Research on Coding, Capacity, and Duration

Flashcards about memory research on coding, capacity, and duration of STM and LTM.

Coding

The process of converting information in different forms to be stored in memory.

Alan Baddeley (1966a, 1966b)

baddeley tested the coding of STM AND LTM

Baddeley presented participants with lists of words that were either acoustically similar (e.g., cat, cab, can) or semantically similar (e.g., great, large, big). Participants were then asked to recall the words in the correct order either immediatly (STM) or after 20 min (LTM)

Findings: Participants found it diffcult recalling acoustically similar words in STM, but found it worse recalling semantically similar words in LTM. This suggests that STM primarily uses acoustic coding, while LTM primarily uses semantic coding.

Acoustic Coding

The encoding of information based on its sound. Shown to be dominant in STM.

Semantic Coding

The encoding of information based on its meaning. Shown to be dominant in LTM.

Joseph Jacobs (1887)- capacity for STM

Joseph Jacobs conducted research in 1887 to assess an individual's capacity for short-term memory

Studied digit span and found the mean span for digits was 9.3 items, and for letters was 7.3 items.

George Miller (1956)

Proposed that the capacity of STM is about 7 items, plus or minus 2. 7+-2 with chunking

Margaret and Lloyd Peterson (1959)

conducted a study in 1959 to investigate the duration of short-term memory (STM). In their experiment, participants were presented with consonant syllables (e.g., 'TGH') and then immediately asked to count backwards from a specific number. This counting task was designed to prevent rehearsal, which could prolong the duration of the information in STM.

The researchers found that STM has a limited duration when rehearsal is prevented. Participants' recall accuracy decreased significantly after a few seconds. After 3 seconds, participants recalled about 80% of the consonant syllables correctly, but after 18 seconds, recall dropped to 3%.

suggests that the duration of STM is approximately 18 seconds or less if rehearsal is prevented.

STM Duration

May be about 18 seconds, unless the information is verbally rehearsed.

Harry Bahrick et al. (1975)- duration of LTM

Studied the duration of LTM using high school yearbooks and found that LTM may last up to a lifetime for some material.

Participants were tested on their recall and recognition of names and faces of their former classmates.

After 15 years of graduating, participants showed about 90% accuracy in recognising names and faces. After 48 years it dropped to 70%.

for recall of names after 15 years it was 60% but after 48 it was 30%.

how is the LTM coded

semanticlaly

how is the stm coded

acoustically

how is the sensory register coded

sensory