memory

memory

1. msm

   • The Multi-Store Model (MSM) was proposed by Atkinson & Shiffrin (1968). It explains memory as three separate stores through which information passes in a linear process:
     • Sensory Register → Short-Term Memory (STM) → Long-Term Memory (LTM)
       • Key Processes in MSM
         • Process Description Attention Focus on sensory input → moves to STM Rehearsal Repeating information → maintains STM; elaborative rehearsal → transfers to LTM Retrieval Accessing information from LTM back to STM
           • Strengths of MSM
             • Empirical support: Lab studies support separate stores (e.g., Peterson & Peterson; Baddeley). Simplicity: Provides clear stages and processes. Practical application: Helps understand memory disorders (e.g., amnesia).
           • Limitations of MSM
             • Oversimplified: Assumes STM and LTM are single, uniform stores. Ignores other types of LTM: Episodic, semantic, procedural not distinguished. Evidence from case studies: HM and KF suggest STM is more complex (e.g., different stores for auditory vs. visual info). Rehearsal isn’t always necessary for LTM (e.g., flashbulb memories).
   • sensory register
     • Function: Receives information from the environment via the senses. Duration: Very brief (<0.5–2 seconds depending on the sense) Capacity: Very large (all sensory input, but only a fraction is attended to) Coding: Modality-specific (e.g., visual = iconic, auditory = echoic) Key Study: Sperling (1960) – Partial report technique showed iconic memory holds large amounts briefly. Transfer to STM: Requires attention.
   • Short-Term Memory (STM)
     • Function: Holds information currently being used or attended to. Duration: ~18–30 seconds (without rehearsal) Capacity: 7 ± 2 items (Miller, 1956) Coding: Mainly acoustic Maintenance: Rehearsal (repetition) is key for retention. Transfer to LTM: Requires elaborative rehearsal (linking information meaningfully) Displacement: New information can push out old info if capacity is exceeded. Evidence: Peterson & Peterson (1959) – duration of STM tested using trigram recall with varying intervals.
   • Long-Term Memory (LTM)
     • Function: Stores information indefinitely. Duration: Potentially lifelong Capacity: Essentially unlimited Coding: Mainly semantic (by meaning) Retrieval: Information moves back to STM via retrieval Supporting Evidence: Bahrick et al. (1975) – very long-term recall of high school classmates.

2. WMM

   • The Working Memory Model (WMM) was proposed by Baddeley & Hitch (1974) as a more detailed alternative to the STM component of the MSM. It suggests that STM is not a single store but a multi-component system for temporary storage and manipulation of information.
     • Key Features
       • Active system: Holds and manipulates information, not just stores it. Modality-specific: Different subsystems for different types of info (PL = verbal, VSS = visual). Limited capacity: Each subsystem can hold only so much information. Supports dual-task studies: Shows how different components can work independently.
   • Components of the WMM
     • Central Executive (CE)
       • Directs attention and coordinates the other subsystems. Allocates mental resources depending on the task. Very limited capacity. Modality-free (can handle any type of information). Evidence: Dual-task studies (Baddeley & Hitch, 1976) – participants could do verbal and visual tasks simultaneously, showing separate components are managed by CE.
     • Phonological Loop (PL)
       • Processes verbal and auditory information. Limited to about 2 seconds of speech or ~7 items. Deals with language, sounds, and speech-based memory. Evidence: Word-length effect (Baddeley, 1975) – harder to remember long words than short words.
     • Visuo-Spatial Sketchpad (VSS)
       • Stores visual and spatial information. Limited to about 3-4 objects at a time. Handles visual patterns, images, and spatial awareness. Evidence: Brooks (1968) – visual and verbal tasks interfere only when they share the same subsystem.
     • Episodic Buffer (EB) (added 2000 by Baddeley)
       • Integrates information from CE, PL, VSS, and long-term memory (LTM). Creates coherent “episodes” of memory. Limited capacity of around 4 chunks. Evidence: Explains how we can combine visual, verbal, and long-term memory info in one task.
   • Strengths
     • Explains dual-task performance better than the Multi-Store Model. Supported by strong experimental evidence (PL, VSS studies). Accounts for manipulation of information, not just storage.
   • Weaknesses
     • Central Executive is vague and hard to measure directly. Less clear on interactions with long-term memory. VSS may be more complex than a single subsystem.

