Plot Synopsis

      The interaction of the two systems is a recurrent theme   of the book, and abrief synopsis of the plot is in order. In the story I will tell, Systems 1 and 2are both active whenever we are awake. System 1 runs automatically andSystem 2 is normally in a comfortable low-effort mode, in which only afraction of its capacity is engaged. System 1 continuously generatessuggestions for System 2: impressions, intuitions, intentions, and feelings.If endorsed by System 2, impressions and intuitions turn into beliefs, andimpulses turn into voluntary actions. When all goes smoothly, which is mostof the time, System 2 adopts the suggestions of System 1 with little or nomodification. You generally believe your impressions and act on yourdesires, and that is fine—usually.

      When System 1 runs into difficulty, it calls on System 2 to support moredetailed and specific processing that may solve the problem of themoment. System 2 is mobilized when a question arises for which System 1does not offer an answer, as probably happened to you when youencountered the multiplication problem 17 × 24. You can also feel a surgeof conscious attention whenever you are surprised. System 2 is activated when an event is detected that violates the model of the worldthat System 1 maintains. In that world, lamps do not jump, cats do not bark,and gorillas do not cross basketball courts. The gorilla experimentdemonstrates that some attention is needed for the surprising stimulus tobe detected. Surprise then activates and orients your attention: you willstare, and you will search your memory for a story that makes sense of thesurprising event. System 2 is also credited with the continuous monitoringof your own behavior—the control that keeps you polite when you areangry, and alert when you are driving at night. System 2 is mobilized toincreased effort when it detects an error about to be made. Remember atime when you almost blurted out an offensive remark and note how hardyou worked to restore control. In summary, most of what you (your System2) think and do originates in your System 1, but System 2 takes over whenthings get difficult, and it normally has the last word.

      The division of labor between System 1 and System 2 is highly efficient:it minimizes effort and optimizes performance. The arrangement workswell most of the time because System 1 is generally very good at what itdoes: its models of familiar situations are accurate, its short-termpredictions are usually accurate as well, and its initial reactions tochallenges are swift and generally appropriate. System 1 has biases,however, systematic errors that it is prone to make in specifiedcircumstances. As we shall see, it sometimes answers easier questions than the one it was asked, and it has little understanding of logic andstatistics. One further limitation of System 1 is that it cannot be turned off. Ifyou are shown a word on the screen in a language you know, you will readit—unless your attention is totally focused elsewhere.

笔记：系统1足以应付日常，但对于复杂事物需要系统二的辅助。