Working and long-term memory, forgetting

Long-term memory (LTM)

Long-term memory is essentially limitless in storage capacity and retains information that happened more than a few minutes ago. Its organization follows a system of semantic (associative) networks, where concepts (categories of language, ideas, or experiences) are interconnected. When a certain concept in a semantic network is triggered, related ideas also receive a partial boost in activation, a process called spreading activation. As a result, recalling associated concepts becomes easier because they are already primed. Moreover, these activations spread in multiple directions, meaning you can take several “routes” to reach the information you need. The more connections a concept has, the higher the likelihood of retrieving it.

Types of long-term memory

Explicit (declarative) memory:
- Conscious effort: Requires active recall or recognition.
- Example: Studying for an exam.
Implicit memory:
- Unconscious influence: Involves processes we can’t easily articulate but which affect our actions.
- Procedural memory: Skills like riding a bike or driving a car.
- Priming: Exposure to a stimulus influences a later response, such as a red hexagon priming the concept of “stop.”
Episodic memory:
- Events or experiences: Recollections of significant or meaningful occurrences, such as the details of a natural disaster.
Semantic memory:
- Factual knowledge: Knowing the names of capital cities or historical facts.
Autobiographical memory:
- Personal life history: Includes details about relationships, personal milestones, and emotions.
Retrospective memory:
- Recalling past information: Integrates episodic, semantic, declarative, and autobiographical memories.
Prospective memory:
- Future-oriented tasks: Remembering to perform actions later, such as picking up the dry cleaning.

Retrieval

Retrieval is bringing information back to conscious awareness. It takes several forms:

Recall

Accessing information without external cues (e.g., essay questions).
- Serial recall: Remembering in the sequence events happened.
- Free recall: Spontaneously recalling items with no prompts.
- Cued recall: Triggered by prompts or hints.
- Recognition: Identifying previously learned information after seeing it again, as with multiple-choice tests.
- Relearning: Refreshing or restoring previously acquired knowledge that has faded over time.

Retrieval cues

Retrieval cues prompt us to recall memories. These can be external (e.g., a scent) or internal (e.g., an emotion). Intentional cues, like notes or margin keywords, help commit information to memory. When retrieval cues are insufficient or too weak, retrieval failure may occur, leading to forgetting.

Forgetting and aging

Short-term decline: Around age sixty, neuron loss can reduce short-term memory capacity.
Recall vs. recognition: Older adults may find free recall more difficult, though recognition often remains relatively intact.
Meaningful information: People more easily retain personally significant data, while less important details are more easily lost.