The hierarchical modulation effects of perceptual grouping and peripheral cue validity on temporal order perception

Temporal order perception (TOP), a fundamental cognitive function that enables decoding of event timing, is influenced by perceptual grouping and attention, yet the role of cue validity in the interactive modulation of these two factors remains unclear. The present study adopted C-shaped stimuli composed of three line segments as experimental materials. Drawing on the grouping principle of closure, two experiments were conducted to examine the interactive effects of perceptual grouping and peripheral cues with non-predictive validity (50%, Experiment 1) and counter-predictive validity (20%, Experiment 2) on TOP. The results demonstrated that perceptual grouping facilitates simultaneity perception but impairs sequential perception. Notably, this dual effect of perceptual grouping on TOP is independent of both the validity and predictability of peripheral cues. Furthermore, the prior entry effect was enhanced by non-predictive peripheral cues but attenuated by counter-predictive ones. Perceptual grouping significantly reduced the modulatory effect of attention on TOP. Overall, these findings confirm a hierarchical modulation mechanism of TOP, in which the effect of perceptual grouping takes precedence over that of spatial attention in regulating TOP, and thus provide novel empirical and theoretical insights into the cognitive mechanisms of temporal order processing.