dualprocess

Dual-process theory is a framework in cognitive science that posits two distinct systems for processing information. System 1 is fast, automatic, implicit, and operates with little or no conscious control. It relies on learned heuristics and associations to produce quick judgments and impressions. System 2 is slower, deliberate, explicit, and effortful; it involves reasoning, planning, and self-monitoring, and it can override System 1 when necessary.

The theory emerged from research in the late 20th century, with early work by Kahneman and Tversky on how heuristics can lead to systematic errors in judgment, and later popularization by Kahneman in Thinking, Fast and Slow. In typical tasks, System 1 generates initial responses; System 2 evaluates and may correct them, though System 2 is resource-intensive and prone to cognitive load or motivational constraints. People often rely on System 1 under time pressure, stress, or distraction, whereas System 2 can be engaged for complex inference, calculation, or unfamiliar problems.

Applications span many domains, including economic decision making, consumer behavior, education, and medicine. The framework helps explain phenomena such as biases, framing effects, and the distinction between intuitive versus analytical thinking. It has also influenced models of rationality and artificial intelligence.

Critics argue that the dichotomy can be overstated, with many processes not neatly assigned to one system or another, and that neurological evidence shows more integrated networks. Some researchers advocate a gradient or process-based account rather than two discrete systems.