Memory

Chapter 6 Memory

Memory Definition

  • Memory: An active system that processes information by receiving it from the senses, organizing, altering it during storage, and retrieving it from storage when needed.

Key Processes in Memory

  • Encoding: Mental operations performed on sensory information to convert it into usable forms for storage in the brain.

  • Storage: Holding information for varying lengths of time.

  • Retrieval: Accessing stored information and bringing it into a usable format.

Information-Processing Model: Three Stages of Memory

  • Model Assumption: Memory processing is analogous to a computer's memory processing in three stages.

Sensory Memory

  • Definition: The initial stage where information enters the nervous system via senses.

  • Duration: Information is held briefly (about a second or less).

  • Encoding: Information is encoded as neural messages while traveling through the system.

  • Perception: Occurs if the information is attended to and encoded into meaningful patterns.

Short-term Memory (STM) / Working Memory

  • Definition: The memory system for holding information briefly while using it.

  • Duration: Holds information for about 18 seconds.

  • Capacity: Limited to about 7 items (plus or minus 2).

  • Chunking: Grouping items into smaller chunks enhances storage capacity.

  • Processes: Maintenance (holding information) and manipulation (working on that information).

Long-term Memory (LTM)

  • Definition: Memory system for information that can be stored more or less permanently.

  • Capacity: Potentially unlimited, though unknown.

  • Types of Long-term Memory:

    • Procedural Memory: Skills, habits, and conditioned responses.

    • Declarative Memory: Knowledge and facts.

      • Semantic Memory: Generalized knowledge and language.

      • Episodic Memory: Personal events and specific experiences.

Retrieval of Long-Term Memories

  • Encoding Specificity: Memory retrieval is improved when related information present at encoding is also available at retrieval.

    • Examples: Surroundings, physiological states.

  • State-Dependent Memory: Retrieval is easier when in a similar physiological or psychological state as when the memory was formed.

  • Types of Retrieval:

    • Recall: Pulling information from memory with few external cues.

    • Recognition: Matching information or stimulus to a stored memory/image.

Forgetting

  • Reasons for Forgetting:

    • Encoding Failure: Inability to process information into memory.

    • Decay: Loss of memory over time due to disuse.

  • Interference Theory: New or old information interferes with memory processes.

    • Proactive Interference: Older information inhibits retrieval of newer information.

    • Retroactive Interference: Newer information inhibits retrieval of older information.

  • Amnesia: Severe memory loss due to brain dysfunction.

    • Retrograde Amnesia: Loss of memories prior to injury; often recovers from oldest to newest memories.

    • Anterograde Amnesia: Loss of ability to form new episodic memories post-injury; can still develop implicit procedural memories.