Can prediction and retrodiction explain whether frequent multi-word phrases are accessed 'precompiled' from memory or compositionally constructed on the fly?

An important debate on the architecture of the language faculty has been the extent to which it relies on a compositional system that constructs larger units from morphemes to words to phrases to utterances on the fly and in real time using grammatical rules; or a system that chunks large preassembled, stored units of language from memory; or some combination of both approaches. Good empirical evidence exists for both 'computed' and 'large stored' forms in language, but little is known about what shapes multi-word storage/ access or compositional processing. Here we explored whether predictive and retrodictive processes are a likely determinant of multi-word storage/ processing. Our results suggest that forward and backward predictability are independently informative in determining the lexical cohesiveness of multi-word phrases. In addition, our results call for a reevaluation of the role of retrodiction in contemporary language processing accounts (cf. Ferreira and Chantavarin, 2018).