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Storing
Memories

Explore how the brain encodes, stores, and organizes information across sensory, short-term, and long-term memory systems.

AP Psychology

What Is Memory Storage?

Memory storage is the process of retaining encoded information over time. Without storage, every experience would vanish the moment it ended. Psychologists study how the brain holds onto information, from a flash of light lasting milliseconds to a childhood memory lasting decades.

The Atkinson-Shiffrin Model

Sensory 0.5 – 3 sec Attention Short-Term ~20 sec Encoding Long-Term Unlimited Rehearsal Retrieval

The Atkinson-Shiffrin model (1968) proposes that memories flow through three stages: sensory memory, short-term memory, and long-term memory. Each stage has different capacity and duration limits.

Sensory Memory

Iconic Memory
Visual sensory store lasting about 0.5 seconds. Sperling's (1960) partial-report experiment showed we briefly hold all visual stimuli.
Echoic Memory
Auditory sensory store lasting about 3–4 seconds. This is why you can "replay" something someone just said even if you weren't fully paying attention.

Short-Term and Working Memory

Short-term memory (STM) holds roughly \(7 \pm 2\) items for about 20 seconds without rehearsal (Miller, 1956). Working memory (Baddeley, 1974) expanded this idea into an active processing system with multiple components.

Central Executive Directs attention Phonological Loop Verbal/auditory Visuospatial Visual/spatial Episodic Buffer Integrates info

Long-Term Memory: The Big Picture

Long-term memory has virtually unlimited capacity and can store information for a lifetime. Researchers divide it into two major categories:

Long-Term Memory Explicit (Declarative) Implicit (Nondeclarative) Episodic Personal events Semantic Facts & concepts Procedural Skills & habits Conditioning Learned responses

Explicit vs. Implicit Memory

Explicit (Declarative) Implicit (Nondeclarative)
Awareness Conscious recall Unconscious recall
Subtypes Episodic, Semantic Procedural, Conditioning
Example Remembering your 10th birthday Riding a bicycle
Brain Region Hippocampus Cerebellum, Basal ganglia
Damage Effect Amnesia impairs it Often preserved in amnesia

How We Encode into Long-Term Storage

1
Automatic processing: Some info is encoded without effort, such as time, space, and frequency of events.
2
Effortful processing: Requires deliberate rehearsal or study. Most academic learning falls here.
3
Deep (semantic) processing: Encoding by meaning produces stronger, longer-lasting memories than shallow (structural) processing.
4
Elaborative rehearsal: Connecting new information to existing knowledge rather than just repeating it (maintenance rehearsal).

Levels of Processing Framework

Shallow: Structural "Is the word in capital letters?" Intermediate: Phonemic "Does the word rhyme with 'brain'?" Deep: Semantic "Does the word fit the sentence?" → Better Recall

Strategies to Strengthen Storage

1
Chunking: Group related items together. "FBI-CIA-USA" is easier than "F-B-I-C-I-A-U-S-A."
2
Mnemonics: Use memory aids: acronyms, method of loci, peg-word system.
3
Spacing effect: Distribute study over time rather than cramming. Spaced practice beats massed practice.
4
Testing effect: Retrieval practice (quizzing yourself) strengthens storage more than re-reading.
5
Sleep consolidation: During sleep, the brain replays and consolidates memories, transferring them from hippocampus to cortex.

Example: Identifying Memory Types

Scenario: Maria is studying for her AP Psychology exam. She reads her notes three times (maintenance rehearsal), then creates a concept map linking new terms to what she already knows (elaborative rehearsal).

Re-reading notes
Maintenance rehearsal: Simply repeating information. Shallow processing: keeps info in STM but doesn't reliably transfer it to LTM.
Concept mapping
Elaborative rehearsal: Connecting new info to existing schemas. Deep (semantic) processing: creates durable long-term memories.

Example: The Case of H.M.

Henry Molaison had his hippocampus surgically removed to treat severe epilepsy. Afterward, he could not form new explicit memories (anterograde amnesia), yet he could still learn new motor skills, improving on a mirror-drawing task over days.

Lost
Ability to form new explicit memories: couldn't remember people he met minutes ago.
Preserved
Implicit procedural memory: motor skill improvement proved these memories don't depend on the hippocampus.

The Forgetting Curve

100% 80% 60% 40% 20% Retention % 0 20min 1hr 9hr 1day 6day Time Since Learning No review Spaced

Brain Structures and Memory Storage

Hippocampus
Consolidates new explicit memories. Acts as a "save button" that transfers short-term traces to long-term cortical storage.
Cerebellum
Stores procedural memories and classically conditioned responses, such as motor sequences.
Amygdala
Tags memories with emotional significance. Flashbulb memories are vivid partly because of amygdala activation.

Common Mistakes on the AP Exam

✕ Confusing STM with Working Memory
STM is a passive store; working memory is an active system with multiple components (Baddeley). They are related but not identical.
✕ Mixing Up Episodic and Semantic
Episodic = personal events ("my 16th birthday"). Semantic = general facts ("Paris is the capital of France"). Both are explicit.
✕ Assuming All Rehearsal Works Equally
Maintenance rehearsal (mere repetition) keeps info in STM but is poor for LTM. Elaborative rehearsal creates durable storage.

Summary of Memory Stores

Sensory Short-Term / Working Long-Term
Duration 0.5 – 4 sec ~20 sec (without rehearsal) Potentially permanent
Capacity Large but fleeting \(7 \pm 2\) items Virtually unlimited
Encoding Raw sensory input Acoustic, visual Semantic (meaning)
Key Researcher Sperling (1960) Miller; Baddeley Ebbinghaus; Tulving
Brain Area Sensory cortices Prefrontal cortex Hippocampus → Cortex

Question 1 of 5

George Sperling's partial-report experiment provided evidence for the existence of which type of memory?

Question 2 of 5

Which component of Baddeley's working memory model is responsible for directing attention and coordinating the other subsystems?

Question 3 of 5

A patient with hippocampal damage can still learn to solve a new puzzle faster with practice but cannot remember having practiced it. This best illustrates the distinction between:

Question 4 of 5

According to the levels of processing framework, which study strategy would produce the most durable long-term memory?

Question 5 of 5

The spacing effect suggests that long-term memory storage is best enhanced by: