Examples of images displaying the ranked faces morphed between a neutral and a fearful expression.

<p>Faces shown contain 0%, 20%, 40%, 60%, 80%, and 100% fear (images adapted from Fiorentini and Viviani [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131604#pone.0131604.ref033" target="_blank">33</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131604#pone.0131604.ref034" target="_blank">34</a>]). Reprinted from Fiorentini and Viviani [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131604#pone.0131604.ref034" target="_blank">34</a>] under a CC BY license, with permission from C Fiorentini, original copyright 2011.