Clicker with wrist band.

What is Clicker Training?
History of Clicker Training.
  Clicker training is an operant conditioning method for training an animal using a clicker, or small mechanical noisemaker, as a marker for behavior.
The method uses positive reinforcement - it is reward based. The clicker is used during the acquisition phase of training a new behavior, to allow the animal to rapidly identify that a behavior is sought and also the precise behavior of interest.

Clicker training was originated through Marian Bailey(neé Kruse) and Keller Breland, who as graduate students of psychologist and eminent behaviourist B.F.Skinner taught wild-caught pigeons to "bowl" (push a ball with their beaks) while participating in military research. According to their work, animal training was being needlessly hindered because traditional methods of praise and reward did not inform the animal of success with enough promptness and precision to create the required cognitive connections for speedy learning. Similar methods were later used in training at least 140 species including whales, bears, lions and domestic dogs and cats, and even humans.

For training purposes once the behavior is sufficiently reliable on use of the clicker, a cue (e.g. a verbal command such as "sit," or "down") is added to the click, and as the response transfers to the new cue, the clicker is no longer needed (e.g. Stimulus control is attained). A clicker is just one example of a conditioned reinforcer (secondary reinforcer) or "bridge". Technically a stimulus from any sensory mode may become a conditioned reinforcer (ex. light, smells). (1)

Since the 1950s, clicker training (or more appropriately "click-and-treat" training) has grown popular with animal trainers across a spectrum of species, from dolphins to horses. The main reason for this is that clicker training is humane, compared to earlier methods.
Prior to the clicker training concept, animals were trained primarily through a combination of negative and positive reinforcement. In other words, an animal was punished, often with pain, for not performing in a desired way. If an animal did the trick or performed a behavior to satisfaction, he was rewarded with food, praise or the absence of punishment.

During World War II, this "punishment" method appeared to be the fastest way to teach animals to perform for the war effort. After the war, army trained "behaviorists" and animal trainers carried the practice over to civilian life.(2)






(1) source: Wikipedia (2) source: Petplace