The stocks are considerably older than that. Western Europe saw their use as early as the Roman Republic (509BC-27BC) and more so during the Imperium. Asia, primarily East Asia, saw a device similar to them around the same time span. There isn't too much to them. It's a seat, a board with holes cut in them, and a lock. They served originally as a form of jail (jails and prisons aren't, in the grand scheme of things, very old at all). It kept a prisoner in place and bound, which was also used later in Europe (and the Americas) as a way to keep slaves from fleeing captivity. They evolved into a means of public punishment, and yes, tickling was used in this capacity. This also makes perfect sense (immobile bare feet sticking out of a board, belonging to someone who can't get free or stop me, mwuhahaha), but this is by no means their reason for creation.The stocks are designed rather well for the tickling of the feet (that is to my understanding what they actually were invented for some 500 years ago). Any history buffs with more info please bring it on!