What is the Evolutionary Purpose of Tickling?

' You probably know that you can’t tickle yourself. And although you might be able to tickle a total stranger, your brain strongly discourages you from doing something so socially awkward.
These facts offer insight into tickling’s evolutionary purpose, says Robert R. Provine, a neuroscientist at the University of Maryland and the author of the book.

Tickling, he says, is a mechanism for social bonding between close companions, helping to forge relationships between family members and friends. Laughter in response to tickling kicks in during the first few months of life. “It’s one of the first forms of communication between babies and their caregivers,” Provine says. Parents learn to tickle a baby only as long as she laughs in response. When the baby starts fussing instead, they stop. The face-to-face activity also opens the door for other interactions. Children enthusiastically tickle each other, which some scientists say not only inspires peer bonding but also might hone reflexes and self-defense skills. In 1984, psychiatrist Donald Black of the University of Iowa noted that many ticklish parts of the body, such as the neck and the ribs, are also the most vulnerable in combat. He inferred that children learn to protect those parts during tickle fights, a relatively safe activity.

Tickling while horsing around also may have given rise to laughter itself. “The ‘ha ha’ of human laughter almost certainly evolved from the ‘pant pant’ of rough-andtumble human play,” says Provine, who bases that conclusion on observations of panting in apes that tickle each other, such as chimpanzees and orangutans. In adulthood, our response to tickling trails off around the age of 40. At that point, the fun stops; for reasons unknown, tickling seems to be mainly for the young.

Comments

How Will the Universe End?

In 1929, Edwin Hubble discovered that the universe is not in fact static, but expanding. In the years following his discovery, cosmologists took up the implications of the discovery, asking how long the universe had been expanding, what forces caused the expansion, and whether it will ever cease. Cosmologists are pretty confident about the first question: just shy of 14 billion years. A great deal of evidence supports the predominant answer to the second question: The universe rapidly emerged from a singularity in an event that cosmologists call the Big Bang. The third question is a bit more mysterious, and the answer relies on an obscure, confounding phenomenon known as dark energy. The density of dark energy in the universe determines its ultimate fate. In one scenario, the universe does not possess enough dark energy to forever counteract its own gravity and thus ends in a “Big Crunch.” Under this scenario, the universe’s gravity will overcome its expansio...

What Causes Volcanic Lightning?

On March 10, 2010, Eyjafjallajökull volcano, a caldera in Iceland covered by an ice cap, erupted. It sent plumes of clouds across most of Europe and the Atlantic Ocean. Photos of the eruption show lightning originating and ending in the cloud of ash that hovered over the volcanic opening. The largest volcanic storms are similar to supercell thunderstorms that spread across the American Midwest. But while those thunderstorms are fairly well understood, volcanic lightning still remains mysterious. The remote location of volcanoes and infrequent eruptions make volcanic lightning difficult to study. In general, lightning occurs through the separation of positively and negatively charged particles. Differences in the aerodynamics of the particles separate the positive and negative. When the difference in charge is great, electrons flow between the positive and negative regions. A lightning bolt is a natural way of correcting the charge distributi...

Why Do We Have Fingerprints?

Many scientists once thought fingerprints help us hold onto objects. From an evolutionary perspective, getting a better grip on tools or weapons would have made life easier for early humans. In 2009, Dr. Roland Ennos of Manchester University designed an experiment that tested the gripping power of our fingerprints. He used a machine equipped with weights to pull strips of Perspex, a kind of acrylic, across a subject’s fingertips. The machine measured the amount of friction created as the acrylic passed over the tip. In the real world, a high amount of friction between two solid objects in contact with each other would indicate a better grip. In the experiment, the fingertips created some friction on the acrylic, but not as much as Ennos had expected. Ennos compares our fingerprints to the tires on a race car. Ridges in the tire reduce the surface area of the tire in contact with the road, which reduces friction. The ridges on fingertips have the ...

knowledge

Search This Blog