AI Models Collapse When Trained on Recursively Generated Data

Shumailov et al., 2024, AI models collapse when trained on recursively generated data (Nature, vol. 631)

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2 cards in “Theoretical intuition” · whole deck

Theoretical intuition

  1. Why must recursive training on a discrete distribution collapse even with perfect fitting?
    With \(M\) samples, a state of probability \(q \le 1/M\) is expected to appear less than once, so it is likely lost. Viewed as a Markov chain, the only absorbing states are delta functions (all samples identical), so with probability 1 the process ends in a single state, losing all information.
    generation 010 of 10 valuesgeneration 57 of 10 valuesgeneration 303 of 10 values
    Each generation is fitted to 40 samples from the previous one: tails vanish first (simulation, not from the paper)
  2. What does the Gaussian model collapse theorem state?
    If each generation fits a Gaussian with unbiased mean and variance estimates from a fixed number of samples of the previous generation, then the approximation drifts arbitrarily far from the original (in Wasserstein-2 distance) while its variance collapses to zero, with probability 1.

Source

  • Ilia Shumailov, Zakhar Shumaylov, Yiren Zhao, Nicolas Papernot, Ross Anderson and Yarin Gal. 2024. AI models collapse when trained on recursively generated data. In Nature, vol. 631, pp. 755–759. License: CC BY 4.0. Flashcards adapted from this work. doi:10.1038/s41586-024-07566-y