Human memory is broadly divided into two main categories: short-term memory (also known as working memory) and long-term memory. These categories can be further subdivided, offering a more nuanced understanding of how we store and retrieve information.
Short-Term Memory (Working Memory)
Short-term memory is a temporary storage system that holds a limited amount of information for a brief period. It's like the "scratchpad" of the mind, actively processing information needed for immediate tasks. Key characteristics include:
- Limited Capacity: Can typically hold around 7 +/- 2 items (e.g., digits, words).
- Short Duration: Information is retained for a matter of seconds without active maintenance.
- Active Processing: Involves manipulating information rather than just passively storing it.
- Example: Remembering a phone number long enough to dial it.
Long-Term Memory
Long-term memory is a vast and relatively permanent storage system capable of holding an almost unlimited amount of information for a long time – even a lifetime. It's often divided into two major subtypes: declarative (explicit) memory and nondeclarative (implicit) memory.
Declarative (Explicit) Memory
Declarative memory involves conscious recollection of facts and events. It's "knowing that." This type of memory is accessible to conscious awareness and can be explicitly stated. It can be further divided into:
- Episodic Memory: Memory for specific events or experiences, tagged with a time and place.
- Example: Remembering your high school graduation.
- Semantic Memory: Memory for general knowledge, facts, and concepts.
- Example: Knowing that Paris is the capital of France.
Nondeclarative (Implicit) Memory
Nondeclarative memory involves unconscious or implicit learning and memory. It's "knowing how." This type of memory is expressed through performance rather than conscious recall. It includes:
- Procedural Memory: Memory for skills and habits.
- Example: Riding a bike or playing the piano.
- Priming: Enhanced identification of objects or words as a result of prior exposure.
- Example: Being able to complete the word fragment "a_p_e" as "apple" faster after being shown a picture of an apple.
- Classical Conditioning: Learning through association.
- Example: Salivating at the sound of a bell that has been repeatedly paired with food.
- Nonassociative Learning: Habituation and sensitization.
Summary
In summary, human memory is organized into short-term (working) and long-term memory systems. Long-term memory is further divided into declarative (explicit) and nondeclarative (implicit) forms, each with its own subtypes and functions.
