When they were «caught,» they were given a series of mild electric shocks. (discovermagazine.com)
In their experiment, participants were repeatedly shown a blue square while receiving mild electric shocks on the wrist, and learned to associate the two stimuli, so that afterwards they responded to the square with fear. (scientificamerican.com)
Then, when researchers left people alone in a room with a device that let them jolt themselves with mild electric shocks, they discovered that most men are so desperate for distractions that they would rather zap themselves. (discovermagazine.com)