Clicker

• In World War II clickers were used by Allied paratroopers preceding and during Operation Overlord as a way of covertly identifying friend from foe. A soldier would click once and if two clicks were received in return from an unidentifiable soldier then his identification was confirmed. • Clickers are used to provide audible feedback for human students learning using a method called TAGteach. • Clickers were used to organize Catholic group activity. "The clickers were dime store crickets that made a nice, loud click, perfect for signaling a First Communion class so all the kids would stand up at the same time, and kneel at the same time, and start filing down the aisle together." — Roger Ebert

Clickers were first used by marine mammal trainer Karen Pryor as a way of communicating with her animals. Dolphins and whales communicate underwater through a series of clicks and whistles known as echolocation, and the clicker allowed a trainer to produce signals they were more likely to understand. Clickers are now used to train dogs, and other animals. When associated with a treat, a click allows the owner to mark the precise moment the desired behavior is executed.

• countingClickers are also used as a handheld counting device, sometimes digital but more commonly mechanical, used to keep a count of the numbers of people entering a venue. It is often used by nightclub doorstaff to make sure fire limits are not exceeded. • A clicker is a device used on recurve bows to signal to the archer that correct draw length has been achieved, thus aiding consistency. • Some board games designed after game shows come with clickers that are meant to emulate the buzzers common on such shows. • Clickers are used by some kink practitioners, in particular in the context of pet play.