Applies behavioural science to marketing decisions using only effects with solid published evidence, named as the research literature names them, with their replication record. Use when someone asks about "marketing psychology", "cognitive biases", "persuasion", "why people buy", "behavioural science", "nudges", or wants to use anchoring, scarcity, social proof, defaults, loss aversion or a decoy on a pricing page, checkout, signup or upgrade prompt. Grades each effect, says where it failed to replicate, checks the idea against consumer-protection rules, and turns it into a sized experiment.
