Part 1
Two Systems
Our brain has two fundamentally different modes of thinking. System 1 is fast, automatic, and intuitive; System 2 is slow, rational, and effortful. Understanding how these two systems work is key to understanding human decision-making.
System 1
System 1 operates fast and automatically, requiring minimal conscious control and almost no mental effort. It is responsible for:
- •Recognizing facial expressions and emotions
- •Understanding simple sentences
- •Driving on an empty road
- •Making first impressions
System 2
System 2 operates slowly and rationally, requiring conscious thought and control. It is responsible for:
- •Solving complex math problems
- •Comparing cost-effectiveness of different products
- •Parking in a crowded lot
- •Checking the validity of logical arguments
Trap
Bat and Ball
System 1 operates automatically and quickly, with little or no effort and no sense of voluntary control. It is prone to biases and systematic errors.
Try this classic puzzle. Answer as quickly as you can.
A bat and a ball cost $1.10 in total.
The bat costs $1.00 more than the ball.
How much does the ball cost?
Conflict
Stroop Effect
Your System 1 wants to read the word because reading is automatic. Your System 2 must work to suppress this impulse and say the color.
Task: Say the color of the word, not the word itself.
Key Insights
System 1 Cannot Be Turned Off
We cannot stop System 1's automatic reactions. Even when we know an intuitive answer is wrong, it still appears in our mind first.
System 2 is Lazy
System 2 requires substantial cognitive resources and energy. To conserve energy, our brain relies on System 1 as much as possible, only invoking System 2 when necessary.
Conflict and Cooperation
The two systems usually work together, but sometimes conflict. When System 1 provides a wrong intuitive answer, we need System 2 to correct it—but this requires us to actively engage System 2.