Early-life microbiota in the LIMIT cohort: unveiling meconium microbiota types beyond maternal lifestyle.

Isochronous sequences are sequences in which successive events occur at equal inter-onset intervals, where the inter-onset interval is the time from the onset of one event to the onset of the next. Such sequences provide a useful way to study how observers form expectations about when a future event should occur. In the present task, participants judged whether the final event in a six-event sequence occurred earlier or later than the time predicted by the preceding regular rhythm. We therefore distinguish temporal sensitivity, measured by the just noticeable difference (JND), from perceived timing, measured by the point of subjective equality (PSE). The JND indexes how precisely participants discriminated early from late final events, whereas the PSE indexes the physical deviation from exact isochrony (anisochrony) at which the final event was equally likely to be judged early or late. Several theoretical accounts predict that regular sequences can support temporal prediction, but they differ in mechanism and in the aspect of temporal judgement they emphasise. Clock-based accounts describe timing in terms of accumulated pulses or internal temporal representations (Creelman ; Treisman ; Povel ; Wearden ). Multiple-look and perceptual-averaging accounts propose that repeated interval samples can reduce uncertainty about the expected time of a subsequent event (Drake and Botte ; Schulze ). Dynamic Attending Theory and related entrainment accounts propose that rhythmic context can guide attention to expected moments in time (Jones and Boltz ; McAuley and Jones ). These accounts share the general prediction that temporal regularity can support better discrimination, but they do not require the same interpretation for all forms of temporal judgement. For example, changes in perceived duration and changes in precision can dissociate across tasks and stimulus conditions. Temporal judgments also depend on sensory modality Di Stefano & Spence (). Auditory signals generally support more precise temporal discrimination than visual signals (Repp and Penel ; Stauffer et al. ; McAuley and Henry ; Fornaciai et al. ). Auditory and visual markers can also differ in their effective perceptual latencies. They can also shift a decisional reference point, defined here as the subjective criterion used to decide whether the final event occurred before or after the expected isochronous time. Such latency or criterion differences can produce systematic biases in perceived timing and perceived duration for intervals bounded by markers from different sensory modalities (crossmodal intervals; Hirsh and Sherrick ; Sternberg and Knoll ; Grondin et al. ; Mayer et al. ).