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					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


				
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