Memory:
Living with Yesterday
Different Types of Memory
•	We have different memory systems for different purposes
•	Each system has a
–	Duration
•	How long memories last
–	Capacity
•	How much information can be stored
Three Memory Stores
Sensory Memory
•	Properties
–	Very short duration (less than 1 second)
–	Large capacity
•	Lingering activation in perceptual areas of the brain
•	Studied using the Sperling technique
The Sperling Technique
•	Letters flashed quickly
•	Arrow appears next to one row
•	Write down letters from that row

What Sperling Showed
•	Full report (first trial) 
–	3-4 correct
•	Partial report (later trials)
–	3-4 correct (any row)
•	SM has a large capacity and short duration
•	Attention plays a key role in moving information from SM to STM
Short-Term Memory
•	Properties
–	Short duration (a few seconds)
–	Small capacity (7+2 items)
•	Useful for
–	Remembering telephone numbers
–	Language use
–	Getting information to long-term memory
Extending STM
•	We use strategies to extend STM
•	Increasing capacity
–	Chunking
•	Increasing duration
–	Rehearsal
Chunking:
Extending STM Capacity
•	By combining items into meaningful “chunks,” we use fewer slots of STM	
The Memory Curve
Rehearsal: 
Extending STM Duration
•	Silent repetition keeps STM refreshed
•	Works until you are interrupted
•	Rehearse enough, and STM moves to LTM
–	Memory curve
•	Primacy effect (LTM)
•	Recency effect (STM)

Long-Term Memory
•	Properties
–	(Very) long duration
•	Hours to decades
–	(Very) large capacity
•	Always room for new memories
Types of LTM
Implicit versus Explicit LTM
•	Explicit memory
–	Conscious awareness; easy to verbalize
–	Includes semantic and episodic
•	Implicit memory
–	No conscious awareness; hard to verbalize
–	Includes skills or habits (how to ride a bike)
Explicit LTM: 
Semantic versus Episodic
•	Semantic
–	Word meanings (a dog is an animal)
–	Concepts (heat rises)
–	General facts (my dog is named Walter)
•	Episodic
–	Events that occurred to you (buying a dog)
–	Include context (when, where)
Working Memory (WM):
How the Mind Uses STM
•	We manipulate the contents of STM
–	Problem solving
–	Planning
•	WM includes
–	Central executive 
–	Verbal STM
–	Visuospatial STM
–	Other STMs

Foundations of Memory
•	Long-term potentiation (LTP)
–	Links between related neurons are strengthened
•	Genes and memory
–	Knockout mice
•	Different genes for different memory types
–	Humans
•	ApoE gene related to memory and Alzheimer’s
Making Memories: Encoding
Making Memories: Code
•	Memories can be stored in different formats
–	Based on anticipated use
Consolidation
•	Consolidation is the strengthening of memories
–	Results from frequent or long-term use
–	New memories are dynamic
–	Consolidated memories are structural
•	Consolidation of explicit memories occurs in the hippocampus
Depth of Processing
•	We can process new information in simple (shallow) or complex (deep) ways
–	Shallow: based on sensory characteristics
–	Deep: based on meaning
•	Complex processing leads to better memory
Breadth of Processing
•	We can encode new information in simple or elaborate ways
–	Simple encoding: repeating information
–	Elaborative encoding: creating connections to existing knowledge
•	Elaborative encoding leads to better memory
Flashbulb Memories
•	Emotionally charged, episodic memories
–	September 11, 2001
–	Kennedy assassination
–	Space Shuttle Columbia disaster
–	Birth of a sibling
•	Very vivid and accurate
–	High level of confidence
–	But, accuracy does decrease over time

The Act of Remembering
•	Memory is a constructive process
–	Not like a videotape or DVD
–	Biases and expectations can influence memory
•	False memories
–	Memories of events that did not occur
Recall and Recognition
•	Recall
–	Intentionally bringing LTM into STM
–	“Who was Carter’s Vice President?”
•	Recognition
–	Matching an input to a stored memory
–	“Was Mondale Carter’s Vice President?”
•	Recall is typically harder than recognition
Forgetting
•	Decay
–	Memories fade away over time
•	Interference
–	Retroactive: new information makes it harder to remember old information
–	Proactive: old information makes it harder to learn new information
Amnesia
•	Retrograde amnesia
–	Impairment of memories before onset
–	Infantile amnesia
–	Soap opera plot device
•	Anterograde amnesia
–	Impairment of memories after onset
–	Patient H.M.
–	Movie: Memento
Improving Memory
•	Mnemonic devices
–	Interactive images
–	Method of loci
–	Pegword system
–	Acronyms/initialisms
–	Hierarchical organization
•	Spaced practice
•	Depth and breadth of processing