System 1 Automatic Brain

Our System 1 Intuitive Brain, as described by Daniel Kahneman, is generally our unconscious and uncontrollable attention such as reacting to a loud noise, catching yourself when you're off balance, or social situational awareness. But sometimes System 1 can be controlled such as chewing or breathing.

System 1, the intuitive brain, uses Heuristics and Biases to make very efficient decisions, but these have flaws. System 1 passes information about the world to System 2 Effortful Brain in the form of impressions and desires and this is generally fine. However, the relationship between these two sides of our mind means We are Prone to Errors in Intuitive Reasoning