Memory Tiers Architecture¶

This diagram provides a detailed view of the NeuroCognitive Architecture (NCA) memory tier system, focusing on the interaction between the three memory tiers.

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graph TB
    classDef main fill:#1a1a1a,stroke:#555,color:#fff
    classDef component fill:#242424,stroke:#555,color:#fff
    classDef subcomponent fill:#2b2b2b,stroke:#555,color:#fff
    classDef working fill:#203040,stroke:#555,color:#fff
    classDef episodic fill:#303020,stroke:#555,color:#fff
    classDef semantic fill:#302030,stroke:#555,color:#fff
    classDef interface fill:#203030,stroke:#555,color:#fff

    subgraph TierSystem["Memory Tier System"]
        direction TB
        class TierSystem main

        subgraph Interfaces["Memory Interfaces"]
            direction TB
            class Interfaces interface
            API[Memory API] --- Config[Memory Config]
            Events[Memory Events] --- Metrics[Memory Metrics]
            class API,Config,Events,Metrics subcomponent
        end

        subgraph WorkingMem["Working Memory (STM)"]
            direction TB
            class WorkingMem working

            subgraph STMCore["Working Memory Core"]
                direction TB
                class STMCore working
                Buffer[Memory<br>Buffer] --- Attention[Attention<br>Focus]
                Chunking[Memory<br>Chunking] --- Rehearsal[Active<br>Rehearsal]
                class Buffer,Attention,Chunking,Rehearsal subcomponent
            end

            subgraph STMProcessing["Working Memory Processing"]
                direction TB
                class STMProcessing working
                Encoding[STM<br>Encoding] --- Retrieval[STM<br>Retrieval]
                DecayMech[Decay<br>Mechanism] --- Displacement[Item<br>Displacement]
                class Encoding,Retrieval,DecayMech,Displacement subcomponent
            end

            subgraph STMProperties["Working Memory Properties"]
                direction TB
                class STMProperties working
                Capacity[Limited<br>Capacity] --- Duration[Short<br>Duration]
                Volatility[High<br>Volatility] --- Accessibility[Immediate<br>Access]
                class Capacity,Duration,Volatility,Accessibility subcomponent
            end
        end

        subgraph EpisodicMem["Episodic Memory (EM)"]
            direction TB
            class EpisodicMem episodic

            subgraph EMCore["Episodic Memory Core"]
                direction TB
                class EMCore episodic
                Episodes[Episode<br>Store] --- Context[Context<br>Binding]
                Temporal[Temporal<br>Sequencing] --- Spatial[Spatial<br>Information]
                class Episodes,Context,Temporal,Spatial subcomponent
            end

            subgraph EMProcessing["Episodic Memory Processing"]
                direction TB
                class EMProcessing episodic
                Encoding[EM<br>Encoding] --- Retrieval[EM<br>Retrieval]
                Consolidation[Memory<br>Consolidation] --- Reconsolidation[Memory<br>Reconsolidation]
                class Encoding,Retrieval,Consolidation,Reconsolidation subcomponent
            end

            subgraph EMProperties["Episodic Memory Properties"]
                direction TB
                class EMProperties episodic
                Capacity[Medium<br>Capacity] --- Duration[Medium<br>Duration]
                Autobiographical[Autobiographical<br>Content] --- EventBased[Event-Based<br>Structure]
                class Capacity,Duration,Autobiographical,EventBased subcomponent
            end
        end

        subgraph SemanticMem["Semantic Memory (LTM)"]
            direction TB
            class SemanticMem semantic

            subgraph LTMCore["Semantic Memory Core"]
                direction TB
                class LTMCore semantic
                Knowledge[Knowledge<br>Base] --- Concepts[Concept<br>Network]
                Facts[Factual<br>Information] --- Schemas[Schema<br>Organization]
                class Knowledge,Concepts,Facts,Schemas subcomponent
            end

            subgraph LTMProcessing["Semantic Memory Processing"]
                direction TB
                class LTMProcessing semantic
                Encoding[LTM<br>Encoding] --- Retrieval[LTM<br>Retrieval]
                Embedding[Semantic<br>Embedding] --- Association[Semantic<br>Association]
                class Encoding,Retrieval,Embedding,Association subcomponent
            end

            subgraph LTMProperties["Semantic Memory Properties"]
                direction TB
                class LTMProperties semantic
                Capacity[Large<br>Capacity] --- Duration[Long<br>Duration]
                Structure[Hierarchical<br>Structure] --- Persistence[High<br>Persistence]
                class Capacity,Duration,Structure,Persistence subcomponent
            end
        end

        subgraph TierInteractions["Memory Tier Interactions"]
            direction TB
            class TierInteractions component
            Consolidation[Memory<br>Consolidation] --- Transfer[Memory<br>Transfer]
            Promotion[Memory<br>Promotion] --- Degradation[Memory<br>Degradation]
            class Consolidation,Transfer,Promotion,Degradation subcomponent
        end

        subgraph CrossTierFunctions["Cross-Tier Functions"]
            direction TB
            class CrossTierFunctions component
            Search[Cross-Tier<br>Search] --- Recall[Assisted<br>Recall]
            Integration[Memory<br>Integration] --- Reinforcement[Memory<br>Reinforcement]
            class Search,Recall,Integration,Reinforcement subcomponent
        end
    end

    %% External connections
    MemoryManager[Memory<br>Manager] --> Interfaces
    TubuleSystem[Tubule<br>System] --> TierInteractions

    %% Internal connections
    Interfaces --> WorkingMem
    Interfaces --> EpisodicMem
    Interfaces --> SemanticMem

    %% Tier processing connections
    STMCore --> STMProcessing
    STMProcessing --> STMProperties
    EMCore --> EMProcessing
    EMProcessing --> EMProperties
    LTMCore --> LTMProcessing
    LTMProcessing --> LTMProperties

    %% Tier interaction connections
    WorkingMem --> TierInteractions
    EpisodicMem --> TierInteractions
    SemanticMem --> TierInteractions
    TierInteractions --> CrossTierFunctions

    %% Direct memory paths
    WorkingMem -- "Consolidation" --> EpisodicMem
    EpisodicMem -- "Consolidation" --> SemanticMem
    SemanticMem -- "Activation" --> EpisodicMem
    EpisodicMem -- "Retrieval" --> WorkingMem

    %% Node styling
    class MemoryManager,TubuleSystem subcomponent

Memory Tier System¶

The NCA memory system is organized into three biologically-inspired tiers that work together to provide a comprehensive memory architecture:

Working Memory (Short-Term Memory)¶

The Working Memory tier is responsible for temporarily holding information that is currently being processed:

1. Core Components:
2. Memory Buffer: Temporary storage area for active items
3. Attention Focus: Directs processing resources to specific items
4. Memory Chunking: Groups related items to increase effective capacity

5. Active Rehearsal: Maintains items through continuous activation

6. Processing:

7. Encoding/Retrieval: Fast storage and access mechanisms
8. Decay Mechanism: Automatic fading of memory items over time

9. Item Displacement: Replacement of older items when capacity is reached

10. Properties:

11. Limited Capacity: Follows Miller's Law (7±2 items)
12. Short Duration: Items persist for seconds to minutes without rehearsal
13. High Volatility: Easily disrupted by distractions
14. Immediate Access: No retrieval delay for items in working memory

Episodic Memory (Medium-Term Memory)¶

The Episodic Memory tier stores experiences and events with their associated contexts:

1. Core Components:
2. Episode Store: Storage for complete episodic memories
3. Context Binding: Attaches contextual information to episodes
4. Temporal Sequencing: Maintains chronological order of episodes

5. Spatial Information: Records spatial context of memories

6. Processing:

7. Encoding/Retrieval: Mechanisms for storing and accessing episodes
8. Consolidation: Process of stabilizing memories after initial encoding

9. Reconsolidation: Modification of existing memories upon retrieval

10. Properties:

11. Medium Capacity: Larger than working memory, smaller than semantic
12. Medium Duration: Memories persist for days to years
13. Autobiographical Content: Personally experienced events
14. Event-Based Structure: Organized around discrete episodes

Semantic Memory (Long-Term Memory)¶

The Semantic Memory tier provides long-term storage for general knowledge and facts:

1. Core Components:
2. Knowledge Base: Repository of general knowledge
3. Concept Network: Interconnected network of concepts and their relationships
4. Factual Information: Storage for facts independent of episodic context

5. Schema Organization: Structured frameworks for organizing knowledge

6. Processing:

7. Encoding/Retrieval: Mechanisms for storing and accessing semantic information
8. Semantic Embedding: Vector representations of concepts

9. Semantic Association: Connections between related concepts

10. Properties:

11. Large Capacity: Virtually unlimited storage
12. Long Duration: Persistent storage for years to lifetime
13. Hierarchical Structure: Organized in taxonomic networks
14. High Persistence: Resistant to decay over time

Memory Tier Interactions¶

The memory tiers interact through several mechanisms:

1. Consolidation: Process by which memories are transferred from working memory to episodic memory, and from episodic to semantic memory
2. Memory Transfer: Movement of information between tiers based on relevance and usage
3. Memory Promotion: Elevation of important memories to more persistent tiers
4. Memory Degradation: Gradual fading of memories that aren't accessed frequently

Cross-Tier Functions¶

Several functions operate across all memory tiers:

1. Cross-Tier Search: Ability to search for information across all memory tiers
2. Assisted Recall: Using information from one tier to aid retrieval from another
3. Memory Integration: Combining information from multiple tiers
4. Memory Reinforcement: Strengthening memories through repeated activation

The memory tier system is designed to mimic human memory processes, with information flowing between tiers based on frequency of use, relevance, and importance.