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Psychology
How Memory Works
Sensory, Working, and Long-Term Memory
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Memory is the brain’s system for taking in information, holding it, and using it later. It matters because learning, decision making, identity, and problem solving all depend on remembering past experiences and knowledge. Psychologists often describe memory as a flow from sensory memory to short-term or working memory to long-term memory. Each stage has different limits, time spans, and ways of being strengthened.
Key Facts
- Memory has three major processes: encoding, storage, and retrieval.
- Sensory memory holds raw input very briefly, often less than 1 second for vision and a few seconds for sound.
- Working memory can usually hold about 4 to 7 meaningful chunks at one time.
- Long-term memory can last from minutes to a lifetime and includes facts, skills, and personal experiences.
- The hippocampus is important for forming new episodic memories, especially memories of events and places.
- Spaced repetition improves recall because reviewing after increasing time gaps strengthens retrieval pathways.
Vocabulary
- Sensory memory
- Sensory memory is the brief storage of sights, sounds, and other sensory information before attention selects what to process further.
- Working memory
- Working memory is the limited mental workspace used to hold and manipulate information for a short time.
- Long-term memory
- Long-term memory is the storage system that keeps information, skills, and experiences for extended periods.
- Hippocampus
- The hippocampus is a brain structure that helps encode and organize new episodic memories.
- Retrieval
- Retrieval is the process of accessing stored information when it is needed.
Common Mistakes to Avoid
- Treating memory like a video recording, which is wrong because memories are reconstructed and can be changed by attention, emotion, and later information.
- Trying to memorize everything in one long session, which is wrong because massed practice often produces weaker long-term recall than spaced repetition.
- Confusing working memory with long-term memory, which is wrong because working memory is temporary and limited while long-term memory can store large amounts of information.
- Rereading notes without testing yourself, which is wrong because retrieval practice strengthens recall more effectively than simple exposure.
Practice Questions
- 1 A student can hold 6 chunks in working memory. If a 12-digit password is grouped into chunks of 3 digits, how many chunks are there, and is it likely to fit in working memory?
- 2 You review vocabulary on day 1, day 2, day 5, and day 12. How many days are between each review session, and why might this spacing help memory?
- 3 Song lyrics often stick better than random passwords. Explain how rhythm, emotion, repetition, and meaningful chunks can improve encoding and retrieval.