1. Getting something extra “for free” feels better than getting the same for less.
  2. We’re heavily influenced by the first number.
  3. We’re terrified of extremes.
  4. We’re in love with stories.
  5. We do what we’re told.
  6. We let our emotions get the best of us.
  7. We’re easily made dumber by alcohol, time, decisions.
  8. We’re pained by transaction costs…
  9. … but we’re weird about rebates and warranties.
  10. We’re obsessed with the number 9.
  11. We’re compelled by a strong sense of fairness.

What’s a poetry recital by a behavioral economist worth? The students had no idea. That’s the point. I don’t know, either. That’s also the point. What’s a button-up shirt “worth”? What’s a cup of coffee “worth”? What’s a life insurance policy “worth”? Who knows! Most of us don’t. As a result, the shopping brain uses only what is knowable: visual clues, triggered emotions, comparisons, ratios, and a sense of bargain vs. rip-off. We’re not stupid. Just susceptible.