Inside a Berlin neuroscience lab one day last year, Subject 1 sat on a chair with their arms up and their bare toes pointed down. Hiding behind them, with full access to the soles of their feet, was ...

I was surprised the first time I saw someone transform into a tickle monster. They curled up their fingers and rhythmically poked someone else’s armpits. I asked my friend John Wright about it. He’s a ...