  Training facial emotion recognition models requires large sets of data and
costly annotation processes. To alleviate this problem, we developed a gamified
method of acquiring annotated facial emotion data without an explicit labeling
effort by humans. The game, which we named Facegame, challenges the players to
imitate a displayed image of a face that portrays a particular basic emotion.
Every round played by the player creates new data that consists of a set of
facial features and landmarks, already annotated with the emotion label of the
target facial expression. Such an approach effectively creates a robust,
sustainable, and continuous machine learning training process. We evaluated
Facegame with an experiment that revealed several contributions to the field of
affective computing. First, the gamified data collection approach allowed us to
access a rich variation of facial expressions of each basic emotion due to the
natural variations in the players' facial expressions and their expressive
abilities. We report improved accuracy when the collected data were used to
enrich well-known in-the-wild facial emotion datasets and consecutively used
for training facial emotion recognition models. Second, the natural language
prescription method used by the Facegame constitutes a novel approach for
interpretable explainability that can be applied to any facial emotion
recognition model. Finally, we observed significant improvements in the facial
emotion perception and expression skills of the players through repeated game
play.
