long term memory

Meaning: Long-term memory is the last stage of the information-processing model: sensory memory → short-term (working) memory → long-term memory. Its capacity is very large, and memories can last for years. Explicit (declarative) memory is consciously recalled and includes episodic memory (personal events) and semantic memory (facts). Implicit (nondeclarative) memory shows up in performance and includes procedural skills, priming and classical conditioning. The hippocampus is needed to form new explicit memories, while the cerebellum and basal ganglia support procedural learning. At the cellular level, long-term potentiation strengthens synapses.

On the MCAT: Expect a patient with hippocampal damage who cannot form new explicit memories (anterograde amnesia) yet improves at a motor task. In serial position experiments, the primacy effect reflects long-term storage and the recency effect reflects short-term storage, so a delay with distraction weakens recency. Deep, meaningful encoding and elaborative rehearsal beat maintenance rehearsal. Retrieval is tested by recall, recognition and relearning.

Common confusion: Long-term does not mean permanent or accurate. Forgetting can come from decay, interference or retrieval failure, and recalled memories can be reconstructed. Also, a skill like riding a bike is long-term but implicit, not explicit.