📚 Memory Models

Multi-Store Model of Memory (Atkinson & Shiffrin, 1968)

Sensory Register: Very brief storage (0.5s). High capacity. Iconic (visual) & echoic (auditory) memory.
Short-Term Memory (STM): Limited capacity (7±2 items, Miller). Duration 18-30s. Acoustic encoding. Maintenance rehearsal keeps info in STM.
Long-Term Memory (LTM): Unlimited capacity. Lifetime duration. Mainly semantic encoding. Retrieval brings info back to STM.

Working Memory Model (Baddeley & Hitch, 1974)

Central Executive: Controls attention, coordinates slave systems. Limited capacity. Modality-free.
Phonological Loop: Processes auditory information. Phonological store (inner ear) + articulatory process (inner voice).
Visuo-Spatial Sketchpad: Processes visual/spatial information. Visual cache (stores) + inner scribe (arranges).
Episodic Buffer: (Added 2000) Integrates information from different sources and links to LTM. Limited capacity.

Types of Long-Term Memory (Tulving, 1985)

Episodic Memory: Personal experiences/events (when, where, who, what). Time-stamped. Conscious recall ("mental time travel").
Semantic Memory: Facts and knowledge. Not time-stamped. Less personal. Conscious recall.
Procedural Memory: Skills and actions (e.g., riding bike). Unconscious. Automatic.

🔬 Key Studies on Memory

Peterson & Peterson (1959) - STM Duration

Aim: To investigate the duration of short-term memory
Procedure: 24 students. Shown consonant trigrams (e.g., TGH). Retention intervals of 3, 6, 9, 12, 15, 18 seconds. Counted backwards in 3s during interval to prevent rehearsal.
Findings: 90% recall after 3s. 20% after 9s. 2% after 18s.
Conclusion: STM duration is very brief (18-30 seconds) without rehearsal

Jacobs (1887) - STM Capacity (Digit Span)

Aim: To investigate the capacity of short-term memory
Procedure: Participants heard sequences of digits/letters. Had to repeat them back in correct order. Sequence length increased until unable to recall correctly.
Findings: Mean digit span: 9.3 items. Mean letter span: 7.3 items.
Conclusion: STM has limited capacity (7±2 items) - Miller later confirmed this

Baddeley (1966) - Encoding in STM/LTM

Aim: To investigate encoding in short-term and long-term memory
Procedure: Four groups shown word lists: acoustically similar (cat, cab, can), acoustically dissimilar, semantically similar (great, large, big), semantically dissimilar. Recalled immediately (STM) or after 20 minutes (LTM).
Findings: STM: worse recall for acoustically similar words. LTM: worse recall for semantically similar words.
Conclusion: STM encodes acoustically (sound). LTM encodes semantically (meaning).

Bahrick et al. (1975) - LTM Duration

Aim: To investigate very long-term memories (VLTMs) in a real-life setting
Procedure: 392 American participants (17-74 years). Tested on memory of high school classmates. Photo recognition test and free recall test.
Findings: Photo recognition: 90% accurate after 15 years, 70% after 48 years. Free recall: 60% after 15 years, 30% after 48 years.
Conclusion: LTM can last a lifetime. Recognition better than recall.

Tulving & Pearlstone (1966) - Retrieval Cues

Aim: To investigate whether cues help retrieval from LTM
Procedure: Participants learned 48 words from 12 categories. Free recall vs. cued recall (given category names).
Findings: Free recall: 40% recalled. Cued recall: 60% recalled.
Conclusion: Information is in LTM but not always accessible. Cues improve retrieval.

🧩 Explanations for Forgetting

Interference Theory

Proactive Interference (PI): Old memories interfere with new ones (e.g., calling new partner by ex's name)
Retroactive Interference (RI): New memories interfere with old ones (e.g., new phone number makes you forget old one)
Most likely when memories are similar

Retrieval Failure (Encoding Specificity Principle)

Memory is most effective when context/cues at encoding match those at retrieval
Context-Dependent Forgetting: External environment cues (e.g., location)
State-Dependent Forgetting: Internal physiological/psychological cues (e.g., mood, drugs)

👁️ Eyewitness Testimony (EWT)

Misleading Information - Leading Questions

Questions phrased in a way that suggests a certain answer
Response Bias: Wording influences answer but doesn't change memory
Substitution: Wording actually alters memory (Loftus)

Misleading Information - Post-Event Discussion

Witnesses discussing events can contaminate each other's memories
Memory Contamination: Co-witnesses mix information from others into their own memory
Memory Conformity: Witnesses go along with others for social approval

Anxiety Effects on EWT

Yerkes-Dodson Law: Inverted-U relationship. Moderate anxiety improves accuracy, very high/low anxiety impairs it.
Weapon Focus Effect: Anxiety about weapon reduces accuracy for other details

Cognitive Interview (Fisher & Geiselman, 1992)

Report Everything: Include all details, even seemingly trivial
Reinstate Context: Mentally recreate environment and emotions
Reverse Order: Recall events in different chronological order
Change Perspective: Recall from different viewpoints
Enhanced CI: + rapport building, minimize distractions, open questions, witness controls flow