Thinking, Fast and Slow - System One and Two - Daniel Kahneman (2012)

Two Systems

The distinction between fast and slow thinking has been explored by many psychologists over the last twenty-five years. For reasons that I explain more fully in the next chapter, I describe mental life by the metaphor of two agents, called System 1 and System 2, which respectively produce fast and slow thinking.

It emerges from recent research, the intuitive System 1 is more influential than your experience tells you, and it is the secret author of many of the choices and judgments you make.

System 1 operates automatically and quickly, with little or no effort and no sense of voluntary control. 

System 2 allocates attention to the effortful mental activities that demand it, including complex computations. 

The operations of System 2 are often associated with the subjective experience of agency, choice, and concentration. 

The labels of System 1 and System 2 are widely used in psychology, but I go further than most in this book, which you can read as a psychodrama with two characters. When we think of ourselves, we identify with System 2, the conscious, reasoning self that has beliefs, makes choices, and decides what to think about and what to do. 

Although System 2 believes itself to be where the action is, the automatic System 1 is the hero of the book. I describe System 1 as effortlessly originating impressions and feelings that are the main sources of the explicit beliefs and deliberate choices of System 2.

 The highly diverse operations of System 2 have one feature in common: they require attention and are disrupted when attention is drawn away.

System 2 has some ability to change the way System 1 works, by programming the normally automatic functions of attention and memory.