Memory Flashcards
Memory
The storage system in the brain that holds information about stimuli, events, images etc. after the original stimuli are no longer present.
Primacy effect
An individual’s tendency to remember the first piece of information they encounter due to it being processed and put in a long term memory.
Recency effect
Information that came last is remembered more clearly than those that came first. This information is held in a short term memory.
The multi-store model of memory
Information - sensory register - attention -rehearsal - short term memory - rehearsal - long term memory - retrieval
Capacity
The amount of information that can be stored in the memory store.
Duration
The length of time that information can be held in the memory store.
Coding
The way in which information is represented in the memory store.
Short term memory (STM)
Capacity: 7+/-2 items
Duration: 18-30 seconds (without rehearsal)
Coding: acoustic (by sound)
Long term memory (LTM)
Capacity: unlimited
Duration: up to a lifetime
Coding: semantic (by meaning)
Sensory register
Capacity: very large
Duration: milli seconds
Coding: modality specific
Sperling - Duration of the sensory register
- Flashed grids of letters then played a high, medium or low tone.
- Letters flashed for 1/20th of a second
- Participant had to report the top, middle or bottom row depending on the sound they heard
- They could only do this if the tone was within 1/3 of a second (very short duration)
Miller - Capacity of short term memory
- Digit span test
- Participants had to recall increasingly longer strings of digits
- Most people get 5-9 digits correct
Peterson + Peterson - Duration of short term memory
- Trigrams to learn
- Participants had to learn these trigrams and then recall back after counting backwards
- After 3 seconds 80% recalled
- After 18 seconds 10% recalled
- Artificial stimuli means study lacked ecological validity
Bahrick - Duration of long term memory
- Yearbook test
- 392 graduates were shown photos from their high school yearbook
- 60% could accurately match names to faces 47 years later
- High external validity because it investigated meaningful memories so would reflect a more ‘real’ estimate of LTM duration
Baddeley - Coding of STM and LTM
- Participants had to learn words that sounded the same (e.g bee, knee) or words that meant the same (e.g loud, noisy)
- Participants made mistakes on the sound words when STM was tested and meaning words when LTM was tested
- A strength is that it identified a clear difference between the two memory stores
- A limitation is that the findings could have limited application as word lists are artificial stimuli
Episodic memory
LTM store for personal events, including where, when, people, places. Must be consciously retrieved and it is time stamped.
Semantic memory
LTM store for knowledge of the world. Facts, concepts and meanings. Not time stamped and must be consciously retrieved.
Procedural memory
LTM store for knowledge of how to do things, including learned skills. Recalled without conscious effort and not time stamped.
Case study: HM
- HM had brain surgery to relieve his epilepsy
- The surgeons removed his hippocampus without realising that this would permanently damage HM’s LTM
- His episodic and semantic but not his procedural
Case study: Clive Wearing
- Episodic memory damaged
- Still had some semantic knowledge (e.g. that he is married to his wife)
- Kept most of his procedural memories
- Worst case of amnesia
Working memory model
Focuses on short term memory. It is the explanation of the memory used when working on a task. Concerned with the “mental space” active when we are temporarily storing and manipulating information.
Stores in working memory
Central executive, phonological loop, visuo spatial sketchpad and episodic buffer.
Central executive
Monitors and coordinates all other mental functions in working memory. Controls attention and determines which sub-systems take on different tasks.
- Supervisory role
- Monitors incoming data
- Does not store information
- Limited processing capacity
Phonological loop
Codes speech sounds in working memory, typically involving maintenance rehearsal.
Phonological store: stores words you hear
Articulatory process: maintenance rehearsal and capacity is 2 seconds worth of what you can say
Visuo - spatial sketchpad
- Has a capacity of 3-4 items (limited capacity)
- Temporary store for visual and spatial information
- Visual cache stores visual information
- Inner scribe records arrangement of objects in the visual field
Episodic buffer
Receives input from many sources, temporarily stores this information and then integrates it in order to construct a mental episode of what is being experienced. Send information to LTM and maintains a sense of time sequencing.
- Added by Baddeley in 2000
- Limited capacity of about 4 chunks
Dual task studies
Doing two things at once.
Examples:
- Tracking a moving light while problem solving (different stores used)
- Saying a random number whilst solving problems (hard to do as both require CE)
Evidence to support the WMM
- A psychologist (in 1993) used a PET scan to record brain activity when participants were performing verbal tasks (using phonological loop) or visual tasks (using the visuo-spatial sketchpad) and found that very different areas of the brain were active during each task.
- KF case study supports the existence of separate visual and acoustic memory stores
- Dual task studies
Limitation of the WMM
We don’t know a lot about the central executive. It is hard to research because we cannot isolate it in the same way as the other stores.
Interference
One memory disrupts the ability to recall another memory.
Proactive interference
Older memories from previous learning disrupt the recall of newer memories.
Retroactive interference
Newer memories disrupt the recall of previously stored memories.
What are the effects of similarity in interference?
In both proactive and retroactive interference, the interference is worse when the memories are similar.
Retrieval failure
Information is in LTM but cannot be accessed. It cannot be accessed because the retrieval cues are not present.
Encoding specificity
Memory is most effective when information available at coding is also present during retrieval . This information acts as cues that trigger our memories. We forget in the absence of these cues.