Presentation and validation of the DuckEES child and adolescent dynamic facial expressions stimulus set.

The stimulus sets presently used to study emotion processing are primarily static pictures of individuals (primarily adults) making emotional facial expressions. However, the dynamic, stereotyped movements associated with emotional expressions contain rich information missing from static pictures, such as the difference between happiness and pride. We created a set of 1.1 s dynamic emotional facial stimuli representing boys and girls aged 8-18. A separate group of 36 individuals (mean [M] age = 19.5 years, standard deviation [SD] = 1.95, 13 male) chose the most appropriate emotion label for each video from a superset of 250 videos. Validity and reliability statistics were performed across all stimuli, which were then used to determine which stimuli should be included in the final stimulus set. We set a criterion for inclusion of 70% agreement with the modal response made for each video. The final stimulus set contains 142 videos of 36 actors (M age = 13.24 years, SD = 2.09, 14 male) making negative (disgust, embarrassment, fear, sadness), positive (happiness, pride), and neutral facial expressions. The percent correct among the final stimuli was high (median = 88.89%; M = 88.38%, SD = 7.74%), as was reliability (κ = 0.753).