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<h1 class="text-4xl font-bold mb-2">JEPA and Cognitive Architectures</h1>
<p class="text-xl opacity-90">A Comprehensive Introduction to Predictive AI Systems</p>
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<li><a href="#motivation" class="text-indigo-600 hover:text-indigo-800 font-medium">Motivation</a></li>
<li><a href="#jepa-core" class="text-indigo-600 hover:text-indigo-800 font-medium">JEPA Core</a></li>
<li><a href="#cognitive-arch" class="text-indigo-600 hover:text-indigo-800 font-medium">Cognitive Architecture</a></li>
<li><a href="#modules" class="text-indigo-600 hover:text-indigo-800 font-medium">Modules</a></li>
<li><a href="#examples" class="text-indigo-600 hover:text-indigo-800 font-medium">Examples</a></li>
<li><a href="#conclusion" class="text-indigo-600 hover:text-indigo-800 font-medium">Conclusion</a></li>
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<!-- Motivation Section -->
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<span>1. Motivation and Background</span>
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<h3 class="text-xl font-semibold mt-6 mb-3 text-gray-700">1.1 The Need for Predictive Representations</h3>
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Modern AI systems must <span class="font-medium">perceive</span>, <span class="font-medium">reason</span>, and <span class="font-medium">act</span> in complex, dynamic environments. Human intelligence excels not because we memorize every detail, but because we <span class="font-medium">summarize</span>, <span class="font-medium">predict</span>, and <span class="font-medium">plan</span> using abstract representations—ignoring irrelevant noise and focusing on what is useful for future reasoning or action.
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Recent advances in deep learning (e.g., large language models, vision transformers) have shown the power of self-supervised representation learning. However, standard architectures (like autoregressive models) are often forced to model all details, including noise and unpredictability, limiting robustness and sample efficiency.
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<h3 class="text-xl font-semibold mt-6 mb-3 text-gray-700">1.2 Enter JEPA: Joint Embedding Predictive Architecture</h3>
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Proposed by Yann LeCun and colleagues, <span class="font-medium text-indigo-700">JEPA</span> offers a novel approach:
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<li><span class="font-medium">Learn representations by predicting only what is predictable</span>—not every detail, but the essential structure that allows for accurate reasoning and planning.</li>
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<p class="font-medium text-gray-800">Key Insight:</p>
<p>JEPA focuses on learning the predictable aspects of data while ignoring unpredictable noise, leading to more robust and efficient representations.</p>
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<span>2. JEPA: Core Ideas and Mechanism</span>
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<h3 class="text-xl font-semibold mt-6 mb-3 text-gray-700">2.1 What is JEPA?</h3>
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<span class="font-medium text-indigo-700">JEPA (Joint Embedding Predictive Architecture)</span> is a self-supervised learning framework where a model is trained to embed contexts (observed parts) and targets (future or missing parts) into a shared semantic space.
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<p class="font-medium text-blue-800">Objective:</p>
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<li>If the context and target belong together (e.g., two halves of the same image, or a sentence and its continuation), their embeddings should be <span class="font-medium">close</span>.</li>
<li>If they do not (random combinations), their embeddings should be <span class="font-medium">far apart</span>.</li>
<li>This is typically implemented via a <span class="font-medium">contrastive loss</span>.</li>
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<h3 class="text-xl font-semibold mt-6 mb-3 text-gray-700">2.2 Why Is This Powerful?</h3>
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<h4 class="font-semibold mb-2">Focuses on Structure</h4>
<p class="text-sm text-gray-600">Encodes only predictable, meaningful features while ignoring noise</p>
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<h4 class="font-semibold mb-2">Multi-Modal</h4>
<p class="text-sm text-gray-600">Works for vision, language, audio, video, and more</p>
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<h4 class="font-semibold mb-2">Transferable Features</h4>
<p class="text-sm text-gray-600">Learns representations useful for reasoning and planning</p>
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<h3 class="text-xl font-semibold mt-6 mb-3 text-gray-700">2.3 The JEPA Training Loop</h3>
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<p class="mt-2 font-medium">Context Encoder</p>
<p class="text-sm text-gray-600">Takes observed input</p>
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<p class="mt-2 font-medium">Embedding Space</p>
<p class="text-sm text-gray-600">Shared representation</p>
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<p class="mt-2 font-medium">Target Encoder</p>
<p class="text-sm text-gray-600">Takes future/missing part</p>
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<p class="font-medium">Input Context</p>
<p class="text-sm">(e.g., left image half)</p>
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<p class="font-medium">Similarity</p>
<p class="text-sm">Contrastive Loss</p>
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<p class="font-medium">Input Target</p>
<p class="text-sm">(e.g., right image half)</p>
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<h4 class="font-semibold mt-6 mb-2 text-gray-700">Concrete Examples:</h4>
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<h5 class="font-medium">Vision Example</h5>
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<li>Context: Left half of a cat image</li>
<li>Target: Right half</li>
<li>Embeddings should be close if they come from the same photo, far otherwise</li>
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<h5 class="font-medium">Language Example</h5>
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<li>Context: "The cat sat on the"</li>
<li>Target: "mat"</li>
<li>Close if the sequence is real, far if target is random</li>
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<span>3. From Representation to Reasoning: JEPA in Cognitive Architectures</span>
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JEPA shines as a <span class="font-medium">perception module</span> within a larger, <span class="font-medium">modular cognitive agent</span>. This mirrors biological systems: sensory organs and cortex encode perceptions, while higher reasoning and planning are handled by specialized systems.
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<h3 class="text-xl font-semibold mt-6 mb-3 text-gray-700">3.1 The Modular Agent</h3>
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The LeCun-style architecture for an intelligent agent typically includes:
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<h4 class="font-medium">1. Perception Module (JEPA)</h4>
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<p class="text-sm text-gray-700">Encodes current observation into a compact, predictive embedding</p>
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<h4 class="font-medium">2. Short-term Memory</h4>
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<p class="text-sm text-gray-700">Stores recent sequence of embeddings (history)</p>
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<h4 class="font-medium">3. World Model</h4>
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<p class="text-sm text-gray-700">Integrates the sequence to produce a latent state</p>
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<h4 class="font-medium">4. Configurator</h4>
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