Influence Explores The Psychology Behind Consumer Decisions: Robert Cialdini’s Influence: The Psychology of Persuasion remains a popular recommendation for marketers in 2026 because it examines the psychological principles behind persuasion. Its updated edition covers principles including reciprocity, commitment, social proof, authority, liking, scarcity and unity. Understanding these behavioural patterns can help marketers create clearer messaging, stronger offers and more persuasive customer experiences.