Fig. 1.
Example of the used stimuli. From left to right: human faces, chimpanzee faces, monkey faces and dog faces displaying positive, relaxed/neutral and negative facial expressions
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.