The premise of behavioral finance is that conventional financial theory should ignore how the average person makes decisions because the market is driven by investors that are much more sophisticated than the average person conventional financial theory ignores how real people make decisions and that people make a difference conventional financial theory considers how emotional people make decisions but the market is driven by rational utility maximizing investors conventional financial theory considers how emotional people make decisions but the market is driven by rational utility maximizing investors AND conventional financial theory should ignore how the average person makes decisions because the market is driven by investors that are much more sophisticated than the average person