Remember having knock-down-drag-out tickle fights as a kid? At the time, they seemed like a normal part of play. But for most adults, the thought of being tickled is annoying at best. And yet, it’s ...

In a grey-walled room in the Dutch city of Nijmegen, a strange activity is underfoot. Wearing a cap covered in sensors and positioning themselves into a chair, a person places their bare feet over two ...