General Knowledge

General Knowledge

LTM Types (Categorization)

• Semantic LTM: Generalized, fact-based knowledge.

• Episodic LTM: Memory of events occurring at specific times and locations.

• Procedural LTM: Knowledge of how to perform tasks or functions.

• Note: Overlap is common in LTM types, rather than clear distinctions.

Background and Approaches to Semantic Memory

What is Semantic Memory?

• Refers to our general world knowledge: concepts, facts, meanings, and categories.

• Example: Knowing that a dog is a mammal or that Paris is the capital of France.

• Distinction: Unlike episodic memory, semantic memory is decontextualized and independent of the time and place of acquisition.

Importance

• Classifies objects, understands language, makes inferences, and navigates the world.

• Underpins reasoning, categorization, and problem-solving.

The Feature Comparison Approach

Definition

• Concepts stored in memory as lists of features or characteristics.

• Object recognition involves comparing presented stimuli to this set of features.

Features

• Defining Features: Necessary for an item's meaning.

• Characteristic Features: Descriptive but not essential.

Limitations

• No objective method to determine defining vs. characteristic features.

• Fails to explain relationships among category members (even with shared features).

Prototype Approach

Definition

• Categories organized around prototypes—idealized or average examples.

• Prototypes may not exist in reality but capture core common features.

Key Features

• Prototypicality: Some members are better examples of a category (e.g., robin vs. penguin).

• Graded Membership: Continuum from typical to atypical examples.

• Family Resemblance: Items share overlapping features; no single feature is necessary.

Evidence

• Typicality Effect: Faster categorization and recall for typical items (e.g., recalling apple faster than kiwi).

Exemplar Approach

Definition

• Categorization involves comparing new objects to stored exemplars (numerous specific examples of category members).

• Effective for smaller or less familiar categories (e.g., types of ancient coins).

Key Features

• Influences of unusual examples, not just averages.

• Early learning stages involve remembering individual examples before forming general concepts.

Evidence

• Supports variability within categories.

Comparing the Prototype and Exemplar Approaches

Current View

• Both approaches are not mutually exclusive; usage depends on:

  • Category size

  • Familiarity

  • Specificity of task

Comparison

Schemas and Scripts

Schemas

• Generalized mental frameworks representing knowledge about a situation, event, or concept.

• Example: Restaurant schema (menus, ordering, paying).

Scripts

• Specific schema focusing on expected sequences of actions in routine activities.

• Example: "Going to a restaurant" script includes:

  • Being seated

  • Ordering food

  • Eating

  • Paying

  • Leaving

Functions

• Guide encoding and retrieval.

• Help fill in missing information (reconstruction).

• Allow quick interpretation of new situations.

Memory Selection (Role of Schemas)

• Schemas influence attention and memory encoding.

• Schema-consistent information is more likely to be remembered (top-down processing).

• Schema-inconsistent but salient information (e.g., a kangaroo in a classroom) can also be memorable.

• Example: Participants in an office remember books (schema-consistent) even if absent, yet can remember a skull (schema-inconsistent).

Boundary Extension

Definition

• Boundary Extension: Tendency to remember more of a scene than was actually present.

• Example: After viewing a close-up of a table, participants recall parts of the room not shown.

Explanation

• Established schemas for spatial layouts fill in unseen edges.

• A form of schema-driven memory reconstruction.

Memory Abstraction

Definition

• Storing the gist (general meaning) rather than exact details.

• Particularly pronounced in semantic memory.

Example

• People remember general themes better than word-for-word text after reading a story.

Theories

• Constructive Approach: Memory as an active construction influenced by prior knowledge.

• Pragmatic Approach: Memory focuses on what is useful or emotionally salient, not every detail.

Memory Integration

Definition

• Memory Integration: Combining information from various sources into a coherent whole.

• Blending new information with existing knowledge (schemas) forms a unified memory trace.

Examples

• In learning historical events, students integrate textbook content, lectures, and prior beliefs into cohesive memories.

• In recalling conversations, remembered content may involve inferences based on the person’s personality.

Risk

• Can cause memory distortions, including false memories, when schema-based assumptions are incorrectly remembered as actual events.