Memory

AP Psychology Notes — Memory

I. What Memory Is

• Memory: the capacity to encode (acquire), store (retain), and retrieve information.

• Functions:

  • Apply past knowledge to new situations

  • Solve problems

  • Plan for the future

  • Maintain personal identity and continuity

II. Information-Processing Model

• Compares the brain to a computer.

• Information flows through three stages:

  1. Acquisition (Encoding) – transforming information into a storable form.

  2. Retention (Storage) – maintaining information over time.

  3. Retrieval – accessing stored information.

III. Levels of Processing Theory

• Memory depends on depth of processing, not repetition alone.

• Shallow processing: sensory features (sound, appearance).

• Deep processing: meaning, associations, connections to prior knowledge.

• Deeper processing → stronger, longer-lasting memories.

• Uses semantic networks (linked concepts in long-term memory).

IV. Memory Systems (Atkinson–Shiffrin Model)

1. Sensory Memory

• Very brief storage of raw sensory input.

• Iconic (visual): ~0.25 seconds.

• Echoic (auditory): ~3 seconds.

• Purpose: prevents perception from seeming discontinuous.

2. Short-Term Memory (STM) / Working Memory

• Holds information currently in use.

• Capacity: 7 ± 2 items (George Miller).

• Duration: < 30 seconds without rehearsal.

• Displacement: new information pushes old information out.

3. Long-Term Memory (LTM)

• Virtually unlimited capacity and duration.

• Divided into:

  • Declarative (explicit)

  • Procedural (implicit)

V. Types of Long-Term Memory

Declarative (Explicit) Memory

• Conscious recall of facts and events.

• Episodic: personal experiences (first day of school).

• Semantic: facts and meanings (definitions, vocabulary).

Procedural (Implicit) Memory

• Skills and habits.

• No conscious recall required.

• Examples: riding a bike, typing, swimming.

VI. Special Memory Phenomena

• Flashbulb memory: vivid memory of emotionally charged events.

• Eidetic (photographic) memory: rare ability to retain images briefly with extreme detail.

• Priming: prior exposure increases likelihood of recall or response later.

VII. Measuring Memory

1. Recall – retrieve information without cues.

2. Recognition – identify correct information from options.

3. Reconstruction – rebuild memory from fragments (error-prone).

Confabulation

• Filling memory gaps with plausible but false details.

• Happens during reconstruction.

VIII. Biological Basis of Memory

H.M. Case Study

• Removal of hippocampus → anterograde amnesia.

• Could not form new memories.

• Showed hippocampus is crucial for memory formation, not storage.

Long-Term Potentiation (LTP)

• Strengthening of synaptic connections.

• Neural basis of long-term memory.

• Requires protein synthesis.

• Repetition strengthens neural pathways.

Trauma and Memory

• Recent memories are vulnerable before consolidation.

• Blows to the head or electroshock disrupt recent but not old memories.

IX. Emotion, Hormones, and Memory

• Emotional arousal → adrenal glands release adrenaline & noradrenaline.

• These hormones signal the brain to prioritize memory formation.

• Amygdala plays key role in emotional memories.

• Explains durability of flashbulb memories.

X. Own-Group Bias (Own-Race / Own-Gender Bias)

Definition

• Tendency to recognize faces of one’s own group more accurately than others.

Why It Happens

• Contact hypothesis: more exposure to similar faces.

• Deeper processing of familiar-looking faces.

• Evolutionary attention to social competitors (same gender).

Key Findings

• People remember faces of their own race and gender better.

• Hair is a major cue in quick face recognition.

• Accuracy drops when hair is hidden.

• Bias strongest across racial groups.

Importance

• Eyewitness memory is confident but unreliable.

• Major factor in wrongful convictions.

• Courts may allow expert testimony on this bias.

Core Idea