Short and long term memory

The idea

Short-term memory (STM) is a limited-capacity, limited-duration store that holds information currently being attended to, whereas long-term memory (LTM) is a potentially unlimited store holding information for long periods. In the general information processing model, sensory input enters STM, where it can be maintained by rehearsal; rehearsal and meaningful encoding transfer information into LTM, and retrieval brings it back into STM for use. For example, a gymnast rehearses a vault sequence in STM before it becomes an automatic LTM routine. Capacity and duration differ: STM holds a small number of items briefly, while LTM can retain vast amounts of motor and declarative knowledge. Understanding this distinction helps explain why skills need repeated practice to become permanent.

What earns the marks

• STM has limited capacity and limited duration, whereas LTM has potentially unlimited capacity and long duration.
• Information enters STM from sensory input and can be maintained by rehearsal.
• Rehearsal and encoding transfer information from STM into LTM.
• Retrieval brings stored information from LTM back into STM for use in performance.
• In physical activity, repeated practice moves a skill from conscious STM control towards automatic LTM storage.

Common mistakes and how to put them right

• Misunderstanding: STM and LTM are the same store with different names.

  Put it right: They are separate stores with different capacity and duration.

• Misunderstanding: information passes directly from the environment into LTM.

  Put it right: Sensory input first enters STM, and rehearsal or encoding is needed for transfer to LTM.

• Misunderstanding: LTM is only for facts and never for movement skills.

  Put it right: LTM stores motor programmes and procedural skills as well as declarative knowledge.

• Misunderstanding: rehearsal is only repeating words silently.

  Put it right: Rehearsal can be physical practice or mental rehearsal that strengthens the memory trace.

Exam tips

• Read the question carefully to identify whether it asks about capacity, duration, transfer or retrieval before choosing an option.
• Eliminate options that describe LTM as limited or STM as permanent, because these reverse the key features.
• Link each option to a sporting example, such as a tennis serve becoming automatic after many repetitions, to check it makes sense.