Humans laughed before they spoke
Some scientists believe that laughter was used as a way for humans to relate to one another millions of years before they developed the lung strength for language. The mechanism of laughter is so ingrained in our brains that babies as young as 17 days old have been observed doing it. In fact, children born blind and deaf still have the ability to laugh. (This is the psychological reason you laugh at the worst times.)
Laughter is actually rarely tied to humor
In his book, Laughing: A Scientific Investigation, Robert R. Provine, professor of psychology and neuroscience at the University of Maryland, Baltimore, describes an intriguing study about laughter—and it didn't take place at a comedy club. Provine and some graduate students listened in on normal conversations at local malls. They found that out of 1,200 "laugh episodes," only about 10 percent were generated by a joke. "Laughter really has a bonding function between individuals in a group," says Provine. (If you laugh at these dark jokes you're probably a genius.)
Rats and monkeys laugh
It may sound strange, but several scientists have elicited "tickle-induced vocalizations" from primates. Penny Paterson, president of the Gorilla Foundation says that Koko, the gorilla famous for her sign language abilities, even had a special "ho, ho," for visitors she liked. And rats apparently have very ticklish necks. When Bowling Green State University scientist Jaak Panksepp and his graduate students tickled baby rats' napes, the rodents emitted high-frequency chirps that Panksepp interpreted as laughter.
Couples who laugh together, stay together
Robert Levinson, psychology professor at the University of California Berkeley, invited couples into his lab and asked each partner to discuss something that irritated him or her about the other partner. The couples who tackled the stressful situation with laughter not only felt better in the moment, but had higher levels of relationship satisfaction and stayed together longer than couples who didn't crack a smile. (This is the science behind why having the same sense of humor as your spouse strengthens your relationship.)
Laughter controls our brains
When you see people laughing, you just can't help but smile, right? That's because your brain makes it nearly impossible not it. That's the result of research from the lab of Sophie Scott, a neuroscientist at University College London. When she monitored subjects' brains while she played laughing sounds, she found that the premotor cortical region of the brain, which prepares the muscles in the face to move, was activated.
Laughing burns more calories than you may think
No joke! Just 10 to 15 minutes of laughing a day can burn up to 40 calories, according to a Vanderbilt University study. Researchers determined that the increase in heart rate and oxygen consumption during these funny moments boosted the burn. (This is how keeping a laughter journal can change your life.)
Nashville is a really funny place
At 8:04 p.m. on April 15, 2015, a crew of comedians put Nashville in the record books. Funny folks including Hannibal Buress, Rory Shovel, and Ahmed Ahmed riffed on stage to help set a new record for the longest continuous stand-up comedy show by multiple comedians: 208 hours, 16 minutes.
Laughter really is the best medicine
Study after study has pointed to the health benefits of laughter: Research from Loma Linda University showed that laughing improved the memory of adults in their 60s and 70s; University of Maryland School of Medicine researchers found that hilarious movies improved the function of blood vessels and increased blood flow in a group of 20 thirty-somethings. And other research has shown that laughing can improve immunity, help regulate blood sugar levels, and improve sleep.
Your sense of humor might be genetic
In a Northwestern University study of more than 300 people, those with the short version, or allele, of gene 5-HTTLPR are quicker to laugh at cartoons or funny movie clips than those with the long version of the gene. That particular gene has long been associated with the study of depression, but this is the first study to look at its connection to positive emotions. "People with short alleles may flourish in a positive environment and suffer in a negative one," said study co-author Claudia M. Haase. "While people with long alleles are less sensitive to environmental conditions." (You can actually have a phobia of laughter. This is the science behind why some people can't take a joke.)