Neuroscientist Antonio Damasio studied people who had received brain injuries that had had one specific effect: to damage that part of the brain where emotions are generated. In all other respects they seemed normal - they just lost the ability to feel emotions.
The interesting thing he found was that their ability to make decisions was seriously impaired. They could logically describe what they should be doing, in practice they found it very difficult to make decisions about where to live, what to eat, etc.
In particular, many decisions have pros and cons on both sides. Shall I have the fish or the beef? With no rational way to decide, they were unable to make the decision.
Knowing this, we must first trigger emotions in people in order to persuade them.
We Trigger Emotion by understanding some basic psychology like...