Cognitive - Types of Memory Flashcards
What is Sensory memory?
The system that holds information in an unprocessed form, where each sense has its own brief ‘storage system’
What is the capacity of Sensory memory?
As concluded by Sperling, about 9 or 10 items in the iconic (visual) memory
What is the duration of Sensory memory?
Fractions of a second
What is Short-Term memory?
System for storing information for brief periods of time
What is the capacity of Short-Term memory?
7 items (plus or minus 2) as concluded by Jacobs
Name and explain a study in the capacity of STM
Miller
Participants had to recall a series of numbers ascending in the number of digits and found that the average units of information is the ‘magic number 7’ plus or minus 2.
What factors affect the capacity of STM?
- Reading aloud
- Rhythmic grouping
- Pronunciation time
Name and explain a study into the pronunciation time determining the capacity of STM
Baddeley (1975)
Reading speed of participants was measured and the participants were then presented with sets of 5 words (either 1 syllable or polysyllabic) and asked to recall them in order.
He found that participants could recall more short words than long words, positive correlation between reading speed and memory span, and they were able to recall as many words as they could articulate in 2 seconds
What is the duration of STM?
Around 20 seconds maximum
Name and explain a study into the duration of STM
Peterson & Peterson
Participants shown a series of trigrams (e.g CDW) and asked to recall them after ascending periods of time.
Found a 90% loss after 18 seconds
What factors affect the duration of STM?
- Maintenance rehearsal
- Amount of information to be retained
Name and explain a study into the amount of information as a factor affecting the duration of STM
Murdock
Presented participants with either 3 letters that can form a word (e.g. c a t) or 3 unrelated words.
Found the words to be recalled as with Peterson study (18 seconds) but because the 3 letters could be chunked together to make just 1 word, correct recall was 90% after 18 seconds
Name and explain a study into the encoding of STM
Conrad
Participants had to recall a series of letters, some acoustically similar (P, D, E) and some acoustically dissimilar (U,F,I).
Found that STM encodes acoustically (letters sounding similar were more easily confused than letters sounding dissimilar, despite visually looking different)
Name and explain a study looking at the type of encoding which is preferred by LTM and STM
Baddeley (1966) Participants given 4 word lists: -acoustically similar -semantically similar -acoustically dissimilar -semantically dissimilar
STM: made mistakes on words that sounded similar (supporting Conrad) concluded it encoded acoustically
LTM: made mistakes on words that were semantically similar, concluding it encoded semantically
What is the capacity of LTM?
No upper limit
What is the duration of LTM?
Seemingly unlimited duration
Name and explain a study into the duration of LTM
Bahrick et al 392 ex-highschool students tested in free-recall of the names of former class mates using photo prompts. They found that accurate recall was possible for periods as much as 50 years later (80% accuracy at 48 years)
Evaluate the studies into memory capacity, duration and encoding
They have low ecological validity as it is unlikely that on real life you would be asked to, for example, recall trigrams.
What evidence is there for both STM and LTM?
- Multi-store memory model
- Primary and Recency effect
- Amnesiac case studies
Name and explain a study into the primary and recency effect
Murdock
Gave 100 students lists of words to recall freely in 90 seconds.
Found that words and the start and end of the list were recalled most often (words at the beginning rehearsed into LTM, words at the end still in STM)
How do amnesiac case studies give evidence for both LTM and STM?
Most people with memory problems either have impairment of their STM or their LTM, usually not both
Give an example amnesiac case study
Henry M
Age 27 went under surgery attempting to cure his epilepsy. The surgeon removed an area known to be crucial to memory. Afterward Henry was unable to create new long term memories, but his STM remained in tact.
