Sensitivity to temporal synchrony in audiovisual speech in early infancy: Current issues and future avenues

Audiovisual speech integration during infancy is crucial for socio-cognitive development. A key perceptual cue infants use to achieve this is temporal synchrony detection. Although the current developmental literature on this ability is rich, unsolved disagreements obscure the interpretation of findings. Here, we propose conceptual and methodological issues that may have contributed to a still unclear picture of the developmental trajectory of sensitivity to temporal synchrony, particularly when studied in audiovisual fluent speech. We discuss several sources of confusion, including a lack of terminological precision, heterogeneity in the experimental manipulations conducted, and in the paradigms and stimuli used. We propose an approach that clarifies the definition and operationalization of sensitivity to temporal synchrony and explores its developmental course, emphasizing the role of infants ' linguistic experiences. Ultimately, we expect that our analytical review will contribute to the field by aligning theoretical constructs, proposing more fine-grained designs, and using stimuli closer to infants ' experiences.