Processes in Memory
Three step process…
1. Encoding: processing
information into the
memory
2. Storage: retaining
memories over time
3. Retrieval: getting
information out of
memory
Storage
• Memories can be stored for differing amounts of
time depending on how they are encoded
• The Atkinson-Shiffrin theory (three-stage model)
of storage includes 3 separate memory store
1. sensory memory - up to several seconds
2. short-term memory - up to 30 seconds
3. long-term memory - up to a lifetime
The Three-Stage Model
(attention)
(encoding)
Sensory Memory
• Holds information from ALL sensory input
• Large Capacity & Limited Duration
• Sensory memory enters into short-term memory
through the process of attention
• The longer we delay paying attention to sensory
information, the more we forget
• Iconic memory studied by George Sperling (1960)
Iconic
< 0.5 sec.
Echoic
3-4 sec.
Haptic
1-2 sec.
Short-Term Memory (STM)
• AKA Working Memory
• What we pay attention
to in sensory memory
moves into STM
• Limited Capacity &
Limited Duration
• Short-term memory
enters into long-term
memory through
encoding (rehearsal)
Limited Capacity of STM
• Studied by George Miller (1956)
• “The Magical Number Seven, Plus or Minus Two”
• 7±2
Increasing Capacity of STM
• Chunking: grouping items together into familiar or
easily manageable units
• We remember numbers better than letters
• Clustering: organizing information into categories
Limited Duration of STM
• Studied by John Brown (1958)/Margaret Peterson &
Lloyd Peterson (1959)
• Made participants work on a counting task
immediately after hearing meaningless threeconsonant syllables read to them
• Duration of short-term memory is less than 30 seconds
WITHOUT REHEARSAL
Working Memory Model
• Studied by Baddeley & Hitch
• Argues that the Atkinson-Shiffrin model
simplifies STM; STM is more complex
Long Term-Memory (LTM)
• What we rehearse in STM gets encoded into LTM
• Unlimited Capacity & possibly Unlimited Duration
• Automatically processed information bypasses
sensory memory & STM stores
• Contains multiple types of memories:
• Explicit Memory: facts and experiences; learned
consciously
• AKA Declarative Memory
• Types: Semantic & Episodic Memories
• Implicit Memory: skills & conditioning; learned
unconsciously
• AKA Non-declarative Memory
• Types: Procedural & Conditioned Memories
Types of Long Term-Memory
Flashbulb Memory
• Highly emotional memories of significant events
• Events can be positive or negative; usually unique
• Recall is more accurate and VIVID
• Produce a clear, strong, and persistent memory
• Does not mean that events are recollected correctly
• May include wrong information
• Where were you when:
• September 11th terrorist
attacks took place?
How Memory is Organized
• Schemas: A pre-existing mental framework that
helps people to organize and interpret information
• Prior encounters with the environment influence
the way that we encode, make inferences about,
and retrieve information
• Scripts: A schema for an event
• Very specific schema for a particular order of
expected events in a particular context
Long-term Potentiation
• How a memory is physically created in the brain
• At the neural level (neuron)
• Research has shown that new dendrites form and
create connections to other neurons when new
information comes into the brain
• As these neurons learn to fire together, they get
better at it and the connection between them
strengthens
• Making the memory stronger
• This creates an “express lane” for information
Memory Stores
Feature
Sensory
Memory
Working
Memory
Long-term
Memory
Encoding
Structural
Phonemic
Semantic
Capacity
Very Large
7±2 Chunks
Unlimited
(space)
Duration
(time)
(limited)
Up to several
seconds
Up to 30
seconds
Up to a
lifetime