Introduction to Memory
Two Types of Memory
Long Term Memory- Permanent memory store.
Short Term Memory-Temporary memory store.
- Coding-The form in which the information is stored.
- Capacity-The amount of information that can be stored.
- Durartion-The length of time the information can be held for.
STM- Coding - Acoustic, Duration-18-30 seconds, Capacity - 7+/-2 items
LTM- Coding-Semantic, Duration - Lifetime, Capacity- Unlimited.
Coding - Baddeley Research
- 4 groups
- list of words which participants had to remeber the list of words were acoustically similar and acoustically dissimilar and also semantically similar and semantically dissimilar.
- STM recall worse with acoustically similar
- LTM recall worse with semantically similar
- Limited Application
- Artifical Material
Capacity - Jacobs and Millers Research
- Developed a technique to measure Digit span
- The researcher gives 4 digits and then the participant is asked to recall these in correct order and keep going increase the number or digits
- Mean span - 9.3 items and 7.3 letters
Evaluation - Conducted a long time ago no control over extraneous variables.
- Capacity of STM is about 7 items plus or minus 2 and we remember things by chunking
Evaluation- Overestimated the amount of chunks - Cowan 2001 - only 4 chunks Miller overestimated.
Duration- Bahrick and Petersonx2 Research
Peterson and Peterson Research
- Participants given a 3 digit number to count backward by 3 from to prevent mental rehearsal whilst learning a constant syllable.
- STM has a short duration
Evalutation- Lacks validity as it doesnt reflect real-life memory activities.
Bahrick - Participants were asked to recall and photo recognition of pictures in a year book
- 15 years after - 90% photo recognition
- 48 years after- 70% photo recognition
- LTM- long duration
Evaluation - High internal validity -meaningful memories however confounding variables not controlled.
Multi-Store Model - Atkinson and Shiffrins
- Input from the enviroment can be iconic-visual, echoic-sound and etc.
- Memories are not directly recalled from LTM.
- We can keep information in our STM as long as we rehearse it if we rehearse it long enough it moves to LTM.
- When we want to recall material it has to move from LTM-STM this is retrieval.
Sensory Register/Memory- Coding-All types, Duration-Less than 1/2 a second, Capacity- Large.
Evaluation of MSM
- Research that supports MSM uses artifical material which not meaningful so it lacks external validity
- There is more than one type of LTM- episodic, semantic and procedural.
- Supporting Research Evidence- STM and LTM are different separate stores which are independent of each other -Baddeley Research.
Working Memory model
Phonological loop-deals with Auditory Information. Phonological Store- Inner ear stores the words you hear. Articulatory Process- Maintenance rehearsal repeat words mentally.
Central Executive- Monitors incoming data and allocates slave systems to task it has a limited storage capacity.
Visuo-Spatical Sketchpad- Deals with Visual Information. Visual Cache- Stores visual data. Inner Scribe- records spatial arrangement.
Episodic Buffer- Temporary store on information integrating the visual,spatial, and verbal information, storage component of the central executive. Links to the LTM.
Evaluation of WMW
- Central executive is the most important but least understood- not fully explained. WMW hasnt been fully explained.
- Dual task performance- Participants had difficulty doing two visual task at the same time compared to one visual and one verbal suggest separate slave systems.
- Clinical evidence- KF had poor STM ability for verabl but could process visual information normally only phonological loop damaged which suggest separates stores.
Different type of LTM
- Procedural-Actions/skills no conscious effort to recall.
- Episodic- Events from your own lives, time stamped and takes conscious effort to recall memories
- Semantic- Facts and knowledge of the world, not time stamped, and continously added to.
- Clinical Evidence- Clive Wearing - episodic memory impaired but semantic memory and procedural unaffected supports the fact that there are different memory stores in LTM.
- Brain Scan Studies- Left prefrontal cortex- Semantic Right prefrontal cortex- Episodic. Physical reality of different type of LTM- Validity.
- Real Life Application- Psychologist can target certain kinds of memory in oder to improve people's life specific treatments can be developed.
Forgetting Theories- Interference Theory
Interference Theory - Two memories which are similar conflict with other and cause one or both to become distorted which results in forgetting.
