Eternal Recall isn't built on marketing claims. It's built on peer-reviewed cognitive science research spanning decades. Here are the foundational papers.

These papers describe the ACT-R cognitive architecture—the same memory models that Eternal Recall implements for AI. We provide both links to the original papers and accessible summaries.

📚 A Note on Academic Papers

Academic papers can be dense. We've written plain-English summaries of each paper's key contributions. Click the links to access the original research.

Tutorial

Understanding ACT-R: An Outsider's Perspective

Author: Jacob Whitehill
Machine Perception Laboratory, UC San Diego

What This Paper Covers

This is an accessible tutorial that explains ACT-R to people outside the cognitive science community. It provides clear explanations of the core mechanisms that are scattered across the original ACT-R literature.

Key Concepts Explained:

  • Declarative vs. Procedural Knowledge: The fundamental division between "knowing that" (facts) and "knowing how" (skills).
  • Chunks and Production Rules: How knowledge is represented in ACT-R.
  • Activation Equation: A(t) = B(t) + Σwjsij — the core equation determining memory accessibility.
  • Base-Level Learning: How recency and frequency affect memory strength.
  • The Spacing Effect: Why distributed practice is better than cramming.
  • Power Laws of Learning: Why recall latency follows a power function.

Why It Matters for Eternal Recall:

This paper provides the clearest explanation of the activation equations that Eternal Recall implements. The base-level learning equation (how memories strengthen and decay) and the spreading activation equation (how context affects recall) are directly implemented in our system.

"The activation A(t) of a knowledge chunk is the log-odds that, at time t, it will match to some production rule that ends up firing."

— From the paper, explaining what activation actually represents

Key Equations from This Paper:

Activation: A(t) = B(t) + Σwjsij

Base-level activation plus spreading activation from context

Base-Level: B(t) = ln(Σtk-d) + β

Sum of decayed access events, plus constant

Recall Probability: P(t) = 1 / (1 + e-(A(t)-τ)/s)

Sigmoid function determining recall success

Foundational ACT-R Literature

These are the seminal works that established ACT-R as a cognitive architecture:

The Atomic Components of Thought

Anderson, J. R., & Lebiere, C. (1998)

The definitive book on ACT-R architecture. Establishes the production system, declarative memory, and goal stack mechanisms.

Book - Lawrence Erlbaum Associates 📚 View on Amazon

An Integrated Theory of the Mind

Anderson, J. R., Bothell, D., Byrne, M. D., et al. (2004)

Describes ACT-R as an integrated cognitive architecture with modular components. Published in Psychological Review.

Journal Article - Psychological Review 📄 PubMed 📄 ResearchGate (PDF)

Rules of the Mind

Anderson, J. R. (1993)

Introduces ACT-R and the "rational" optimization approach. Key text for understanding the theoretical foundations.

Book - Lawrence Erlbaum Associates 📚 View on Amazon

The Fan Effect

Anderson, J. R., & Reder, L. M. (1999)

Explains interference-based memory—why having more associations can slow retrieval. Published in Journal of Experimental Psychology.

Journal Article 📄 APA PsycNet

An Integrated Theory of List Memory

Anderson, J. R., Bothell, D., Lebiere, C., & Matessa, M. (1998)

Applies ACT-R to serial memory recall, modeling human error patterns in list learning.

Journal Article 📄 ACT-R Archive

Practice and Retention: A Unifying Analysis

Anderson, J. R., Fincham, J. M., & Douglass, S. (1999)

Derives the power law of learning from ACT-R principles. Key paper for understanding decay mathematics.

Journal Article 📄 ACT-R Archive

Related Research

Other papers that influenced Eternal Recall's design:

Context-Dependent Memory in Two Natural Environments

Godden, D., & Baddeley, A. (1975)

Seminal research on how environmental context affects recall. Famous study of divers learning underwater. Published in British Journal of Psychology.

📄 Semantic Scholar

Short-Term Retention of Individual Verbal Items

Peterson, L., & Peterson, M. J. (1959)

Established the 8-18 second duration of short-term memory without rehearsal. Foundation for buffer decay timing. Published in Journal of Experimental Psychology.

📄 PubMed 📖 Summary

Primary Memory

Waugh, N. C., & Norman, D. A. (1965)

Distinction between primary (short-term) and secondary (long-term) memory systems. Published in Psychological Review.

📄 PubMed 📄 APA PsycNet

Spike Timing-Dependent Plasticity: A Hebbian Learning Rule

Caporale, N., & Dan, Y. (2008)

Neuroscience research on Hebbian learning that inspired the associative learning mechanism. Published in Annual Review of Neuroscience.

📄 Scholarpedia Overview 📄 ScienceDirect

Memory Activation and Diagnostic Reasoning

Mehlhorn, K., Taatgen, N.A., Lebiere, C., & Krems, J.F. (2011)

Application of ACT-R spreading activation to sequential diagnostic reasoning. Published in Journal of Experimental Psychology: Learning, Memory, & Cognition.

📄 PubMed 📥 Model Code & Data

From Research to Product

Eternal Recall is built on these foundational research findings:

📊 Activation Equation

ACT-R Research: A(t) = B(t) + Σwjsij

In Eternal Recall: Memories have accessibility that changes based on use and context, following the original ACT-R mathematical framework.

📉 Power Law Decay

ACT-R Research: B(t) = ln(Σtk-d)

In Eternal Recall: Memory accessibility follows a power law decay curve—fast initially, then stabilizing over time.

🕸️ Spreading Activation

ACT-R Research: Σwjsij context term

In Eternal Recall: The Knowledge Graph implements spreading activation between related concepts and memories.

⏱️ Buffer Decay

Research: Peterson & Peterson (1959) - short-term memory duration

In Eternal Recall: Recent discussion topics maintain contextual influence, based on cognitive science research.

🔗 Associative Learning

Research: Hebbian plasticity principles

In Eternal Recall: The system learns relationships between concepts through repeated co-activation.

📈 Retrieval Practice

Research: Memory access strengthens retention

In Eternal Recall: Accessing memories reinforces them, keeping frequently-used information readily available.

Note: While Eternal Recall is built on published ACT-R research, our specific implementation—including custom adaptations and optimizations for AI memory systems—is proprietary.

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