I’ve always found the act of “tickling” in itself to be quite absurd. We touch someone repeatedly in a sensitive area (whether it be under the arm or on the sole of the foot) and as a result, we cannot help but laugh hysterically. But what really baffles me, is that this assumption doesn’t hold true when we try to tickle ourselves. This discrepancy made me wonder if laughing is actually a reflex of tickling or if there is a social factor involved.

Before conducting any research on the subject, I assumed that tickling caused a pleasant sensation. Why else would our reaction be to laugh and smile, two telltale signs of happiness? Multiple sites led me to this same hypothesis, which we refer to as the  “Darwin/Hecker Hypothesis of laughter/humor.” Created by biologist Charles Darwin and psychologist Ewald Hecker in the 1800’s, their theory assumes that laughter (induced by tickling) requires a good mood and ultimately is a pleasant sensation. For years this theory faced little objection or experimentation to prove its legitimacy, but a study done in the late 1990’s showed that their theory might be old-fashioned.

An undergraduate student Christine Harris and  researcher Dr. Nicholas Christenfeld of University of California at San Diego took it upon themselves to test out Darwin and Hecker’s hypothesis. To do this, Harris and Christenfeld adopted 72 undergraduate students to participate in their study. The study was based off of what they called the “warm-up effect,” which assumes that when someone finds something funny, being exposed to humor after that will seem even funnier. To test this, one group was tickled until the point that it was unbearable and then shown a series of comedy scenes such as clips from “Saturday Night Live.” The other group completed this in reverse, so, they watched the clips and then were tickled. The control group watched a video that was supposedly unfunny and then was tickled. What the researchers believed would prove Darwin and Hecker’s hypothesis was that being exposed to either the tickling or the comedic clips would make the other one more funny, according to the warm-up theory. What they found was that neither had any effect on the amount of laughter that the groups produced, which went against their theory and implied that tickling does not cause happiness or pleasant feelings. If this experiment was done correctly, then does that mean that tickling has no emotional connection, but is just a reflex?

Harris and Christenfeld decided to follow up on that hypothesis with another experiment. This included 32 undergraduate students this time, who believed that they would be tickled by a human and a machine, each for 5 seconds. This was a double-blind placebo trial because despite their belief that two different mechanisms would be doing the tickling, they were actually tickled by two humans. The results of the experiment showed that despite their lack of knowledge on the “tickler,” the students laughed and smiled just as much. In effect, they concluded that tickling was a mere reflex similar to “the one a doctor elicits from a patient’s knee with a little rubber hammer.” (Yoon, “Anatomy of a Tickle”)

Neither experiments completely convinced me that laughter is a reflex of a tickling because we still cannot tickle ourselves.There were many loopholes in Harris and Christenfeld’s first experiment such as their ability to measure laughter, different senses of humor, and possible resistance to a reaction from tickling. Their second experiment was more concrete, but the lack of experimentation done on this subject in general makes it hard to assume something as correct. But if I have learned anything from the research I’ve done on the subject, it is that tickling is nothing to laugh about.

Sources:

• Yoon, Carol K. “Anatomy of a Tickle Serious Busiess at the Research Lab.” The New York Times. The New York Times Company, 3 June 1997. Web. <http%3A%2F%2Fwww.nytimes.com%2F1997%2F06%2F03%2Fscience%2Fanatomy-of-a-tickle-is-serious-business-at-the-research-lab.html>.
• Clark, Josh. “Why Do People Laugh When They Get Tickled?” HowStuffWorks. HowStuffWorks.com, n.d. Web. 02 Oct. 2014. <http://science.howstuffworks.com/life/inside-the-mind/emotions/laugh-tickling2.htm>.
• “UCSD Psychologists Tackle Ticklish Subject.” Newswise. Newswise, Inc., n.d. Web. 02 Oct. 2014. <http://www.newswise.com/articles/ucsd-psychologists-tackle-ticklish-subject>.