In Thinking, Fast and Slow, Daniel Kahneman famously posits that human thought operates through two systems: fast, intuitive System 1 and slow, deliberate System 2.

System 1 operates automatically and quickly, with little or no effort and no sense of voluntary control. (20)

System 2 allocates attention to the effortful mental activities that demand it, including complex computations. (21)

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. (21)

The capabilities of System 1 include innate skills that we share with other animals. (21)

System 1 has learned associations between ideas; it has also learned skills. (22)

System 2 is activated when an event is detected that violates the model of the world that System 1 maintains. (24)

A general “law of least effort” applies to cognitive as well as physical exertion. (35)

When you are actively involved in difficult cognitive reasoning or engaged in a task that requires self-control, your blood glucose level drops. (43)

Intelligence is not only the ability to reason; it is also the ability to find relevant material in memory and to deploy attention where needed. (46)

David Hume reduced the principles of association to three: resemblance, contiguity in time and place, and causality. (52)

There are different types of links: causes are linked to their effects (virus → cold); things to their properties (lime → green); things to the categories to which they belong (banana → fruit). (52)

Your actions and your emotions can be primed by events of which you are not even aware. (53)

Reciprocal links are common in the associative network (e.g., happy ↔ smile). (54)

When you are in a state of cognitive ease, you are probably in a good mood, like what you see, believe what you hear, trust your intuitions, and feel that the current situation is comfortably familiar. (60)

When you feel strained, you are more likely to be vigilant and suspicious, invest more effort in what you are doing, feel less comfortable, and make fewer errors, but you are also less intuitive and less creative than usual. (60)

A reliable way to make people believe in falsehoods is frequent repetition, because familiarity is not easily distinguished from truth. (62)

The aphorisms were judged more insightful when they rhymed. (63)

Creativity is associative memory that works exceptionally well. (67)

The main function of System 1 is to maintain and update a model of your personal world, which represents what is normal in it. The model is constructed by associations that link ideas of circumstances, events, actions, and outcomes that co-occur with some regularity. (71)

Violations of normality are detected with astonishing speed and subtlety. (74)

We have norms for a vast number of categories, and these norms provide the background for the immediate detection of anomalies such as pregnant men and tattooed aristocrats. (74)

System 1, which understands language, has access to norms of categories, which specify the range of plausible values as well as the most typical cases. (74)

We see causality, just as directly as we see color. (76)

When System 2 is otherwise engaged, we will believe almost anything. System 1 is gullible and biased to believe, System 2 is in charge of doubting and unbelieving, but System 2 is sometimes busy and often lazy. (81)

People seek data that are likely to be compatible with the beliefs they currently hold. (81)

Sequence matters because the halo effect increases the weight of first impressions. (83)

System 1 is radically insensitive to both the quality and the quantity of the information that gives rise to impressions and intuitions. (86)

It is the consistency of the information that matters for a good story, not its completeness. (87)

System 1 represents categories by a prototype or a set of typical exemplars. (93)

People let their likes and dislikes determine their beliefs (affect heuristic). (103)

System 1 is a machine for jumping to conclusions. (114)

You will more often than not err by misclassifying a random event as systematic. (117)

You will be influenced by the asking price (anchor effect). (120)

Awareness of your own biases can contribute to peace in marriages. (131)

Both spouses remember their own individual efforts and contributions much more clearly than those of the other (availability bias). (131)

People make judgments and decisions by consulting their emotions (affect heuristic). (139)

Stereotypes, both correct and false, are how we think of categories. (169)

Compelling causal statistics will not change long-held beliefs. (174)

Surprising individual cases (stories) have a powerful impact. (174)

Rewards for improved performance work better than punishment of mistakes. (174)

Once you adopt a new view of the world (or of any part of it), you immediately lose much of your ability to recall what you used to believe before your mind changed. (202)

Confidence is a feeling, which reflects the coherence of the information and the cognitive ease of processing it. (212)

Facts that threaten people’s livelihood and self-esteem are simply not absorbed. (216)

We know that people can maintain an unshakable faith in any proposition, however absurd, when they are sustained by a community of like-minded believers. (217)

People who spend their time and earn their living studying a particular topic produce poorer predictions than dart-throwing monkeys. (219)

The aversion to algorithms making decisions that affect humans is rooted in the strong preference that many people have for the natural over the synthetic or artificial. (228)

Most of us view the world as more benign that it really is. (255)

Optimists are normally cheerful and happy, and therefore popular. (255)

The evidence suggests that optimism is widespread, stubborn, and costly. (257)

90% of drivers believe they are better than average. (259)

CFOs were grossly overconfident about their ability to forecast the market. (262)

Optimism is highly valued socially and in the market; people and firms reward the providers of dangerously misleading information more than they reward truth tellers. (262)

Animals, including people, fight harder to prevent losses than to achieve gains. (305)

Loss aversion is a powerful conservative force that favors minimal changes from the status quo. (305)

Strangers who observe unfair behavior often join in the punishment. (308)

It is the departure from the default that produces regret. (348)

Judgments and preferences are coherent within categories but potentially incoherent when the objects that are evaluated belong to different categories. (357)

90% survival sounds encouraging whereas 10% mortality is frightening. (367)

Most of us passively accept decision problems as they are framed and therefore rarely have an opportunity to discover the extent to which our preferences are frame-bound rather than reality-bound. (367)

Happiness is the experience of spending time with people you love and who love you. (395)

A disposition for well-being is as heritable as height or intelligence. (401)

Nothing in life is as important as you think it is when you are thinking about it. (402)

Book Notes

All maps are traps. In this book, the trap is the false dichotomy of System 1 and 2, which reinforces our associated binary biases (e.g., think-feel, reason-emotion, rational-irrational). To be fair, Daniel Kahneman does explain that it’s just a metaphor.

Systems 1 and 2 are not systems in the standard sense of entities with interacting aspects or parts. And there is no part of the brain that either of the systems would call home. (29)

But he of all people knows the power of categories and labels to influence behavior and belief. In my experience, fast-slow and think-feel are deeply intertwingled, and so I do not identify my mind’s I or my self with one “system” or another (as does Kahneman).

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. (21)

In Song of Myself, Walt Whitman says “I am large, I contain multitudes.” I agree. And I identify with my unconscious and intuitive and feeling selves as much as any other.

As I work on Natural Information Architecture, I’m sharing notes and quotes from my sources of inspiration and provocation. As always, your questions and suggestions are welcome.