Everyone knows about Pavlov's theory don't they? Triggers for...

Everyone knows about Pavlov's theory don't they? Triggers for horses are an extension of that.

Pavlov called the dogs' anticipatory salivation "psychic secretion". Putting these informal observations to an experimental test, Pavlov presented a stimulus (e.g. the sound of a metronome) and then gave the dog food; after a few repetitions, the dogs started to salivate in response to the stimulus.