Understanding the differences between the stores is essential for identifying where a memory failure occurs.
| Feature | Sensory Register | Short-Term Memory | Long-Term Memory |
|---|---|---|---|
| Coding | Modality-specific | Acoustic | Semantic |
| Capacity | Very High | items | Unlimited |
| Duration | < 1 second | 18–30 seconds | Lifetime |
| Loss Cause | Decay | Displacement/Decay | Interference/Retrieval Failure |
Identify the Store: When presented with a scenario, first determine which store is being tested by looking for clues about duration (seconds vs. years) or capacity (number of items).
Use Research Evidence: Support your answers with key findings, such as Baddeley's work on coding (acoustic vs. semantic) or Miller's 'Magic Number 7' for STM capacity.
Evaluate the Model: Be prepared to discuss strengths (e.g., clear structure, research support) and limitations (e.g., over-simplification of STM, artificiality of lab tasks).
Check for Rehearsal: If a scenario mentions a person repeating a phone number, they are using maintenance rehearsal to extend STM duration.
Rehearsal is not just repetition: Students often forget that simple repetition (maintenance) only keeps info in STM; deeper processing (elaborative) is usually required for LTM.
Capacity vs. Duration: Do not confuse how much can be held (capacity) with how long it can be held (duration).
LTM is not 'perfect': While LTM has unlimited capacity, memories can still be 'lost' due to retrieval failure, even if the data technically exists in the store.