Neoclassical theories in economics focus on the idea that individuals make rational choices to maximize their utility or satisfaction. These theories emphasize the role of supply and demand in determining prices and resource allocation in markets. Key concepts include marginal utility, which refers to the additional satisfaction gained from consuming one more unit of a good, and the idea of perfect competition, where many buyers and sellers exist. The neoclassical approach emerged in the late 19th century, building on earlier ideas from classical economists like Adam Smith and David Ricardo. It has influenced various fields, including microeconomics and macroeconomics, and remains a foundational framework in economic analysis today.