One thing we know about tickling: It makes us laugh. But why? And what exactly is it? Is it pain? Pleasure? Aristotle wrote about tickling all the way back in 350 B.C. Darwin did too, in 1872. But, of ...

The mere mention of the word “tickle” can elicit a variety of reactions. For one person, tickling can represent play, while it can be the source of a sexual response for another, and for some, it has ...