3. Explanations for Forgetting

   • Forgetting is the inability to recall or retrieve information that was previously stored. Psychologists explain forgetting using two main approaches: interference and retrieval failure.
   • Interference Theory
     • Forgetting occurs because one memory blocks another, causing confusion. Works best for similar types of information.
     • Proactive Interference (PI)
       • Older memories interfere with new ones. Example: You keep typing your old password instead of your new one.
     • Retroactive Interference (RI)
       • New memories interfere with older ones. Example: Learning a new phone number makes you forget your old one.
     • Evidence:
       • McGeoch & McDonald (1931): Participants learned a list of words, then a second list. Forgetting was greatest when the second list was similar to the first. Shows interference is strongest when memories overlap or are similar.
     • Evaluation:
       • ✅ Lab studies show consistent effects. ❌ Artificial tasks (lists of words) may not reflect real-life forgetting. ❌ Doesn’t explain forgetting of unique, meaningful memories.
   • Retrieval Failure Theory (Cues)
     • Forgetting occurs when cues are absent. The memory is available but not accessible. Key idea: Memory retrieval depends on having the right cues present.
     • Context-dependent forgetting
       • External environment acts as a cue. Example: Godden & Baddeley (1975) – Divers recalled words better in the same environment they learned them (land vs water).
     • State-dependent forgetting
       • Internal state (mood, drugs) acts as a cue. Example: Goodwin et al. (1969) – Participants who were drunk when learning remembered less if sober at recall
     • Evaluation:
       • ✅ Strong evidence from lab and field studies. ✅ Explains everyday forgetting well. ❌ Some studies have failed to replicate cue effects in real-life settings.

4. EYE WITNESS TESTIMONY (EWT) & FACTORS AFFECTING ACCURACY

   • EWT is an account given by a person of an event they have witnessed. Memory for events can be highly accurate or distorted, making EWT an important topic in forensic psychology.
   • Memory is reconstructive – people often fill gaps with assumptions or expectations. Accuracy can be influenced by internal and external factors.
   • FACTORS AFFECTING EWT ACCURACY
     • Misleading Information
       • Definition: Information presented after an event can distort a witness’s memory. Types: Leading questions – questions that suggest an answer. Study: Loftus & Palmer (1974) – Participants asked how fast cars were “smashed” vs “hit.” Higher speed estimates and false memory of broken glass for “smashed.” Post-event discussion – discussing events with others can alter memories. ⭐ Star Evaluation: ✅ Strong lab evidence for leading questions altering memory. ✅ Explains real-life courtroom errors. ❌ Lab studies use artificial tasks (videos vs real crime), limiting ecological validity. ⭐ Advanced: Memory conformity – witnesses may incorporate others’ memories into their own.
     • Anxiety / Stress
       • Definition: High arousal or stress at the time of a crime can affect recall accuracy. Effects: Negative effect: High stress can narrow attention, reducing memory for peripheral details. Study: Yuille & Cutshall (1986) – Real-life shooting; witnesses with highest stress recalled details more accurately – shows sometimes stress improves memory (flashbulb effect). Weapon focus effect: Presence of a weapon draws attention to it, reducing memory for other details. Study: Johnson & Scott (1976) – Witnesses focused on a bloody knife rather than the perpetrator’s face. ⭐ Star Evaluation: ✅ Supported by real-life and lab evidence. ✅ Shows stress is not always negative (inverted-U hypothesis). ❌ Ethical constraints make it hard to test extreme stress experimentally. ⭐ Advanced: Yerkes-Dodson law – moderate stress can improve memory; very high stress impairs it.
     • Cognitive Interview (CI)
       • Definition: Technique to improve accuracy and quantity of EWT. Techniques: Report everything – even minor details. Reinstate context – mentally recreate the environment. Reverse order – recall events in different sequences. Change perspective – imagine the event from another viewpoint. Evidence: Geiselman et al. (1985): CI increased correct recall in lab settings compared to standard interviews. ⭐ Star Evaluation: ✅ Increases quantity and accuracy of recall. ✅ Supported in real-life police work. ❌ More time-consuming than standard police interviews. ⭐ Advanced: Enhanced Cognitive Interview (ECI) – includes social rapport and open-ended questions, further improving accuracy.
     • Other Factors
       • Age: Children and older adults may be more susceptible to suggestion. Time delay: Longer delays between event and recall increase forgetting and distortion. Individual differences: Intelligence, stress resilience, and eyewitness training affect memory accuracy.