European Journal of Operational Research 177 (2007) 1333–1352 www.elsevier.com/locate/ejor The affect heuristic q Paul Slovic *, Melissa L. Finucane, Ellen Peters, Donald G. MacGregor Decision Research Inc., 1201 Oak Street, Suite 200, Eugene, OR 97401, USA Available online 16 October 2006 Abstract This paper introduces a theoretical framework that describes the importance of affect in guiding judgments and deci- sions. As used here, ‘‘affect’’ means the specific quality of ‘‘goodness’’ or ‘‘badness’’ (i) experienced as a feeling state (with or without consciousness) and (ii) demarcating a positive or negative quality of a stimulus. Affective responses occur rapidly and automatically—note how quickly you sense the feelings associated with the stimulus word ‘‘treasure’’ or the word ‘‘hate’’. We argue that reliance on such feelings can be characterized as ‘‘the affect heuristic’’. In this paper we trace the development of the affect heuristic across a variety of research paths followed by ourselves and many oth- ers. We also discuss some of the important practical implications resulting from ways that this heuristic impacts our daily lives. Ó 2002 Cambridge University Press. Published by Elsevier B.V. Keywords: Affect heuristic; Judgment; Decision making; Risk perception 1. Background nized as an important component of human judg- ment and decision making. Perhaps befitting its Although affect has long played a key role in rationalistic origins, the main focus of descriptive many behavioral theories, it has rarely been recog- decision research has been cognitive, rather than affective. When principles of utility maximization appeared to be descriptively inadequate, Simon q Reprinted from Gilovich, T., Griffin, D., Kahneman, D. (1956) oriented the field toward problem solving (Eds.), 2002. Heuristics and Biases: The Psychology of Intuitive and information-processing models based upon Judgment. Cambridge University Press, New York. pp. 397– 420. Ó Cambridge University Press 2002. Reprinted with per- bounded rationality. The work of Tversky and mission. Financial support for the writing of this paper was Kahneman (1974) and Kahneman et al. (1982) provided by the National Science Foundation under Grant SES demonstrated how boundedly rational individuals 9876587. * employ heuristics such as availability, representa- Corresponding author. Tel.: +1 541 485 2400; fax: +1 541 tiveness, and anchoring and adjustment to make 485 2403. E-mail address: [email protected] (P. Slovic). judgments and how they use simplified strategies URL: http://www.decisionresearch.org (P. Slovic). such as ‘‘elimination by aspects’’ to make choices 0377-2217/$ - see front matter Ó 2002 Cambridge University Press. Published by Elsevier B.V. doi:10.1016/j.ejor.2005.04.006 1334 P. Slovic et al. / European Journal of Operational Research 177 (2007) 1333–1352 (Tversky, 1972). Other investigators elaborated the matic, natural, nonverbal, narrative, and cognitive strategies underlying judgment and experiential, and the other analytical, deliberative, choice through models of constructed preferences verbal, and rational. (p. 710) (Slovic, 1995; Payne et al., 1993), dominance struc- One of the characteristics of the experiential turing (Montgomery, 1983), and comparative system is its affective basis. Although analysis is advantages (Shafir et al., 1989). In 1993, the entire certainly important in some decision-making cir- volume of the journal Cognition was dedicated to cumstances, reliance on affect and emotion is a the topic, Reason-Based Choice, in which it was quicker, easier, and more efficient way to navigate argued that ‘‘Decisions ... are often reached by in a complex, uncertain, and sometimes dangerous focusing on reasons that justify the selection of world. Many theorists have given affect a direct one option over another’’ (Shafir et al., 1993, p. and primary role in motivating behavior. Epstein’s 34). Similarly, a state-of-the-art review by Buse- (1994) view on this is as follows: meyer et al. (1995) was titled ‘‘Decision Making from a Cognitive Perspective’’. In keeping with The experiential system is assumed to be intimately its title, it contained almost no references to the associated with the experience of affect, ... which influence of affect on decisions. refer[s] to subtle feelings of which people are often Despite this cognitive emphasis, the importance unaware. When a person responds to an emotion- of affect is being recognized increasingly by deci- ally significant event ... the experiential system sion researchers. A limited role for affect was automatically searches its memory banks for acknowledged by Shafir et al. (1993) who conceded related events, including their emotional accompa- that ‘‘People’s choices may occasionally stem from niments ... If