System 1 and System 2
A way of describing two modes of thinking: one fast, automatic, and intuitive, and the other slow, deliberate, and effortful.
What problem it addresses
Explains why we often answer with the first thing that comes to mind, even though we could reason better if we stopped to think.
An example
A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?
The fast answer appears on its own and seems obvious. Checking it takes an effort we often do not make.
Why it happens
System 1 answers instantly with what seems obvious.
System 2 could check it, but that takes effort and it often does not kick in.
If nothing slows us down, we accept the first answer.
Applications in design
Use it like this
For frequent tasks, design for fast thinking, with clear, recognizable elements.
Avoid
Taking advantage of haste to get people to accept something they would reject if they were calm.
Don’t fall for it
In important decisions, add a pause, such as a summary or a confirmation to review.
Over 50%
What the research says
That is the share of students at Harvard, MIT, and Princeton who gave the intuitive, wrong answer (Kahneman, 2011, based on Frederick, 2005).
Debated evidence. The “two systems” are a useful simplification. Specialists debate whether they really are two separate processes (Evans and Stanovich, 2013).
Connections
Authors and works
- 2000
Keith Stanovich and Richard West
First used the names System 1 and System 2.
- 2005
Shane Frederick
Created the cognitive reflection test, which includes the bat-and-ball problem.
- 2011
Daniel Kahneman
Popularized the distinction in Thinking, Fast and Slow.
Sources
Original sources
- Stanovich, K. E., & West, R. F. (2000). Individual differences in reasoning: Implications for the rationality debate? Behavioral and Brain Sciences, 23(5), 645–665. View source: Stanovich, K. E., & West, R. F. (2000)
- Frederick, S. (2005). Cognitive reflection and decision making. Journal of Economic Perspectives, 19(4), 25–42. View source: Frederick, S. (2005)
Academic reviews
- Evans, J. St. B. T., & Stanovich, K. E. (2013). Dual-process theories of higher cognition: Advancing the debate. Perspectives on Psychological Science, 8(3), 223–241. View source: Evans, J. St. B. T., & Stanovich, K. E. (2013)
Secondary sources
- Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux.
Last reviewed: