Figure 1.
Yawn contagion frequency (mean and 95% confidence interval (CI)) as a function of the social bond shared by the subjects.
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.