The Study of Laughter

Paragraph 1

Humans don't have a monopoly on laughter, says Silvia Cardoso. A behavioral biologist at the State University of Campinas, Brazil, she says it's a primitive reflex common to most animals; even rats laugh. She believes that too little laughter could have serious consequences for our mental, physical and social well-being.

Paragraph 2

Laughter is a universal phenomenon, and one of the most common things we do. We laugh many times a day, for many different reasons, but rarely think about it, and rarely consciously control it. We know so little about the different kinds and functions of laughter, and our interest really starts there. Why do we do it? What can laughter teach us about our positive emotions and social behavior? There's so much we don't know about how the brain contributes to emotion and many scientists think we can get at understanding this by studying laughter.

Paragraph 3

Only 10 or 20 percent of laughing is a response to humor. Most of the time, it's a message we send to other people, communicating joyful disposition, a willingness to bond and so on. It occupies a special place in social interaction and is a fascinating feature of our biology, with motor, emotional and cognitive components. Scientists study all kinds of emotions and behavior, but few focuses in this most basic ingredient. Laughter gives us a clue that we have powerful systems in our brain that respond to pleasure, happiness and joy. It's also involved in events such as release of fear.

Paragraph 4

Many professionals have always focused on emotional behavior. Researchers spent many years investigating the neural basis of fear in rats, and came to laughter via that route. It is noticed that when they were alone, in an exposed environment, they were scared and quite uncomfortable. Back in a cage with others, they seemed much happier. It looked as if they played with one another real rough and tumble, and researchers wondered whether they were also laughing. The neurobiologist Jaak Panksepp had shown that juvenile rats make short vocalizations, pitched too high for humans to hear, during rough-and-tumble play. He thinks these are similar to laughter. This makes us wonder about the roots of laughter.

Paragraph 5

We only have to look at the primate closest to humans to see that laughter is clearly not unique to us. This is not too surprising, because humans are only one among many social species and there's no reason why we should have a monopoly on laughter as a social tool. The great apes, such as chimpanzees, do something similar to humans. They open their mouths wide, expose their teeth, retract the corners of their lips, and make loud and repetitive vocalizations in situations that tend to evoke human laughter, like when playing with one another or with humans, or when tickled. Laughter may even have evolved long before primates. We know that dogs at play have strange patterns of exhalation that differ from other sounds made during passive aggressive or confrontation.

Paragraph 6

But we need to be careful about over-interpreting panting behavior in animals at play. It's nice to think of it as homologous to human laughter, but it could just be something similar but with entirely different purposes and evolutionary advantages. Everything humans do has a function, and laughing is no exception. Its function is surely communication. We need to build social structures in order to live well in our society and evolution has selected laughter as a useful device for promoting social communication. In other words, it must have a survival advantage for the species.

Paragraph 7

The brain scans are usually done while people are responding to humorous material. Brainwave activity spreads from the sensory processing area of ​​the occipital lobe, the bit at the back of the brain that processes visual signals, to the brain's frontal lobe. It seems that the frontal lobe is involved in overlooked things as funny. The left side of the frontal lobe analyzes the words and structure of jokes while the right side does the intellectual analyzes required to “get” jokes. Finally, activity spreads to the motor areas of the brain controlling the physical task of laughing. Researchers also found out that these complex pathways involved in laughter from neurological illness and injury. Sometimes after brain damage, tumors, stroke or brain disorders such as Parkinson's disease, people get “stonefaced” syndrome and can't laugh.

Paragraph 8

We are sure that laughter should differ between the sexes, especially the uses to which the sexes put laughter as a social tool. For instance, women smile more than laugh, and are particularly adept at smiling and laughing with men as a kind of “social lubricant”. It might even be possible that this has a biological origin, because women don't or can't use their physical size as a threat, which men do, even if unconsciously.

Paragraph 9

Laughter is believed to be one of the best medicines. For one thing, it's exercise. It activates the cardiovascular system, so heart rate and blood pressure increase, then the arteries dilate, causing blood pressure to fall again. Repeated short, strong contractions of the chest muscles, diaphragm and abdomen increase blood flow into our internal organs, and forced respiration –the ha! ha! –making sure that this blood is well oxygenated. Muscle tension reduces, and indeed we may temporarily lose control of our limbs, as in the expression “weak with laughter”. It may also release brain endorphins, reducing sensitivity to pain and boosting endurance and pleasurable sensations. Some studies suggest that laughter affects the immune system by reducing the production of hormones associated with stress, and what when you laugh the immune system produces more T-cells. But no rigorously controlled studies have confirmed these effects. Laughter's social role is definitely important.

Paragraph 10

Today's children may be heading for a whole lot of social ills because their play and leisure time is so isolated and they lose out on lots of chances for laughter. When children stare at computer screens, rather than laugh with each other, this is at odds with what's natural for them. Natural social behavior in children is playful behavior, and in such situations laughter indicates that make-believe aggression is just fun, not for real, and this is an important way in which children from positive emotional bonds, gain new social skills and generally start to move from childhood to adulthood. Parents need to be very careful to ensure that their children play in groups, with both peers and adults, and laugh more.