Short Term Memory (9/22)

Memory

mental process that enables us to retain and use info over time

What was the significance Atkinson & Shiffrin (‘68)

info passes through three distinct structures and three distinct processes

based on the belief that memories are processed the same way that a computer processes info

What is the Aktinson & Shiffrin Model?

Three Structures of the A-S Model

• Sensory → STM → ← LTM

What are the three structures of the A-S Model

Sensory Memory: 

STM

LTM

Sensory Memory (A-S Model)

storage of belief sensory events, such as sights, sounds, & tastes

STM (A-S Model)

temporary storage system that processes incoming sensory memory

LTM (A-S model)

the enduring storage of information

What are the three processes of the A-S model?

Encoding

Storage

Retrieval

Encoding (A-S model)

the mental process by which information is transformed into a form that can be easily entered into and retained by the memory system

Storage (A-S Model)

the process of storing information in memory for use at a later time

Retrieval (A-S model)

the recovery of information from our memory so that we are consciously aware of

What are the two types of Sensory Memory?

Iconic (visual) sensory memory

Echoic (auditory) sensory memory

Iconic Memory

immediate, brief memory of a visual image

the shortest-term element of memory

Persistence of Vision

Persistence of Vision ( part of sensory memory)

a sensation lasts for a fraction of a second in memory beyond its real-world duration

Echoic memory (of sensory memory)

momentary sensory memory of auditory stimuli

if attention is directed elsewhere, sounds and words can still be recalled w/in 3 or 4 seconds

→ stores the tail-end of the question temporarily while earlier parts of the message are being processed

estimates of echoic duration are often distorted by retrieval from short term memory

What is the significance of George Sperling et al. (‘60)

conducted classical research on the characteristics and processes of visual sensory memory

Results:

suggest all registered, but some (memories) were no longer available at the time or report (supports decay)

suggested visual sensory store decays rapidly & is relatively large

suggests visual sensory memory lasts about 250-300ms (relatively short)

Short Term Memory (STM)

store house for limited amounts of information for brief periods of time

What is the duration of STM?

Brown-Peterson Paradigm

• participants had 5% recall after 18 secs

• info decays from STM w/in 20 secs

• rehearsal is important in maintaining info - disruption to rehearsal by a distractor task greatly effects recall

Waugh & Norman (‘65)

• does not support decay, but interference

What are problems with the Brown Peterson Paradigm

task prevented rehearsal which is a potential sources of interference

→ retroactive interference

Interference from the experimental situation

→ proactive interference

Retroactive interference

occurs when newly learned information interferes with the retrieval of old info

Proactive interference

occurs when previously learned information interferes with the learning of new information

What is the capacity of STM?

can process large amounts of info

creates bottle-neck effect

George Miller (‘56)

• results: remembered on average 7 , suggests STM’s magic number is 7 ± 2

Bower & Springston (‘70)

• Chunking (or recoding)

• if words are reordered into a way that is more meaningful, capacity is maximized

Luck & Vogal (‘97)

• suggested STM capacity may be limited to as low as 4 components when STM is not linguistic nature (i.e blocks)

What are the three conditions for important recoding (or chunking) (STM)

1. sufficient time or resources needed to apply recoding scheme

2. must be recoded into something meaningful

3. if the recoding scheme is well learned it requires less time and resources

What are the two position effects?

primary and recency effect

Primary Effect (position effects)

recalling the first items better than the middle items

• probability decreases as the number of items increases

• result of rehearsal and encoding into long-term memory

rapid presentation eliminated primacy but preserves recency

Recency effect (position effects)

recalling the last items better than the middle items

• probability is not affected at the number of items increases

• result of items still w/in STM

delayed recall eliminates recency but preserves primacy