Are we programmed to laugh when tickled?

Parenting

Do you learn to laugh when you tickle it or is it an innate response?
This is the question that the psychologist, Professor Clarence Leuba, asked himself to examine using his own children, no less, as experimental subjects.
In 1933, he decided not to laugh in the presence of his first child by tickling him.
Everyday life in the Leuba house was therefore free of tingling, except during a special experimental period.
During this period, he would cover his own face with a mask by tapping his son so that his facial expression was hidden.
Even the tickling has been controlled experimentally.
First, it tickled slightly, then more vigorously.
First under the armpit, then the ribs, followed by the chin, neck, knees and feet.

Mrs. Leuba slips

Everything seems to have gone well until the end of April 1933, when his wife suddenly forgot all the protocols.
After the bath of her son, she accidentally administered a brief jump up and down on her knee while laughing while using the words: “Bouncy, bouncy”!
Has the experience been ruined?
Leuba was not sure.
But after seven months, with a single laugh associated with splashing, the results were there.
Her son laughed happily when he was tickled.
It appeared that laughing when tickled was an innate response.
Leuba was not satisfied with this, however, and began to perform the same test on her next child, a girl.
This time, the same experimental procedure was administered and Ms. Leuba's “Bouncy, bouncy” trends were apparently kept at bay for seven months.
In the end, Leuba achieved the same results – her daughter started laughing spontaneously when she was tickled although she was never shown.

Tips for tickling

But these were not all experimental procedures and hidden faces in the Leuba house, indeed, Professor Leuba must have become an expert tickler.
He found that the best way to make his children laugh was to tickle them along the ribs and under the arms.
The element of surprise also played an important role in producing maximum response.
He observed that his children would control the level of tickling by holding his finger, but would then demand more tickling.

Reference
Leuba, C. (1941) Tickling and laughter: two genetic studies. Journalof Genetic Psychology.