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. 2013 Dec 10;1:e223. doi: 10.7717/peerj.223

Figure 1. Stimulus images used in the present study.

Figure 1

In Experiment 1, the subject was presented seven images of chimpanzee faces in the three categories of unfamiliar, familiar, and selfimages. In Experiment 2, the subject was presented six images of human faces with unfamiliar and familiar categories. Note that only one example of each category is shown for Experiment 2 for privacy protection.