For over a century, scientists believed that light, focus distance, and cognitive effort were the main forces behind changes in pupil size. But a new discovery adds breathing to that list. Researchers ...

Two years ago, I published a nine-part series, "The Vagus Nerve Survival Guide to Combat Fight-or-Flight Urges." The genesis came from an "Aha!" moment when I noticed a pattern of diverse scientific ...

Researchers have discovered a fundamental mechanism that affects the size of the pupil, namely our breathing. The study shows that the pupil is smallest during inhalation and largest during exhalation ...