flow of EWT.
4 main strategies:
- REPORT EVERYTHING - Even if it seems 'trivial' as that may trigger other important details in memory.
- CONTEXT REINSTATEMENT - Try to get EW in a similar frame of mind as they were at the event, as this may trigger other details. Eg. Feelings? What was one thinking?
- CHANGE PERSPECTIVE - Ask EW to report what the event may have looked like from other EWs or even the criminal's PoV.
- REVERSE ORDER - Ask EW to try and report the end back to the beginning - might help the recovery effect (tend to remember more recent information)
The Cognitive Interview (2)
Why does it work?
ENCODING SPECIFICITY - is the principle behind RE and CR. The idea being that the more consistent the cues are, at the time of encoding and retrieval, the more likely it is that you'll get accurate results.
VARIED RETRIEVAL - is the principle behind CP and RO. The idea is that there are lots of different roots of retrieval in your memory, so going down as many roots as possible will be more productive in terms of getting accurate information.
Strengths of CI
CI technique is effective:
- Meta-analysis: Kohnken et al (1999). Analysed 53 studies of CI. Average increase of 34% in the amount of accurate recall when using CI then compared to SI.
- Real life: Stein & mermon (2006) - Study of CI in Brazil. participants saw a video of abduction. CI led to an increase in forensically rich information.
- Real life: Milne & Bull (2002) - 2 techniques of RE and Cr when combinned lead to better recall than SI.
Weaknesses of CI
Criticisms of these studies:
Most of these studies lack eco-logical validity. They take place in labs and involves artificial tasks. Eg. Watching videos and being tested on recall. Cannot be generalised to real life. Lacks population validity - universty students.
Criticism of the CI technique:
- Time - In real life, police probably don't have the time to conduct CIs and to be trained to use CIs.
- Some phrases are more effective than others - CP and RO are less effective at improving recall than SI.
- Young children - CI may not be effective for children as they may be confused or not understand techniques such as CP and RO.
Mnemonic Techniques - Visual
- Method of loci - Visualise objects/facts to be remembered in different locations along a familiar route eg. around the house. The locations act as a cue to help you recall them when remembered.
- Pictures of words - For words/facts to be remembered, pair them up with an image - act as a cue.
- Mind maps - Often using different colours, visually organising information - making links between different concepts to make associations in memory.
Dual-coding hypothesis: Words and images coded separately. Words are encoded twice, once as a word, once as an image.
Working memory: Encoding things visually and acoustically means we make use of both 'slave systems', increasing chance of transferring to LTM
Mnemonic Techniques - Visual (R)
Paivio: Concrete (things we can see) words remembered better than abstract - why? beacuse its easier to visualise, so dual-code.
Bower: 100 cards with pairs of words on. Half of participants asked to visualise, half of them not. On cued recall, imagers remembered 80%. Non-imagers 45%.
STRENGTH: Most are lab studies, which has good internal validity. More control over variables - IV causes DV
WEAKNESSES: Poor ecological validity, as it is an artificial setting. cannot be generalised to real life.
Mnemonic Techniques - Verbal
- Acronym: Abbreviations or words formed from the initial letters of words to be remembered. Eg. NHS, CBT, ROY G BIV.
- Acrostic: A phrase, a sentence or a poem is formed, where the first letter in each line corresponds to the first letter of words you want to remember. Eg. B E C A U S E - Big Elephants Always Use Small Exits
- Rhymes or Songs: Putting things that you need to remember to a rhythm or tune. Eg. Teach ABC by using 'twinkle twinkle, little star'. Making raps.
- Chunking: take a large amount of information and chunk it into shorter bits to remember. Eg. Remembering a phone number.
Creates more links between things to be remembered and things already in memory more quickly, so there are more ways it can be retrieved.
Helps with visualisation
Elaboration. Eg. Deeper encoding (semantic), not just repitition. Speeds up entry to LTM.
Mnemonic Techniques - Verbal (R)
There are no controlled studies, but there are anecdotal evidence. Eg. Students/teachers use these and they work (for them).
Don't know if we can trust what they say - not scientific. It lacks external validity.
Mnemonic Techniques - Understanding/Organisation
- Categorising words: Make deeper links to words or facts that we want to remember by organising them into categories of related words or facts.
- Creating stories: Where we give information deeper meaninngs by putting it into the context of a larger story.
- Semantic/deeper encoding - By giving things meaning, we encode them semantically - greater chance og getting into LTM
- Also, simply think about it for longer - Spending more time rehearsing - easier to remember.
Mnemonic Techniques - Understanding/Organisation (
BRANSFORD & JOHNSON - Doing the laundry. 1/2 were informed the meaning, 1/2 were not. Recall was better if meaning was known.
BOWER ET AL - 112 words, if organised into hierarchies, recall was 2-3 times better.
Slightly more realistic
Low ecological validity - artificial setting
Mnemonic Techniques - Non-Memory Strategies
- Context reinstatement: Thiis is where we try to recall information in the same or similar place as the place we encoded the information. Environmental cues act as triggers for recall.
- State of mind: Trying to recall in a similar and emotional state as the time of encoding.
- Context dependent recall - If the environment is similar at time of encoding/recall - context cues act as triggers for memory.
- State dependent recall - If emotional state is similar - internal cues to trigger memory.
Mnemonic Techniques - Non-Memory Strategies (R)
GODDEN & BADDELEY - deep sea-divers, list of words, dry land or 15ft underwater. 30% recall in same context.
GOODWIN ET AL - Hiding bottle when drunk, could only find when drunk.
- Took place in a natural environment
- Lacks ecological validity - learn lists underwater, not realistic