The ethics of mass marketing are dubious and tricky.
It's no wonder that our scientific duo ends up splitting in the end. Look at the gravity of their discoveries. On one hand, a public of such a large population demands serious, scientific efforts for effective marketing, but on the other hand, the principles outlined in the book can be used to brainwash unwilling victims. So the science is neither good nor bad, it's only the use of the tool that can be positive or negative. The scientific truth of our brain is that we are not as in control of our beliefs as we think we are.
The market can use psychology for marketing and advertisement purposes.
Here's one example of this: By being exposed to a word or idea over and over, the brain starts to associate importance with those concepts that repeat. So, if for instance, you were running for president, normal intuition would say "Try to toe the line. Try to do everything perfectly," but a little bit of behavioral psychology would re-inform that idea. Instead of trying to say the right thing, say the controversial thing—the attention will make people polarize, and you'll win the race, not by saying the right thing, but by consistently saying the wrong things. This is explained in the book. We are easily influenced by repetition, so people feel more important the more we see them. If the purpose of an advertising campaign is to increase the power of a brand, this is one of the fundamental things the brand needs to do.
We are not in control of our beliefs.
As mentioned above, the main irony of this whole endeavor is that people often misunderstand their own motivations, and without fail, people tend to believe they have more power over their beliefs than they do.
