Why magical thinking is so widespread – a look at the psychological roots of common superstitions

"Find a penny, pick it up. All day long, you'll have good luck." This common rhyme evolved from various superstitions, with a common theme being that metal was a gift from the gods and thus brought good fortune. The supposed lucky power of metal is the reason people tie tin cans to the back of newlyweds' cars. Pennies are also included in the Victorian wedding ritual: "Something old, something new, something borrowed, something blue, and a lucky penny in the shoe." These traditions are meant to bring good fortune to the new couple. 

Metal horseshoes are a common symbol hung on homes to bring good luck and protect against evil spirits. In the British Isles, malevolent fairies, goblins, witches and elves were supposed to be repulsed by iron, a strong metal able to withstand fire and drive away evil. Another origin story is that of St. Dunstan, the patron saint of blacksmiths in Catholicism, who tricked the devil by shoeing one of his cloven hooves. Dunstan then made a deal with the devil that he'd take the shoe off if the devil agreed to never enter a doorway with a horseshoe above it.

Rabbits have been associated with luck for thousands of years across Asia, Africa, Europe and the Americas, but this superstition's origins are thought to be in Western Europe before 600 B.C., according to the book "Extraordinary Origins of Everyday Things." Their prolific nature associated them with fertility and prosperity. Some cultures developed specific beliefs about what kind of rabbit's feet were considered lucky. For example, in West African hoodoo, the back left foot of a rabbit captured or killed in a cemetery by a red-headed, cross-eyed person during the full moon at midnight on Friday the 13th, the unluckiest of circumstances, was especially lucky.

If you don't want to carry around part of a rabbit, you could simply say the animal's name. According to a superstition that originated in the U.K., saying "rabbit" when you wake up on the first day of the month will bring you good luck for the month. The custom also caught on stateside as President Franklin Roosevelt reportedly said "rabbit, rabbit"at the beginning of each month, according to NPR. Variations include saying "white rabbits" or "bunny bunny," as was the habit of comedian Gilda Radner. If you forget in the morning, you can also say "black rabbits" or "tibbar, tibbar," which is "rabbit, rabbit" backwards, before going to sleep on the first night of the month. 

While singer-songwriter Alanis Morissette might consider rain on your wedding day ironic, many cultures consider this a good omen. Rain brings life, fertility and renewal, so rain on your wedding day is a sign of a prosperous union.

The tradition of putting candles on cakes has been traced back to the ancient Greeks, who would present cakes with glowing candles on top to Artemis, goddess of the moon, for her favor. The light was to mimic the moon, while the smoke above the candles carried their requests to the gods in the heavens. Other scholars link the practice to Germany and their celebration Kinderfest, in which a candle was supposedly placed on the cake to represent "the light of life." Nowadays, the tradition involves making a wish while attempting to blow out all the candles in one breath.

People in Denmark and some other European countries save their broken dishes throughout the year in order to throw them against the homes of friends and family on New Year's Eve to bring them luck. Less aggressive people will also leave broken dishes in a pile outside the home of someone in need of good fortune. In many cultures, glass breaking wards off evil spirits and foretells good fortune.

In Serbia, spilling water behind someone is a way to give them good luck ahead of a major event. One thought behind it is that giving back some of the life-giving liquid to the earth will in turn give the person good karma. Water also flows easily so the hope is that things would go as smoothly as spilling water. 

The number seven is considered a lucky number around the world not because of its use in slot machines but because of its magical and spiritual connotations. Many things occur naturally in sevens. Before the invention of the telescope, only seven planets were visible to early astronomers. There are seven seas, seven continents and seven colors in the rainbow as well as seven days of the week, seven wonders of the world, seven notes on a music scale, seven deadly sins and seven chakras. Because of this, the number often represents harmony, unity, completion, perfection and positive energy.

Another common gambling superstition is blowing on dice before rolling them. This good luck ritual is featured in many Hollywood films, and is thought to date back to when gambling still mostly took place on the streets and players would blow on the dice to clean them of street grime.

While breaking the wishbone at Thanksgiving is a more modern tradition, the concept of wishing on a fowl's fused clavicle, formally known as a furcula, came to the New World from England by way of ancient Romans who picked up the custom thousands of years ago from Etruria, an ancient Italian civilization. Etruscans believed birds had prophetic powers and would dry chicken furculas and make wishes on them. Romans added the element of two people breaking the bone together, with whoever ended up with the longer piece earning good fortune or a granted wish.

The expression "knock on wood" and the superstition of tapping on something wood for good luck can be traced back to Medieval Europe. Many ancient wooden churches claimed to contain wood from the cross, and congregants would touch the wood to connect with God for healing, good fortune and more. 

