---
title: The Mueller-Lyer Illusion
created: 2025-01-23T10:40:57
modified: 2025-07-16T21:23:31
---

= Cognitive Illusion by Daniel Kahneman

System 1 is instinctive and emotional.

System 2 is conscious and logical.

System 1 says that the bottom line is longer than the top line. After measuring them, you are convinced by your System 2 understanding that they are, in fact, of equal length. But System 1 sticks to the illusion and continues to “see” that the bottom line is longer.

![66302eb59a26100c50316b225457a5ee](../_attachments/66302eb59a26100c50316b225457a5ee.png)