Surprisal Theory is Tautological (without Rational Grounding)

Surprisal theory in psycholinguistics is tautological without rational grounding, paper argues

A new arXiv preprint argues that surprisal theory — the claim that human linguistic processing difficulty is an affine function of surprisal under some language model — is unfalsifiable without additional constraints, because for any difficulty measure a language model can be constructed to match it. The paper identifies that two decades of psycholinguistic work implicitly assumed the relevant language model was the corpus-generating distribution, an assumption recent empirical work has undermined by showing better corpus models can be worse predictors of processing difficulty. The author concludes that breaking the tautology requires deriving the relevant language model from a rationalist, non-empirically motivated model of the comprehender (e.g., based on memory constraints or processing goals).