Testing the "RL catching up to bigger pretrains" hypothesis against METR timelines

austinc3301 · x · 2026-11-10

A substantive thread debating what drives AI capability gains. The author argues that if Cohen's hypothesis—RL merely catching up to a bigger pretrained base—were true, we'd expect diminishing marginal returns, since eliciting existing capabilities should be RL's easiest job. Yet growth didn't slow (23, then 29 pts/yr after Mythos). A follow-up notes the hypothesis is testable: if the bigger pretrain (arriving with Mythos in Feb 2026) drove the speedup, the acceleration should start then, but METR data with error bars place the start in Oct 2025, 4 months earlier (85% likely)—though Models 2-4 may themselves be new pretrains, leaving uncertainty.

Related event: Independent Test: AI Acceleration Predates Mythos by Four Months(2 posts)→

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