The smiles stimuli were collected from the UvA-NEMO dataset. A total of 60 videos were randomly selected for this experiment. We created four categories out of these 60 videos, namely PV (paired videos), PI (paired images), SV (single video), and SI (single image). When the same person was viewed by observers in both real and posed smile videos, we report this as “paired videos”, otherwise we use the term “single video”.