the activated feelings are pleasant, affective judgments that preclude a thorough eval- they motivate actions and thoughts anticipated to uation of the options’’ (p. 32, emphasis added). reproduce the feelings. If the feelings are unpleas- A strong early proponent of the importance of ant, they motivate actions and thoughts antici- affect in decision making was Zajonc (1980), who pated to avoid the feelings. (p. 716) argued that affective reactions to stimuli are often Also emphasizing the motivational role of the very first reactions, occurring automatically affect, Mowrer (1960a,b) conceptualized condi- and subsequently guiding information processing tioned emotional responses to images as prospec- and judgment. According to Zajonc, all percep- tive gains and losses that directly ‘‘guide and tions contain some affect. ‘‘We do not just see ‘a control performance in a generally sensible adap- house’: We see a handsome house, an ugly house, tive manner’’ (1960a, p. 30). He criticized theorists or a pretentious house’’ (p. 154). He later adds, who postulate purely cognitive variables such as ‘‘We sometimes delude ourselves that we proceed expectancies (probabilities) intervening between in a rational manner and weight all the pros and stimulus and response, cautioning that we must cons of the various alternatives. But this is proba- be careful not to leave the organism at the choice bly seldom the actual case. Quite often ‘‘I decided point ‘‘lost in thought’’. Mowrer’s solution was in favor of X’’ is no more than ‘‘I liked X ...’’ We to view expectancies more dynamically (as condi- buy the cars we ‘‘like’’, choose the jobs and houses tioned emotions such as hopes and fears) serving we find ‘‘attractive’’, and then justify these choices as motivating states leading to action. by various reasons...’’ (p. 155). One of the most comprehensive and dramatic Affect also plays a central role in what have theoretical accounts of the role of affect in decision come to be known as ‘‘dual-process theories’’ of making is presented by the neurologist, Antonio thinking, knowing, and information processing. Damasio (1994), in his book Descartes’ Error: As Epstein (1994), has observed, Emotion, Reason, and the Human Brain. Damasio’s There is no dearth of evidence in every day life that theory is derived from observations of patients people apprehend reality in two fundamentally dif- with damage to the ventromedial frontal cortices ferent ways, one variously labeled intuitive, auto- of the brain that has left their basic intelligence, P. Slovic et al. / European Journal of Operational Research 177 (2007) 1333–1352 1335 memory, and capacity for logical thought intact cludes that somatic markers increase the accuracy but has impaired their ability to ‘‘feel’’—that is, and efficiency of the decision process and their to associate affective feelings and emotions with absence degrades decision performance. the anticipated consequences of their actions. Damasio tested the somatic marker hypothesis Close observation of these patients combined with in a decision making experiment in which subjects a number of experimental studies led Damasio to gambled by selecting cards from any of four decks. argue that this type of brain damage induces a Turning each card resulted in the gain or loss of a form of sociopathy (Damasio et al., 1990) that sum of money, as revealed on the back of the card destroys the individual’s ability to make rational when it was turned. Whereas normal subjects and decisions; that is, decisions that are in his or her patients with brain lesions outside the prefrontal best interests. Persons suffering this damage sectors learned to avoid decks with attractive large became socially dysfunctional even though they payoffs but occasional catastrophic losses, patients remain intellectually capable of analytical with frontal lobe damage did not, thus losing a reasoning. great deal of money. Although these patients Commenting on one particularly significant responded normally to gains and losses when they case, Damasio observes: occurred (as indicated by skin conductance responses immediately after an outcome was expe- The instruments usually considered necessary and rienced) they did not seem to learn to anticipate sufficient for rational behavior were intact in future outcomes (e.g., they did not produce nor- him. He had the requisite knowledge, attention, mal skin conductance responses when contemplat- and memory; his language was flawless; he could ing a future choice from a dangerous deck). In perform calculations; he could tackle the logic of other words, they failed to show any proper antic- an abstract problem. There was only one signifi- ipatory responses, even after numerous opportuni- cant accompaniment to his decision-making fail- ties