System 1 refers to the fast, automatic, and intuitive way our brain processes information. It operates quickly and effortlessly, allowing us to make snap judgments and decisions without deep analysis. This system is responsible for our immediate reactions, such as recognizing a friend's face or feeling fear when we see a snake. In contrast to System 2, which is slower and more deliberate, System 1 relies on heuristics and mental shortcuts. While this can be efficient, it may also lead to biases and errors in thinking, as it often overlooks details and complexities in situations.