Emotional faces passive viewing task diagram.

<p>In the position of the second slide above, images were randomized across 80 trials, in which 4 expressions (Happy, Sad, Angry, Neutral) from 10 female and 10 male actors from the NimStim set [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0200340#pone.0200340.ref041" target="_blank">41</a>] were each presented one time. The same mask (third slide above) was presented on each trial and was matched on luminance and low-level visual salience components to the face stimuli.