The "inverted-U" of cognitive effort across speech rates holds for simple but not complex sentence structures.

ABSTRACT: Pupil dilation has become a well-established physiological index of cognitive effort. Here we examined the often-cited finding of an inverted U-shaped function of pupil size across the continuum from highly degraded to clear speech. Unlike the short sentences with simple syntax as used in the original inverted-U demonstrations, 32 young adults recalled sentences with subject-relative embedded clause structures and more syntactically complex object-relative embedded clause structures. Sentences were degraded using time-compression and presented at 10, 25, 35 and 100% of their normal playing time selected from a preliminary calibration study. Subject-relative sentences showed an approximately symmetrical inverted U-shaped function across speech rates, but object-relative sentences failed to

SUBMITTER: O'Leary RM 

PROVIDER: S-EPMC12614458 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature