Like in Influence: The Psychology of Persuasion Dr. Robert B. Cialdini breaks down the psychology behind why people say “yes.” There are six universal principles behind persuasion: 1. Reciprocity – pay back what we receive 2. Scarcity – people want what they can't have 3. Authority – people follow credible experts 4. Consistency – consistency with past actions 5. Liking – people say "yes" to things they like 6. Consensus – looking for what others have done
