Reverse psychology was a psychological technique by which one person persuaded another to support their position on an issue by advocating its opposite. This was done in such a way as to make the other person see the flaws in the opposing view that they might not have seen had the person only advocated the benefits of their view.
In 2366, following Ard'rian McKenzie's suggestion, Data employed reverse psychology in an attempt to convince Gosheven, the leader of an illegal colony on Tau Cygna V, to evacuate due to the arrival of the planet's owners, the Sheliak. Data did so after previous attempts to simply use the merits of evacuation to persuade Gosheven failed. While he was able to persuade some colonists to leave, Gosheven did not change his mind. It took a demonstration of what the Sheliak might do to the colony to finally win Gosheven over. (TNG: "The Ensigns of Command")