Comment by hoppp

The difference in humans is consciousness. System 1 is subconscious and fast, system 2 is conscious and slow.

System 1 can do multiple passes and all that, the speed is related to how aware are you of the computation occuring and system 2 must be consciously managed.

Example: You write a quick reply to a comment - thats system 1

You add two four digit numbers in your head - that will be system 2 unless you are very good, then it can be system 1 also

Why? Because memory allocations and addition computations are manually managed.