While it can also be a sign of deceit, crossing your fingers, specifically your forefinger and middle finger, for good luck and the expression "fingers crossed" are common superstitions for good luck, courage or support. In pre-Christian times, crosses were symbols of power and unity, so people would wish on their center points to ward off evil. This evolved to two people each using their pointer fingers to make the sign of the cross to call for God's favor or protection. Eventually this became a single person crossing their first two fingers.

A common superstition around the world is that if a bird poops on your head, car or other property, wealth is coming your way. That's because, despite the massive bird population, it's a seemingly rare occurrence. Both a New Zealand man and a Canadian woman credit bird poop for their winning lottery tickets, to the tune of $100,000 and $1 million, respectively. And NBA player Dwyane Wade claims he's been pooped on before two key moments in his basketball career.

In many Asian countries, people eat long noodles on New Year's Day to ensure a long life. The superstition in that you can't break, cut or shorten the noodles while cooking or eating them. In China, "longevity noodles" are eaten at other celebrations such as birthdays.

Pelting newlyweds with grain is meant to symbolize rain as well as shower the new couple with good fortune and fertility. The tradition can be traced back the ancient Romans, who originally threw wheat before rice superseded it as the preferred grain. There are many variation of tossing things at newly married couples, from symbolic candy in Italy to wish them sweetness in marriage or figs and raisins in Morocco to ensure fruitfulness. Many modern couples have adopted more aesthetically pleasing version of this send-off, such as rose petals, bubbles or sparklers.

Another Chinese good luck symbol is crickets, which Disney featured in its animated movie "Mulan." Their happy chirping noise mean crickets are often associated with joy and happiness, a connection found in the works of Shakespeare as well as Western fables concerning the crickets' cousin, the grasshopper. In many cultures, the cricket is a symbol of wealth, good luck, intuition and the prosperity of spring.

Ladybugs, also known as ladybirds, were considered a symbol of protection by medieval farmers, as the insects munch on aphids, which destroy crops. Thus, the superstition arose that it's good luck for a ladybug to land on you and that you shouldn't brush it away but rather accept the omen of safety, good health and prosperity.

In the Netherlands and Switzerland, newlyweds plant a pine tree outside their home to ensure luck and fertility in their marriage.

Celtic Druids believed rare four-leafed clovers could ward off evil spirits and give you the power to see demons and fairies. There are roughly 10,000 three-leaf clovers for every one four-leaf clover. 

Although they can be spotted in Chinese stores and restaurants, the waving "lucky cat" figurines called maneki neko, which means "beckoning cat," are actually Japanese. These good-luck figures come is just about every shape, size, expression, color and level or ornateness but usually depict a calico Japanese bobtail cat. There are a number of folktales and legends explaining its origins, but the cat is generally thought to attract customers, money and good fortune.

Originating in Turkey more than 3,000 years ago, the nazar is an eye-shaped bed or amulet meant to protect against the evil eye, which generally means any ill wishes and curses people might throw your way. While many cultures around the world have similar symbols, the nazar spread across the Mediterranean, and its field of blue with a black dot superimposed on a white background has become an icon of these cultures that is still used by locals to this day.)

Though the symbol has crossed over and can be spotted on t-shirts and necklaces at fast fashion retailers, the Hamsa hand's origins are as a amulet meant to protect against the evil eye. Also known as the Hand of Fatima, the Hamsa hand depicts an open right hand with an eye in the middle and is employed by Jews, Christians and Muslims alike in the Middle East and North Africa. The symbol is also thought to boost fertility in women, strengthen the weak, bring blessings and more.

Originating with the Native American Ojibwe (Chippewa) tribe, dream catchers are made from a hoop with a woven net inside meant replicate a spider's web. Adorned with beads or feathers, they are meant to protect children by placing them above their beds. They're meant to ward off or catch evil spirits and nightmares while allowing good dreams and positive energy to pass through. Dream catchers have become a ubiquitous symbol of Native American or First Nation cultures that has been appropriated and distorted over the years.

Wishing on a star is common, but the biggest celestial harbinger of luck is a shooting star. Many cultures believe wishes on shooting stars will come true. Other beliefs about shooting stars are that they can guarantee safe travels, bring money or cause a sick person to get better. 

In Spain and some other Spanish-speaking countries, people guarantee good luck in the new year by eating a dozen grapes, one at each stroke of midnight on New Year's Eve for each month to come.

