Author: Martin Schaefer, Postdoctoral Researcher in Cognitive Neuroscience and Behavioral Psychology, Karolinska Institutet

You have probably heard the saying that the eyes are the windows to the soul, but now it turns out that they are also connected to how we breathe. Scientists have long studied the size of our pupils to understand attention, emotion and even medical conditions. But now, new research has surprisingly revealed that they change size in sync with our breathing. Our pupils are never static; they constantly adjust in response to both external and internal factors. The most well known is that they control how much light enters the eye, just like a camera aperture. You can easily…