memory Flashcards
sensory memory
•initial contact for stimuli, it’s only capable of retaining information for a very short time.
short term memory
•the information we are currently aware of or thinking about. the information found in short term memory comes from paying attention to sensory memory.
long term memory
•continual storage of information which is largely outside of our awareness, but can be called into working memory to be used when needed.
capacity
indicates the amount of information that can be stored in memory. It is represented in terms of “bits” of information.
duration
refers to how long a memory trace can last, LTM potentially last forever but STM doesn’t last very long.
coding
information has to be input in memory in some form. It is the form in which a memory trace is created.
Can be stored in different forms:
-visually
-acoustically
-semantically
jacobs (1887) digit span - research into capacity of STM
conducted an experiment using a digit span test, to examine the capacity of short-term memory for numbers and letters.
Participants had to repeat back a string of numbers or letters in the same order and the number of digits was gradually increased, until the participants could no longer recall the sequence.
Jacobs found that the student had an average span of 7.3 letters
Miller (1986) - research into capacity
he reviewed existing research into short-term memory. He said that we can hold 7 +/- ‘items’ in short-term memory.
our short-term memory stores ‘chunks’ of information rather than individual numbers or letters.
Capacity of stm
7 +/- 2
Capacity of LTM
Unlimited
Peterson & Peterson (1959) - research into duration of STM
- participants were given a consonant syllable and a three digit number ( eg THX 512). They were asked to recall the consonant syllable after intervals of 3,6,9,12,15 or 18 seconds. To prevent rehearsal p’s we’re asked to count backwards from their 3 digit numbers.
- after 3s ps were on average 90% correct at 18s only 2%.
- suggests the duration of STM is less than 18s, if rehearsal isn’t interrupted.
Bahrick et al ( 1978) - research into duration of LTM
- tested photo recognition and free name recall from the p’s high school year book.
- P’s tested within 15 years of graduation were 90% accurate, after 48 years recall declined to 70%.
- free name recall was not as good as photo recognition after 15 years this was 60% accurate dropping to 30% after 48 years.
- suggests that the duration of LTM can last a very long time.
Duration of STM
18-30s
Duration of LTM
Unlimited
Baddeley (1966) - research into coding
- Participants were shown a list of words and had to recall them in the correct order.
- To test STM ps recalled the words immediately after hearing them, whereas a time interval of 20 minutes was given for LTM recall.
- found participants had difficulty remembering acoustically similar words in STM, semantically similar words got confused in LTM.
- suggests information is coded acoustically in STM and semantically in LTM.
Coding in STM
acoustically
Coding in LTM
Semantic
Central executive
- directs attention to tasks, decides what working memory pays attention to.
-controls the ‘slave systems’ ( other 3 components)
phonological loop
- limited capacity holds 2 seconds worth of information
•deals with auditory information
•codes acoustically
•further subdivided into phonological store(words heard) and articulating loop (holds words seen)
viso-spacial sketch pad
•visual and spacial information is stored here
•visual - what things look like
•spacial- relationships between things
•limited capacity
•subdivided into visual-cache (stores info about visual items) and inner scribe (for spacial relations and which stores the arrangement of objects)
baddeley and hitch (1974) phonological loop and viso-spacial sketchpad
Aim : to investigate if participants can use different parts of working memory at the same time.
Method : p’s were asked to perform two tasks at the same time - a digit span task which required them to repeat a list of numbers, and a verbal reasoning task which required them to answer true or false questions.
Results: As the number of digits increased in the digit span tasks, participants took longer to answer the reasoning questions.
Conclusion : the verbal reasoning task made use of the central executive the digit span took made use of phonological loop.
episodic buffer
•baddeley later added the episodic buffer as he realised the model needed a more general store.
•slave systems deal with specific types of info.
•buffer extra storage system but with limited capacity.
•maintains a sense of time sequences- recording events that are happening.
types of long term memory
•episodic
•semantic
•procedural
episodic memory
part of the LTM responsible for storing information about events that we have experienced in our lives. It involves conscious thought and is declarative.
• They are associated with the hippocampus and right prefrontal cortex
found by tulving (1994).
semantic memory
•responsible for storing information about the world. this includes knowledge about the meaning of words, as well as general knowledge.
• It involves conscious thought and is declarative - This means it has to be consciously recalled.
•They often start as episodic memories but they are not time stamped.
procedural memory
•responsible for knowing how to do things/ carry out complex tasks ie memory of motor skills.
