An interesting framing that the Internet was the perfect product complement to next-token prediction. And poses the question of whether there a perfect product complement to RL.
Thread (22 posts)
What does it mean for a curriculum to be "smooth" and how does the Internet have a smooth curriculum of difficulty?
This is a fascinating question that gets at the heart of how learning systems can efficiently scale from simple to complex skills.
What is a "Smooth" Curriculum?
A smooth curriculum means that the difficulty progression has minimal gaps - each step builds incrementally on the previous one without requiring sudden leaps in capability. Think of it like a well-designed math textbook that introduces addition before multiplication, polynomials before calculus, etc.
In machine learning terms, a smooth curriculum ensures that:
- The model can always find some signal to learn from at its current capability level
- There's a natural progression path from basic to advanced concepts
- The model isn't overwhelmed by tasks far beyond its current ability
How the Internet Provides This
The internet naturally contains this smooth progression because it serves humans at all skill levels:
Knowledge Pyramid:
- Elementary explanations (Khan Academy, Wikipedia introductions)
- Intermediate tutorials (Stack Overflow answers, blog posts)
- Advanced discussions (research papers, technical forums)
- Cutting-edge content (arXiv preprints, expert debates)
Redundant Explanations: The same concept gets explained at multiple difficulty levels by different authors, giving the model many "practice problems" at each level.
Implicit Prerequisites: When someone writes about advanced topics, they often reference or briefly explain prerequisite concepts, creating natural bridges between difficulty levels.
Why This Matters for RL
For reinforcement learning, this becomes even more critical because:
- Sparse Rewards: RL agents need to discover any positive reward before they can optimize further
- Exploration Challenge: Without a smooth curriculum, agents might never stumble upon the right actions
- Skill Composition: Complex behaviors emerge from combining simpler learned skills
The internet worked so well for next-token prediction because it provided this curriculum "for free" - no manual curation needed. The challenge for RL is finding a similar naturally-occurring smooth curriculum in reward signals.
What's your intuition about where such smooth reward curricula might emerge naturally?
If we're saying that the Internet offered a smooth curriculum for next token prediction does that mean that during pretraining the order in which the dataset is consumed matters eg so the model learns to predict easier tokens first and then harder tokens later? If so, does that ordering come from the human or is that somehow emergent in the training process?
This is a subtle but important distinction! The "smooth curriculum" property of the internet doesn't primarily come from the temporal ordering during training, but rather from the statistical co-occurrence of concepts at different difficulty levels within the dataset.
How the Curriculum Actually Works
When we say the internet provides a smooth curriculum, we mean:
-
Spatial Co-occurrence: Easy and hard concepts appear together in the same documents
- A Wikipedia article on calculus starts with basic definitions
- A Stack Overflow answer includes both the solution and explanatory context
- Research papers cite and briefly explain prerequisite concepts
-
Statistical Gradients: The model learns to predict tokens based on context, and the internet naturally provides contexts that bridge difficulty levels
- Simple explanations are statistically more common
- Complex concepts are usually surrounded by simpler explanatory text
- The model learns representations that capture this difficulty gradient
Training Order vs. Dataset Structure
Training Order: Modern pretraining typically uses random shuffling or simple heuristics. The specific order of documents during training is usually not carefully curated for curriculum purposes.
Dataset Structure: The curriculum emerges from the content structure of internet text itself - how concepts are naturally explained and connected by human authors.
Emergent vs. Designed
This is mostly emergent rather than designed:
- Human authors naturally provide context and build up to complex ideas
- The internet's diversity means concepts get explained at multiple levels
- No central planner designed this curriculum - it emerged from millions of people writing for different audiences
Some modern work does explore designed curriculum orderings (like starting with higher-quality data), but the core insight is that the internet's intrinsic structure provides the curriculum, not the training sequence.
The question for RL is: can we find reward structures that have this same emergent curriculum property?
I think the key idea here is that human authored content will often have simple explanations that surround complex concepts. A few implications I see:
- Across many pieces of content simple explanations will be statistically more common which gives models relatively more opportunities to get reward signals from trying to predict simpler tokens.
- Since simple explanations often proceed the complex concepts models will have more opportunities to try to predict the simpler tokens first before proceeding to the harder tokens
And because of this intrinsic structure of human authored content, the Internet inherits this structure as a whole.
Let me challenge these statements with some critical counterpoints:
Statistical Frequency ≠ Learning Difficulty
Critique: Simple explanations being more common doesn't necessarily mean they provide better learning signals. Consider:
- Diminishing returns: Once a model learns basic concepts, additional simple examples may provide minimal learning benefit
- Information density: Complex technical content might be more information-dense and provide stronger gradients for learning
- Tokenization artifacts: What we consider "simple" linguistically may not align with what's computationally easier to predict
Sequential Structure May Not Matter
Critique: The claim that "simple explanations often precede complex concepts" has several issues:
- Attention mechanism: Transformers process entire sequences simultaneously, not sequentially. The model sees all tokens at once during training
- Bidirectional context: Models learn to predict tokens using both preceding AND following context
- Document structure variance: Many internet texts don't follow this pattern - think tweets, forum posts, or technical documentation that jumps right into complex topics
Human Authoring Assumptions
Critique: The assumption about human authoring patterns may be flawed:
- Expert content: Much internet content is written by domain experts for other experts, skipping basic explanations
- Cultural/linguistic bias: This pattern might only hold for certain types of content (educational) or certain languages/cultures
- Selection bias: We might be cherry-picking examples that fit this narrative while ignoring counter-examples
The "Inheritance" Fallacy
Critique: Just because individual documents have this structure doesn't mean the internet as a whole inherits it:
- Aggregation effects: Random sampling during training might destroy any sequential curriculum benefits
- Scale effects: At internet scale, the sheer volume of complex content might overwhelm simple explanations
- Distribution mismatch: The model's training objective (next-token prediction) may not align with human pedagogical structures
What evidence would we need to actually validate these claims empirically?