
Learning Length-Extrapolatable Recurrent Models
This paper studies why recurrent models trained with backpropagation through time fail to generalize beyond their training sequence length, arguing the cause is not just vanishing/exploding gradients but the quality of 'state credit' — the signal linking future losses to earlier recurrent states. The authors propose Credit Stabilization through Time (CST), a backward-pass technique that rescales state-credit signal norms without altering forward computation, and show it improves extrapolation up to 128x the training length on both synthetic and real-data tasks.
What it claims
Beyond what the summary states, the abstract makes a specific empirical argument for why gradient decay is not the culprit: dense per-token losses can still train a shared recurrent rule "despite severe decay," so decay alone does not determine whether learning fails. This is the observation that motivates reframing the problem around state credit rather than gradient magnitude.
How it works
Two details the summary does not carry. First, the rescaling is direction-preserving: CST "locally rescales the state-credit signal to stabilize its norm without rotating the component being corrected" — it changes magnitude, not direction, of the credit signal, and only in the backward pass. Second, CST is not a single method: because "controlled synthetic tasks and real data exhibit different credit dynamics," the authors specialize CST separately to each regime. So adopting this means picking (or deriving) a regime-appropriate variant rather than applying one uniform rule.
Evidence
The abstract reports gains beyond the training horizon "at up to 128x the training length" on both synthetic and real data. No baseline numbers, metrics, task names, model sizes, or compute are given on this page — only the extrapolation multiple and the two-regime split.
Limits
This is an abstract-only arXiv page (submitted 8 Sep 2026); there are no tables, hyperparameters, baselines, or ablations to inspect. Key things a reader must check in the PDF before relying on it: what the "different credit dynamics" between synthetic and real data actually are and how the two CST specializations differ concretely; what tasks and models the 128x claim covers; and whether the direction-preserving rescale interacts with the parameter update in a way that needs tuning per architecture. The claim that decay does not determine failure is asserted here, not demonstrated on the page.
Techniques named here
- Credit Stabilization through Time
Related in research