•it does not involve conscious thought and is non-declarative.
interference
when two pieces of information conflict with each other, this can be a result in forgetting one of or both pieces of information or a distortion of memory
types of interference
• retroactive
• proactive
retroactive interference
happens when a newer memory interferes with an older one.
proactive interference
occurs when an older memory interferes with a newer one
Retrieval failure
Failure to find an item of information because you have insufficient cues
Context-dependent memory
refers to improved recall of specific episodes or information when contextual cues relating to the environment are the same during encoding and retrieval.
State-dependent memory
refers to improved recall of specific episodes or information when cues relating to emotional and physical state are the same during encoding and retrieval.
types of misleading information
• leading question
• post event discussion
Loftus and palmer (1974) - leading questions
-P’s watched a video of a car crash and asked a specific question about the speed of the cars, but changed the verb in the question.
-They found the estimated speed was effected by the verb eg smashed = 40.5mph contacted = 31.8mph.
-Shows the accuracy of EWT is affected by leading questions, a single word can significantly affect accuracy of judgements.
Gabbert et al (2003) - post event discussion
- consisted 60 students and 60 other adults
- p’s watched a video of a girl stealing money from a wallet, either tested individually (control) or in pairs (co-witness). P’s in the the co-witness group were told they had watched the same video but they had seen different perspectives of the same crime and only one person actually witnessed the girl stealing. P’s in the co-witness group discussed the crime together.
- 71% of the witnesses in the co-witness group recalled info they had not actually seen and 60% said that the girl was guilty, despite the fact they had not seen her commit a crime.
- these results highlight the issue of post-event discussion and the powerful effect this can have on the accuracy of eyewitness testimony.
Anxiety
has a curvilinear relationship between stress and performance ( inverted u theory) if too high or too low it leads to poor performance/recall
Yerkes and Dodsen - inverted U theory
•the inverted U theory states that performance will increase with stress, but only to a certain point where it decreases drastically.
• this means that anxiety can have both a positive and negative effect on someone’s ability to accurately recall EWT
weapon focus effect
in violent crimes arousal may focus the witness on more central details (such as a weapon) of the attack than the more peripheral details.
Johnson and Scott (1976) - anxiety has a negative affect
•p’s thought they were taking part in a lab study. while in waiting room p’s heard an argument in the next room, the low anxiety condition had a man walk through with a pen and grease on his hands whereas the high anxiety condition the man walks through holding a knife that was covered in knife.
• p’s picked out the man from 50 photos; 49% of the low-anxiety identified him. whereas only 33% had accurate EWT in the high anxiety condition.
Yuille and Cutshall - anxiety has a positive affect
• studied a real life shooting, the shop owner shot a thief dead, 13 took part in this study. interviews took place 4-5 months after and were compared with the original police interviews made at the time of the shootings. Accuracy was determined by the number of details reported in each interview. P’s were also asked to rate how stressed they felt at the time on a 7 point scale, and if they had any emotional problems since the event.
•p’s we’re very accurate in their accounts and there was little change in EWT after 5 months. P’s who reported highest levels of stress were most accurate.
stages of the cognitive interview
•report everything
•Reinstate the context
•Reverse the order
•change perspective
report everything
•take notes on everything.
•details act as cues which may trigger important memories.
reinstate the context
• taken back to the scene to trigger memory
• based on context-dependent memory, triggers a route into memory
reverse the order
•chronological shift (disrupts schema)
•this breaks up the natural flow of memory, checking it’s right
change perspective
• someone else’s point of view
• disrupts the effect of expectations and schemas on recall
leading questions
a question in which the wording can distort the memory or influence the answer.
post event discussion
when the event is discussed afterwards and it could distort memory.
Godden & Baddeley
• deep sea divers learnt a list of instructions and later recalled:
- water,water
- water, land
- land, water
- land, land
• accurate reacall was 40% lower in conditions 2 and 3 than in 1 and 4
• due to lack to context cues at time of recall
Carter & Cassaday
• ps learnt list of words and later recalled :
- on drugs, on drugs
- on drugs, sober
- sober, on drugs
- sober,sober
• recall was significantly worse in conditions 2 and 3 compared to 1 and 4
• when the cues at encoding are absent at retrieval then there is more forgetting
mcGeoch and mcdonald - retroactive interference
• Studied retroactive interference by changing the amount of similarity between two sets of materials which p’s had to recall. Participants had to learn a list of words until they could remember it with 100% accuracy.
• They then learned a new list of either synonyms, nonsense syllables or numbers.
• Results:
Synonyms = 12% recall
Syllables = 26% recall
Numbers = 37% recall
