This white paper looks at how cognitive science, specifically attention, memory, decision-making, trust, and emotion, shapes the way consumers behave and what that means for marketers. The paper draws on well-known behavioral research to make its case. It covers principles such as the Invisible Gorilla study on inattentional blindness, the Serial Position Effect, the Von Restorff Effect, Iyengar and Lepper's jam study on choice overload, research on thin-slice judgments and first impressions, and the Iowa Gambling Task. The unifying framework is Daniel Kahneman's dual-system theory: most consumer decisions are driven by fast, intuitive, emotional thinking (System 1) rather than slow, deliberate reasoning (System 2). Each of the five principles comes with practical marketing guidance, from how to structure a list of benefits to how many product options to offer to how to build trust in the first few seconds of contact. The paper closes by framing cognitive science as a way to move beyond describing what consumers do and start predicting why they do it, which is the basis for more effective, targeted marketing strategy.