[:en] Why the sound of water helps you sleep[:]
[:en]A 2012 study by Orfeu Buxton, an associate professor of biobehavioral health at Penn State, examined the distinctions between the sounds of abrupt threats and gradual non-threats, according to Live Science.

Read the full article here : Why the sound of water helps you sleep_ Study reveals how non-threatening noises are blocked out by the brain _ Daily Mail Online[:]