An old superstition is that if your palm itches, it means you will soon receive money. In some parts of the world, if your right palm itches, it means money will come in, while the left itching means you'll be the one paying it out, while in others, it's vice versa.

Why is walking under a ladder bad luck? Aside from the fact that the person on the ladder could drop something on your head? This superstition may have religious roots. A ladder leaning against a wall creates a triangle, which is a symbol for the Holy Trinity in Christian tradition. Walking under the ladder supposedly “breaks” the Trinity.

Are black cats bad luck or good luck? It depends on who you ask. In some traditions they are an omen of prosperity. But Pilgrims in the early American colonies thought black cats were tied to witches. The witch trials are long over, but the stigma remains.

The taboo on opening an umbrella inside may date all the way back to ancient Egypt. Egyptians used umbrellas to protect themselves from the heat of the sun. Opening one indoors may have been seen disrespectful to the god of the sun.

A Filipino superstition holds that you should not go straight home after a funeral. If you do, death may follow you. So stop off somewhere else first.

Naval tradition holds that toasting someone with water (instead of alcohol) will doom them to death by drowning.

This goes beyond waking up on the wrong side of the bed. According to some traditions, it’s unlucky to sleep with your feet pointing toward your bedroom door. This apparently originates from the fact that a dead body is traditionally taken from a bedroom feet-first.

Putting your shoes on the table isn’t just bad manners, it could be bad luck. This may date to a British mining tradition, where the shoes of dead miner were placed on the table as a sign of respect.

Black cats aren’t the only animals with a bad reputation. Many ancient cultures hold that owls are harbingers of death.

The superstition that breaking a mirror is bad luck dates back to the ancient belief that “breaking up” your reflection breaks up your soul. But why seven years of bad luck? Ancient Romans apparently believed that the body took seven years to renew. So once you break that mirror, it takes a long time to repair things.

Ancient tradition holds that whatever you do to a robin will happen to you. So killing a robin is not a good idea.

Jewish tradition holds that it’s bad luck to set up a baby’s room before he or she is born. Some people also avoid baby showers.

Yellow flowers are said to signify the end of a relationship. (So avoid them on your next anniversary!)

White lilies are mostly closely associated with funerals, so in some traditions, it’s bad luck to make them part of other celebrations.

An ancient African superstition holds that women who eat goat meat could grow a beard.

According to this Eastern superstition, trimming your nails after dark could invite evil spirits into your home.

The administration of former President Carlos Menem is not remembered fondly in Argentina. He’s been blamed for, among other things, an economic crisis, a World Cup loss and even an earthquake. Now some think that just saying his name can bring bad luck.

You might think that walking backward is just a good way to exercise some different muscles. But in Portugal, it’s considered bad luck because the devil may follow you.

A superstition from the Philippines holds that you should not wear red during a storm. The color is thought to attract lightning.

Avoid taking a deep breath while passing a cemetery. Tradition holds that you could breathe in a soul.

You know not to step on a crack in the sidewalk. But what about a manhole cover? Sweden has a unique superstition about those. The covers are marked either “K,” for the Swedish word for fresh water, or “A,” for sewage. But “K” also represents the word for love and “A” heartbreak. So superstitious Swedes avoid stepping on the “A” covers.

According to some traditions, you’re putting your “best” foot forward when you’re entering a room with your right foot. It’s bad luck to go left-foot-first.

Some fishermen believe that fish won’t bite if bananas are onboard the boat. Bananas are even sometimes blamed for boats breaking down out on the water.

The number 13 is considered unlucky in much of the Western world. But other cultures have other superstitions. The number 4 is unlucky in China. The Chinese word for “four” sounds like the word for “death.”

Actors are a superstitious group. One of the most famous superstitions is that you should not say “Macbeth” in a theater. The story goes that many tragedies have befallen productions of Shakespeare’s play. So call it “The Scottish Play” backstage instead.

Wishing an actor good luck before a performance is also thought to bring bad luck. So theater folk instead “curse” each other with “break a leg” to ward off bad spirits.

Tradition holds that there’s a pot of gold at the end of a rainbow. But you might be pressing your luck if you point at that rainbow. Depending on the source, pointing at a rainbow could draw the energy from your body, cause warts or even make your finger fall off.

A series of terrorist attacks hit Paris and the northern suburb of Saint-Denis, Friday, Nov. 13, 2015. Six total attacks occurred, including mass shooting at an Eagles of Death Metal concert in the Bataclan theater that led to a stand-off with police. In total, the attackers killed 130 people and injured more than 400.

The Islamic State claimed responsibility for the attacks, which were the deadliest inflicted on France since World War II. 

