Monday, October 8, 2018

A Common Joke

On the face of it, being ticklish is completely pointless. Yet most people and some animals find it absolutely hilarious. However, after further research, tickling has been divided into two types: knismesis and gargalesis. Knismesis has evolved as a slightly irritating response to any movement on the skin. This response has been identified as a defense mechanism on the body's surface for animals usually against insects or parasites.

Gargalesis is a mammalian only response to stimuli on the body surface, accompanied by laughter. The tickle acts as a primal stimulus for laughter. The evolutionary history of this behavior has not yet been thoroughly mapped. However, it has been studied in apes since they have a common ancestor with humans. It was also noted that for apes to be laughing, they would have to be playing with their mates and not by just social or behavioral cues could cause laughter.

As with the chimpanzees, an ethologist, Patricia Simonet observed a laughter-like "breathy pronounced forced exhalation" which was associated with play. Recordings of it could even be used to decrease stress in other dogs. A similar observation was noted in Asian elephants too. The experiments also concluded that younger apes and mice wanted to be tickled more as their sounds were recorded and correlated to human laughing noises. Given that apes and humans split millions of years ago but still share this behavioral trait, it is easy to assume that the behavior could be as old or even older.

Though the study is not entirely conclusive, a better knowledge the topic would have many practical applications. Since his time tickling rats with his Ph.D. advisor, Jeffrey Burgdorf has used what he learned to help develop treatments for psychiatric disorders. Understanding animal happiness can also improve animal lives, especially their conditions in captivity.

Posted by Veshal Venkat


  1. I think this has a lot of potential uses for animals in captivity. Maybe in mental disorders, or people susceptible to them as well? Increased laughter might increase fitness somehow. It's easy to see how the defense response would get passed on: easy prevention of diseases spread by bugs or small animals on the skin.

    Posted by "Chandler Kupris"

  2. It is interesting how laughter is a defense mechanism; it doesn't seem to really defend from anything except stressful situations. I am curious to see where this research goes in the future and if 'tickleish' feelings are also in birds or other animal species.
    -Rachel Klett

  3. So the common form of tickling that most people probably think of is known as gargalesis. I've always wondered why we laugh when we are tickled because it seems like kind of an odd response. Personally, I hate getting tickled and yet, I still laugh every time it happens. It's this uncontrollable response or reflex. How can something be unpleasant and unfunny, yet cause me to laugh?

    -Matt Murdoch

  4. I wrote a blog post on how octopuses react to the drug ecstasy the same way as humans do. It's very interesting how animals can have the same reactions as humans do regarding so many things, such as joking, laughing, feeling happy. That sort of makes me feel happy, because they have just as much feelings as we do!

    -Han Nguyen.