YawnStim: a standardized and diverse video stimulus set.

In humans, contagious yawning is often elicited experimentally using a video stimulus, and individual differences in this response may be indicative of variation in important aspects of social cognition. However, researchers often use different and highly variable stimulus sets, making comparisons between studies and across conditions difficult. The lack of participant diversity within existing stimulus sets also limits the generalizability of previous findings. Here, a free stimulus set called YawnStim is described. YawnStim includes a series of standardized experimental and control videos from a diverse sample of men and women from the following self-identified categories: Caucasian, Black, Hispanic/Latino, and Asian. Videos are compiled into four conditions, including both (1) uncovered and (2) covered yawns, as well as (3) mouth closed and (4) mouth gaping controls. This stimulus package was validated in a series of five within-subjects laboratory experiments. Collectively, results from the individual experiments and accompanying mini meta-analyses demonstrated that both the uncovered and covered yawning conditions produced amplified self-reported yawning responses. Potential follow-up research both in terms of validation and further applications of YawnStim are discussed.