Memory: Encoding, Storage, Retrieval (Key Concepts)

Encoding, Storage, and Retrieval (Three Basic Memory Processes)

  • Encoding – Converting sensory input into a form the brain can store.
  • Storage – Maintaining encoded information over time.
  • Retrieval – Accessing stored information when needed.

Memory Stores (Three Main Stores)

  • Sensory Memory
    • Type of Info: Raw sensory input (visual, auditory, tactile)
    • Duration: 0.2\text{ s} \;-\; 4\text{ s}
    • Capacity: Very large but brief
  • Short-Term Memory (STM)
    • Type of Info: Current thoughts / working information
    • Duration: 18-30\text{ s} (without rehearsal)
    • Capacity: 7 \pm 2 items
  • Long-Term Memory (LTM)
    • Type of Info: Permanent knowledge & experiences
    • Duration: Potentially lifelong
    • Capacity: Unlimited

Information Processing Model (Flow)

1) Sensory Input → Sensory Memory (attention needed to move on)
2) Attention → Short-Term Memory (STM holds current info)
3) Encoding → Long-Term Memory (via rehearsal & processing)
4) Retrieval → Back to STM when needed

  • Key Steps:
    • Attention: Focus on information to move it into STM.
    • Rehearsal/Processing: Deep thinking or repetition to move into LTM.
    • Retrieval Cues: Triggers to bring LTM into STM for use.

Holding Information in STM

  • Chunking – Grouping items into meaningful units.
  • Maintenance Rehearsal – Repeating information over and over.
  • Elaboration Rehearsal – Linking new information to existing knowledge for deeper encoding.

Serial Position Effect

  • Primacy Effect – Better recall for early items (LTM).
  • Recency Effect – Better recall for recent items (STM).

Types of Long-Term Memory

  • Procedural – Skills & habits (e.g., riding a bike).
  • Declarative – Facts & events
    • Semantic – General knowledge (e.g., capital of France).
    • Episodic – Personal experiences (e.g., first day of school).

Brain Regions in Memory

  • Hippocampus – Formation of new declarative memories.
  • Amygdala – Emotional memory processing.
  • Cerebellum – Procedural memories & motor skills.
  • Case of HM – Hippocampus removed → could form procedural but not new declarative memories.

Types of Retrieval

  • Recall – Producing information without cues.
  • Recognition – Identifying information from options.
  • Re-learning – Learning again; faster than first time.

Retrieval Cues

  • State-dependent – Same mood/physiological state aids recall.
  • Context-dependent – Same environment aids recall.

Semantic Networks

  • Memory is organized in interconnected nodes (concepts linked by meaning).
  • Example: “Dog” linked to “pet,” “barks,” “fur,” etc.

Key Experiments

  • Ebbinghaus – Forgetting curve: rapid initial loss, then levels off.
  • Bartlett – Schema theory: memories reconstructed to fit existing beliefs.

Why False Memories Occur

  • Misleading information, suggestion, schema-driven distortions, imagination inflation.

Reasons for Forgetting

  • Biological – Brain injury, illness, drugs, aging.
  • Psychological – Motivated forgetting (repression).

Encoding & Retrieval Failure

  • Encoding failure – Never stored properly.
  • Retrieval failure – Stored, but cues are missing.

Theories of Forgetting

  • Natural Decay – Memory fades if unused.
  • Proactive interference – Old information interferes with new learning.
  • Retroactive interference – New information interferes with old learning.
  • Consolidation Theory – Memory needs time & sleep to stabilise.

Levels of Processing Theory

  • Deeper (semantic) processing → better retention than shallow (surface-level) processing.

Memory Enhancement Techniques

  • Self-Referential Effect – Relate information to yourself.
  • Spaced Learning/Repetition – Study in intervals.
  • Method of Loci – Use a familiar location to place mental “items.”
  • Narrative Chaining – Make a story linking items.
  • Elaboration – Add detail & associations.
  • Mnemonics – Peg-words, rhymes, acronyms, acrostics.