Matt’s Reviews > Thinking, Fast and Slow > Status Update

System 1 does basic assessments quickly. It can to averages well, but not sums. Sums needs system 2. This is because system 1 represents categories by prototypes or sets of typical exemplars. System 1 can intensity match, e.g., if Julia learned to read at 2 years what is her college GPA. System 1 does more than you ask, like a shotgun. Ask to compare rhymes and you will also see the spelling.