Biases in Thinking and Decision-Making — Dual-Process Theory

Human beings like to believe they are rational, weighing evidence carefully before reaching conclusions. In reality, much of our thinking relies on mental shortcuts that are fast and usually useful but can lead to systematic errors. The most influential framework for understanding this is dual-process theory, popularized by Daniel Kahneman in his account of two modes of thought, often called System 1 and System 2. This work grew out of decades of research he conducted with Amos Tversky on judgment and decision-making under uncertainty.

System 1 is fast, automatic, intuitive, and effortless. It operates constantly in the background, generating impressions and feelings without conscious control. When you instantly recognize a friend's face, react to a sudden noise, or sense that a sentence s