Maintenance of subcategorical information during speech perception: revisiting misunderstood limitations.

Accurate word recognition is facilitated by context. Some relevant context, however, occurs after the word. Rational use of such "right context" would require listeners to have maintained or about the word, thus allowing for consideration of possible alternatives when they encounter relevant right context. A classic study continues to be widely cited as evidence that subcategorical information maintenance is limited to highly ambiguous percepts and short time spans (Connine et al., 1991). More recent studies, however, using other phonological contrasts, and sometimes other paradigms, have returned mixed results. We identify procedural and analytical issues that provide an explanation for existing results. We address these issues in two reanalyses of previously published results and two new experiments. In all four cases, we find consistent evidence both limitations reported in Connine et al.'s seminal work, at least within the classic paradigms. Key to our approach is the introduction of an ideal observer framework to derive normative predictions for human word recognition expected if listeners maintain and integrate subcategorical information about preceding speech input rationally with subsequent context. We test these predictions in Bayesian mixed-effect analyses, including at the level of individual participants. While we find that the ideal observer fits participants' behavior better than models based on previously proposed limitations, we also find one previously unrecognized aspect of listeners' behavior that is unexpected under existing model, including the ideal observer.