Catching a yawn: A multimodal experimental protocol for investigating sleepiness under visual and auditory yawning stimuli featuring human and digital characters

This protocol describes a laboratory-based experimental method for investigating whether exposure to contagious yawning stimuli is associated with measurable changes in subjective and physiological markers of sleepiness. The protocol employs a randomized within-subject crossover design comparing human versus digital character yawning stimuli, each presented with and without auditory cues. The method integrates validated subjective sleepiness assessments with multimodal physiological sensing including cardiovascular, electrodermal, pupillary, thermal, and neural activity measures. This protocol addresses a methodological gap in yawning research by shifting focus from yawning occurrence to downstream sleepiness-related state changes associated with yawning stimuli exposure, while also examining whether digitally presented yawning is comparable to human yawning. Standardized experimental protocol for assessing sleepiness associated with contagious yawning stimuli exposure Integration of subjective measures with multimodal physiological sensing for comprehensive state assessment Direct comparison of yawning stimuli of human versus digital characters.