Behavioral Economics
The Systems 1 and 2 construct of Daniel Kahneman help to explain the observed patterns of effect of emotional and rational campaigns. Emotional campaigns work through (automatic) System 1 whereas rational campaigns must attempt to engage the reluctant System 2.
Because System 1 effects operate below the radar, they do not rely solely on conscious, rational response in research. Remember that the emotional effects that matter most in the long term are mainly non-verbal and unconscious.
"Some purchases are carefully considered, while others are done on autopilot. Some purchases are strongly driven by feelings and emotion, while information plays a stronger role in others. The nature of the purchase decision has a strong influence on how marketing works" — Effectiveness in Context
"It is fashionable to talk about the changing man. A communicator must be concerned with the unchanging man—what compulsions drive him, what instincts dominate his every action, even though his language too often camouflages what really motivates him" — Bill Bernbach