In this photo, people light candles while paying their respect in front of The Belle Equipe restaurant in Paris, Saturday, Nov. 14, 2015. 

The Costa Concordia ran aground off the coast of Tuscany, overnight on Friday, Jan. 13, 2012, sending water pouring in through a 160-foot (50-meter) gash in the hull and forcing the evacuation of some 4,200 people from the listing vessel. Thirty-two passengers died, as well as one salvage crew member. The captain, who was heavily criticized for leaving the ship before the passengers, was later charged with manslaughter. 

Although the disaster occurred on Friday the 13th, the superstition is not shared among Italians, who generally consider Friday the 17th to be a day of bad luck.

The luxury cruise ship is shown here on it its side Saturday, Jan. 14, 2012. 

A rare early October snowstorm left parts of western New York blanketed with 2 feet of snow on the morning of Friday, Oct. 13, 2006, prompting widespread blackouts, closing schools and halting traffic. 

Trace amounts of snow that early in the season are common for the area, but the highest previously recorded total for October in Buffalo was 3.1 inches in 1972, according to weather.gov.

This photo shows downed trees blocking driving lanes in Buffalo, N.Y. 

The opening ceremony of the 2004 Olympic Games took place on Friday, Aug. 13, 2004. It marked the return of the Olympics to the city in which the modern games began in 1896.

Rapper Tupac Shakur died on Sept. 13, 1996. He was shot four times during a drive-by shooting in Las Vegas on Sept. 7, 1996.

Shakur is shown here speaking as fellow rap artist Snoop Doggy Dogg listens during a voter registration rally in South Central Los Angeles, on Aug. 15, 1996, file photo. 

Uruguayan Air Force Flight 571 was carrying 45 people when it crashed in the Andes on Friday, Oct. 13, 1972. Many died during the crash or later from cold temperatures, injuries and an avalanche that struck their shelter.

Sixteen of them survived 72 days in the Andes before they were rescued. Official sources said some of the survivors acknowledged eating parts of bodies to avoid starvation, according to the Associated Press.

Eight of the survivors are shown here huddling together in the craft's fuselage on their final night before rescue on Dec. 27, 1972. A mountain rescue team brought them food.

The Bhola cyclone that hit East Pakistan (present day Bengladesh) dissipated Friday, Nov. 13, 1970, after killing up to 500,000 people according to some counts.

It remains the deadliest tropical cyclone in recorded history.

This is an aerial view of devastation in the aftermath of the cyclone, Nov. 1970.

Catherine "Kitty" Genovese, a bar manager, was stabbed to death on Friday, March 13, 1964 as she returned home to the Kew Gardens section of Queens, New York at 3:20 a.m. According to police, 38 people looked on but did nothing as Genovese was stalked by her attacker and attacked three different times over the period of half an hour.

While details of the slaying were proven inaccurate over the decades, psychology instructors and students still operate off the original "parable" of bad Samaritans united in their indifference to distress, according to an article by three British professors. The incident led to what is commonly referred to as the "bystander effect."

Actor Steve Buscemi was born Friday, Dec. 13, 1957, in Brooklyn, New York.

Horror movie legend Alfred Hitchcock is often credited with being born on a Friday the 13th as well. However, Hitchcock was born on Aug. 13, 1899, which was a Sunday.

While bombs hit Buckingham Palace several times during World War II, the most serious instance occurred Sept. 13, 1940. The hit destroyed the palace's chapel

In this photo, Britain's King George VI and Queen Elizabeth stand near the spot where a bomb hit during a night raid on London.

Known as the Black Friday fires, the bushfires on Jan. 13 1939, in Victoria, Australia, were part of an especially devastating fire season. They followed a drought that lasted several years. About 2 million hectares were burned and 71 people died.

Confederate Gen. Nathan Bedford Forrest was born Friday, July 13, 1821 in Chapel Hill, Tennessee. Forrest served as the first grand wizard of the Ku Klux Klan.

Hundreds of the Knights Templar were arrested Friday, Oct. 13, 1307, by order of France's Philip IV. The event is sometimes credited for being the origin of the Friday the 13th superstition. However, references to the unlucky day didn't appear until hundreds of years later. 

Modern mentions of the 1307 date being the original "Friday the 13th" include Maurice Druon's historical novel "The Iron King (Le Roi de fer)" (1955),  John J. Robinson's "Born in Blood: The Lost Secrets of Freemasonry" (1989), and Dan Brown's "The Da Vinci Code" (2003).

The origin of Friday the 13th is also credited to the story of Jesus' crucifixion because he was killed on a Friday and there were 13 people at the last supper.