James Guszcza, Bryan Richardson, Daniel Kahneman

In Thinking, Fast and Slow, the Nobel Prize-winning founder of behavioral economics Daniel Kahneman … writes of two fictitious mental processes that he calls System 1 (“thinking fast”) and System 2 (“thinking slow”). System 1 mental operations are rapid and automatic; they are biased toward belief and confirmation rather than analysis and skepticism; they tend to jump to conclusions and infer causal relations based on thin, “cognitively available” evidence. They tend to neglect the importance of evidence that is neither emotionally vivid nor in plain sight. In contrast, System 2 mental operations are slow, deliberate, and seek logical coherence rather than “narrative” or “associative” coherence.

The bulk of our mental operations are System 1 in nature. And the rub is that System 1 thinking turns out to be terrible at statistics. Without time, effort, and either tools or special training, the human mind will reliably make novice statistical errors. Surprisingly, this often applies to trained mathematicians and laypeople alike.

So far are we from being natural statistical thinkers that Kahneman calls the human mind “a machine for jumping to conclusions.”