Socrates wondered 2,000 years ago, and Charles Darwin also racked his brains: what is a tickle, and why are we so sensitive to tickling? ‘Tickling is relatively under-researched,’ says neuroscientist ...

The Sundance documentary Tickled — summarized with the logline “a New Zealand reporter accidentally stumbles upon an underground competitive tickling contest” — sounded like a barrel of laughs. But ...