Retroactive- Newer memories interferes with the old. Example- A teacher has learnt so many names of her new class that she can not remember the names of her old class.
Proactive- Older memories interfers with the new. Examples- A teacher has so many names of her old class so she cannot remember the name of her new class.
- Supported by lab experiments - McGeoch and Mcdonald found that recall was worst for first list when the second set of words was similar to first. Interference the strongest when material is similar.
- Rugby players were asked to recall the names of the teams they had played, accuracy was dependent on the teams they had played in the meantime not how long ago - real life appilcation.
- Lab experiments- Are more likely to create interference than in real because of artifical materials.
Forgetting Theories- Retrieval Failure Theory
Retrieval Failure Theory - We need cues to accsess our memories all memories are available but they may not be accessible if we dont have the relevant cues.
Cues- triggers on information which may be meaningul or indirectly linked by being encoded at the time may be intenal/environmental.
Context Dependent Forgetting - Recall is more likely if the context in which you learnt the material and recall the material is the same if they dont match accurate recall is less likely. Baddelely- accurate recall was better for sea divers when recall and learning took place in the same context. Accurate recall was 40% lowe in non-matching conditions.
State Dependent Forgetting-Carter/Cassaday Antihistamines drugs recall is more accurate if the internal state matches.
- Context effects are not that strong in real life.
- Context effect related to the kind of memory that is being tested it doesnt affect recognition
- Supporting evidence- Sea divers/antihistamine drugs. High Internal Validity
Factors affecting Eyewitness Testimony
Factors- Leading questions - The way a question is phrased can provide a biased answer or response.
Leading Q - Loftus and Palmer 'How fast were the car going when they----------'
Smashed highest speed- 40.8 Contacted- Lowest speed- 31.8
Response bias explanation - Wording of question has no real effect on memory it just influences how they decide to answer.
Loftus and Palmer conducted a second experiment 'Was there any broken glass' but there was none. With the verb smashed people were more likey to say that had seen broken glass. Supports Subsitution explanation where the wording of the leading question actually changed the persons memory.
Factors affecting Eyewitness Testimony
Post Event Discussion
EWT become contaminated when you combine misinformation with their own memories.
Gabbert-Participants watched a crime from different points of veiw so they saw different things, participant then discussed before a test of recall. Control group had no discussion. 71% ppts who discussed mistakenly recalled aspects of the event. 0% of the control group.
Informational Social Influence and Normative Social Influence at work -phenomenon memory conformity.
- Real life application - improves the way legal systems work.
- Task Artifical- lacks the stress/anxiety factor of recall.
- Demand Characterisitics.
The effects of Anxiety
Anxiety- State of emotional (worried thoughts and tension) and physical (increased heart rate and sweatiness) arousal influences you accuracy and detail of EWT.
Johnson and Scott- Ppts in low anxiety condition - man walked out with pen with grease on it. High anxiety condition- man walked out with paper knife with blood on it and sounds of breaking glass. After they were asked to do a recognition test - 50 photos to identify the man. 49% of those in low anxiety condition were able to recall the man only 33% in high anxiety condition. Witnesses attention narrows to focus on weapon because it is a source of anxiety.
Anxiety - Positive Effect on EWT
Anxiety can have a positive effect on recall. Flight/Fight response increases alertness improves memory of the even- aware of the situation.
Yuile and Cutshall- Field study on a real life shooting in canada. Intervewied 4-5 months after. Accuracy was determined by detail, also had to rate how stressed tey were.
Witnesses very accurate in their account. Ppts who recorded the highest level of stress were most accurate 88% compared to 75% for less stressed group.
- Weapon focus may not be relevant
- Field studies lack control
- ethical issues -psychological harm
Yerkes Dodson Law
A method of interveiwing EWT to help them retrieve more accurate memories.
4 Main Techniques
- Report everything
- Reinstate the context
- Reverse the order
- Change Perspective
Enhanced Cognitive Interveiw -Additional elements of the cognitive interveiw to focus on the social dynamics of intercation for example when to have eye contact and when not to.
- Time consuming
- some elements more valuable than others combination of report everything and reinstate the context produces better recall than anu other.
- Research support for the effectivenes of ECI meta analysis - ECI consistenly provided more correct information