This document discusses leveraging principles of psychology to inform SEO decisions. It outlines different systems of thinking - system 1 involves intuition and instinct while system 2 involves rational, logical thinking. It then covers various psychological concepts like the anchoring effect, reciprocity, scarcity, authority, consistency, consensus, and framing effect that can be used to influence behavior. Specific tactics are provided like using different tones of voice, mirroring, visualizing data, and creating checklists to overcome biases and make more informed decisions.