This chapter explores the foundational theories and models that shaped cognitive psychology, tracing its evolution from early philosophical inquiries to modern computational approaches. It begins with structuralism and functionalism, which seek to deconstruct and understand mental processes, followed by associationism, which emphasizes the role of learned connections between ideas. The discussion then moves to Gestalt psychology, which revolutionized the understanding of perception by highlighting how humans process information holistically rather than as isolated components. The rise of the information processing approach in the mid-twentieth century marked a paradigm shift, likening cognition to computational processes involving encoding, storage, and retrieval. Influential figures such as Miller, Broadbent, Baddeley, and Atkinson & Shiffrin contributed critical models that refined our understanding of memory, attention, and decision-making. The chapter also examines connectionism and neural networks, which emphasize parallel distributed processing and learning algorithms as key mechanisms in cognitive function. The contributions of AI pioneers, including McCulloch, Pitts, Minsky, and Newell, are highlighted, revealing the intersection between cognitive science and artificial intelligence. By synthesizing these perspectives, this chapter lays the groundwork for understanding cognition as an adaptive, complex system influenced by both biological and technological advancements.