QNAS QNAS QnAs with Daniel Kahneman

Prashant Nair Science Writer

The science of human decision-making has monitored. This, for example, is how people long been a stronghold of psychologists. almost always manage to refrain from swear- Among the voices that abound in the litera- ing in polite company. However, the self- ture on how people make choices, one monitoring is fairly lax, and most of the time scholarly voice has remained strident through the suggestions that arise automatically from several decades. By studying human behavior system 1 are simply endorsed by system 2 and through the lens of economics, Princeton expressed in behavior. As a result, impressions University psychologist Daniel Kahneman turn into beliefs, and impulses into choices. has shown how inherent biases might in- However, if you wanted to monitor yourself Daniel Kahneman. fluence our choices, overtly and subliminally. closely all of the time, it would quickly become For his influential work on prospect theory, impossible because system 2 is much slower which holds that people make decisions based and less efficient than system 1. So the idea of Neglect of duration would make sense from on their perceptions of losses and gains rather replacing system 1 with system 2 is infeasible. an evolutionary perspective: after a threaten- than on final outcomes, Kahneman shared the PNAS: You write that system 2, the part of ing episode, it is important for an organism 2002 Nobel Memorial Prize in economics. the mind that helps us make considered deci- to remember how bad the threat was and Working together with late psychologist sions, tends to be less active in monitoring how the episode ended; how long the episode Amos Tversky, a longtime research partner, system 1 when a person is happy. What are lasted is essentially irrelevant. Kahneman demonstrated that decisions be- the implications of that finding? PNAS: The book also touches upon the im- lieved to be the result of deliberation often Kahneman: The finding that mood has sub- portance of familiarity to the acceptance of stem from educated guesses, rules-of-thumb, tle but pervasive effects on people’s thoughts a message or conclusion. To wit, you describe and pattern-recognition. In his book Thinking has emerged in the last 15 years or so. Gener- the mere-exposure effect. Can you explain the Fast and Slow, a critical success published ally, people become less vigilant when they are effect and its implications for communicating in 2011 and targeting a broad audience, in a good mood, when system 1 impulses are scientific messages to a lay audience? Kahneman: Kahneman reports on a wealth of experi- morelikelytoexpressthemselvesasbeliefsor The mere-exposure effect holds mental research that point to two modes of choices. It turns out that there is a close asso- that when we are repeatedly exposed to some- decision-making in the human mind: Whereas ciation between vigilance and the degree to thing, we tend to trust or like it more. The fi system 1 is automatic, effortless, and rapid, which system 2 supervises system 1. What’s evolutionary justi cation for the effect, as more, the relationship is reciprocal: when the proposed by the late Robert Zajonc, is that rushing to judgment based on heuristics, ’ fluency of associative processing is low, it tends if you ve been in prolonged contact with some- system 2 is deliberate, effortful, and slow, ’ plodding through reason before reaching to result in bad mood, which, in turn, affects thing and it hasn tkilledyou,thenitmust conclusions. Understanding how we toggle associative processing. So people are more be relatively safe. The increasing sense of between the two systems, Kahneman says, can likely to make more superficial mistakes when safety with the familiar is thus an important help us make sense of a broad swath of human they are in a good mood; it’s not an enormous aspect of our everyday lives. However, sci- entificmessagesdon’t always lend themselves behavior. On the occasion of the 2012 Sackler effect but a fairly consistent one. ’ colloquium The Science of Science Communi- PNAS: You also distinguish between two to easy repetition, so I m not convinced of the value of repeating slogans to get scien- cation, where he was the keynote speaker, kinds of well-being: experienced and remem- fi Kahneman discussed his work with PNAS. bered. You note that memories of an experi- ti c ideas across to a wide audience. PNAS:Whatmotivatedyoutowriteapop- ence are influenced by its intensity and ending, On the other hand, science communicators ular book for a general audience? not by its duration. And to support the asser- should realize that if the message is intended to Kahneman: ’ ’ lead to action, they are effectively addressing I ve had a long career and tion, you cite experiments with people srecol- ’ worked in many fields. This book, which lection of unpleasantness during colonoscopies people s system 1, which thrives on stories, in- dividual anecdotes rather than statistics or ev- is not an autobiographical account, is a review administered under different conditions. ’ of many of those fields. I wanted to write a book Can you elaborate on your findings? idence. And most people s beliefs are shaped that would speak not only to the public but also Kahneman: Associative memory, or system not by arguments but by the beliefs of others to future scholars. Articles may become dated 1, works by producing chunks of narrative. they trust. Counterintuitive as it may seem to or less easily accessible, but a scholarly book that Certain aspects of the narrative, such as causal scientists, most people believe in conclusions before they accept arguments. So stories and appeals to a wide audience might endure. relations, tend to be emphasized. However, the source credibility are at least as important as PNAS: In the book you describe two duration of an experience is generally not the quality of arguments when it comes to the fictitious systems in our mind—systems 1 very important in assessing its overall value. public acceptance of scientificideas. and 2—that underlie our automatic and con- This is similar to narratives where events are sidered decisions, respectively. Would an critical and the uneventful passage of time is acuteawarenessoftheexistenceofthese ignored. We are aware of how long experi- This QnAs arises from the 12th Annual Sackler Lecture held May two systems allow people to suppress system ences last, and we certainly know that it’s 21, 2012 at the National Academy of Sciences in Washington, DC in conjunction with the Sackler Colloquium on The Science 1 while making decisions? better for good experiences to last longer Kahneman: of Science Communication. The Colloquium papers begin on Mostofthetimewefollow and bad experiences to be brief. However, page 14031 of the Supplement to this Issue. The video of the system 1; our impulses are generated au- our spontaneous evaluation of past experi- lecture can be viewed at https://www.youtube.com/watch?v= tomatically, but they are also continuously ences is generally quite insensitive to duration. di6kl4ViWgk&list=TLgKpPUi_8_x8.

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