Behavioral marketing

People do not evaluate offers on merit and then act. They decide fast, under uncertainty, using whatever the context makes salient — and then explain the decision afterward. Marketing that assumes otherwise loses to marketing that does not.

The effects that most often explain a stuck conversion

Reference dependence. Nothing is judged absolutely. A price is high or low relative to whatever was shown first, so what you present first sets the frame for everything after it.

Loss aversion. Losing something registers considerably more than gaining the equivalent. This is why switching costs are underestimated by sellers and overestimated by buyers, and why "what you are currently losing" often outperforms "what you could gain."

Choice overload. More options reduce the likelihood of any choice being made. Beyond a small number, each additional option raises the cost of deciding faster than it raises the chance of a good match. If a pricing page has seven tiers, the problem is not the copy.