Superstition: Black cats are bad omens
Claire Benoist for Reader's Digest
The backstory: Despite centuries of royal treatment (Egyptians worshipped them; the Norse goddess Freya rode in a chariot pulled by them), cats took a big hit to their reputation in the 1200s, when Pope Gregory IX, waging a culture war on pagan symbols, damned cats as servants of Satan. As a result, cats—especially black ones—were killed across Europe. One unintended consequence, according to some historians: The cat-deprived continent may have allowed disease-carrying rodents to flourish and spread the bubonic plague of 1348.
Rumors that the feline’s fangs and fur were venomous persisted, and by the witch-hunting days of the 1600s, many Puritans believed black cats to be “familiars”—supernatural demons that serve witches—and avoided them (to borrow an apt phrase) like the plague.
This is the science behind why we believe in superstitions.