Over the centuries, many cultures have turned to purifying baths to cleanse both body and spirit. Ritual bathing was an integral part of Roman, Greek, Middle Eastern, and Japanese societies, and people washed themselves before entering a temple or undertaking spiritual activities.

Things aren’t so different today: Washing before prayer is common among Muslims, Catholics dip their hands in holy water upon entering a church, and Native Americans take vapor baths to purify and pray. More secular people, too, link physical and moral cleansing, believing that we can “wash away” doubts, fears, and regrets and start over “clean,” research finds.