Risk Perception and Affect

Humans perceive and act on risk in two fundamental ways. Risk as feelings refers to individuals’ instinctive and intuitive reactions to danger. Risk as analysis brings logic, reason, and scientific deliberation to bear on risk management. Reliance on risk as feelings is described as ‘‘the affect heuristic.’’ This article traces the development of this heuristic and discusses some of the important ways that it impacts how people perceive and evaluate risk. KEYWORDS—risk perception; risk analysis; the affect heuristic Risk in the modern world is perceived and acted upon in two fundamental ways. Risk as feelings refers to our instinctive and intuitive reactions to danger. Risk as analysis brings logic, reason, and scientific deliberation to bear on risk assessment and decision making. This article discusses what recent research reveals about risk as feelings, an important vestige of humans’ evolutionary journey. That intuitive feelings are still the predominant method by which human beings evaluate risk is cleverly illustrated in a cartoon by Doonesbury creator, Garry Trudeau. Two characters decide whether it is safe to greet one another on a city street by systematically tabulating a list of risk and risk-mitigating factors to determine which are more numerous. The reader instantly recognizes that people in such a situation would never be this analytical, even if their lives were at stake. Most risk analysis in daily life is handled quickly and automatically by feelings arising from what is known as the ‘‘experiential’’ mode of thinking. BACKGROUND AND THEORY: THE IMPORTANCE OF SPECIFIC EMOTIONS AND AFFECT Strong visceral emotions such as fear and anger sometimes play a role in risk as feelings. These two emotions appear to have opposite effects—fear amplifies risk estimates, and anger attenuates them (Lerner, Gonzalez, Small, & Fischhoff, 2003; Lerner & Keltner, 2000). Lerner and colleagues have explained these differences by proposing that fear arises from appraisals of uncertainty and situational control, whereas anger arises from appraisals of certainty and individual control. Fortunately, most of the time people are in a calmer state, being guided by much subtler feelings. We shall focus this review on a ‘‘faint whisper of emotion’’ called affect. We use the term affect to mean the specific quality of ‘‘goodness’’ or ‘‘badness’’ (a) experienced as a feeling state (with or without consciousness) and (b) demarcating a positive or negative quality of a stimulus. We have used the term ‘‘the affect heuristic’’ to characterize reliance on such feelings (Slovic, Finucane, Peters, & MacGregor, 2002); the experienced feelings are used as information to guide judgment and decision making (Schwarz & Clore, 1988). Affect plays a central role in what are known as dual-process theories of thinking. According to these theories, people apprehend reality in two fundamentally different ways, one labeled intuitive, automatic, natural, nonverbal, narrative, and experiential, and the other analytical, deliberative, and verbal (see, e.g., Epstein, 1994). One of the main characteristics of the intuitive, experiential system is its affective basis. Although analysis is certainly important in some decision-making circumstances, reliance on affect is generally a quicker, easier, and more efficient way to navigate in a complex, uncertain, and sometimes dangerous world. Many theorists have given affect a direct and primary role in motivating behavior. Pleasant feelings motivate actions that people anticipate will reproduce those feelings. Unpleasant feelings motivate actions that people anticipate will avoid those feelings. There are strong elements of rationality in both systems of thinking. The experiential system enabled human beings to survive as they evolved. Intuition, instinct, and gut feeling were relied upon to determine whether an animal was safe to approach or the water was safe to drink. As life became more complex and humans gained more control over their environment, analytic tools such as probability theory, risk assessment, and decision analysis were invented to ‘‘boost’’ the rationality of experiential thinking. THE AFFECT HEURISTIC Evidence of risk as feelings was present in early studies of risk perception (Fischhoff, Slovic, Lichtenstein, Read, & Combs, 1978). Those studies showed that feelings of dread were the major deterAddress correspondence to Paul Slovic, Decision Research, 1201 Oak Street, Suite 200, Eugene, OR 97401; e-mail: pslovic@darkwing. uoregon.edu. CURRENT DIRECTIONS IN PSYCHOLOGICAL SCIENCE 322 Volume 15—Number 6 Copyright r 2006 Association for Psychological Science miner of public perception and acceptance of risk for a wide range of hazards. This explained, for example, why the public judges radiation exposure from nuclear power plants (highly dreaded) as far riskier than radiation from medical X-rays—an assessment not shared by risk experts. In today’s world, terrorism has replaced nuclear power at the top of the list of widely dreaded risks. Risk and Benefit Judgments Research has found that, whereas risk and benefit tend to be positively correlated across hazardous activities in the world (i.e., high-risk activities tend to have greater benefits than do low-risk activities), they are negatively correlated in people’s minds and judgments (i.e., high risk is associated with low benefit, and vice versa). The significance of this finding was not realized until a study by Alhakami and Slovic (1994) found that the inverse relationship between perceived risk and perceived benefit of an activity (e.g., using pesticides) was linked to the strength of positive or negative affect associated with that activity as measured by rating the activity on bipolar scales such as good/bad, nice/awful, and so forth. This finding implies that people judge a risk not only by what they think about it but also by how they feel about it. If their feelings toward an activity are favorable, they tend to judge the risks as low and the benefits as high; if their feelings toward the activity are unfavorable, they tend to make the opposite judgment—high risk and low benefit (i.e., the affect heuristic; Finucane, Alhakami, Slovic, & Johnson, 2000). If affect guides perceptions of risk and benefit, then providing information about benefit should change people’s perception of risk and vice versa (see Fig. 1). For example, information stating that benefit is high for a technology such as nuclear power should lead to more positive overall affect, which should, in turn, decrease perceived risk (Fig. 1A). Finucane et al. (2000) tested this hypothesis for various technologies, providing information designed to manipulate affect by increasing or decreasing perceived benefit for the technology or by increasing or decreasing its perceived risk. Their predictions were confirmed. Further support for the affect heuristic came from a second experiment by Finucane et al. showing that the inverse relationship between perceived risks and benefits increased greatly under time pressure, when opportunity for analytic deliberation was reduced. Coupled with the findings of Alhakami and Slovic (1994), these experiments indicate that affect influences judgment directly and is not simply a response to a prior analytic evaluation. As a key element of experiential thinking, the affect heuristic was essential to risk assessment and survival during the evolution of the human species. But, as we describe below, affect can also mislead people. Judgments of Probability, Relative Frequency, and Risk The experiential system of thinking encodes reality in images, metaphors, and narratives to which affective feelings have become attached. To demonstrate this, Denes-Raj and Epstein (1994) showed that, when offered a chance to win $1 by drawing a red jelly bean from an urn, individuals often elected to draw from a bowl containing a greater absolute number of red beans but a smaller proportion of them (e.g., 7 in 100) rather than from a bowl with fewer red beans but a better probability of winning (e.g., 1 in 10). These individuals reported that, although they knew the probabilities were against them, they felt they had a better chance when there were more red beans. We can characterize Denes-Raj and Epstein’s subjects as following a mental strategy of ‘‘imaging the numerator’’ (i.e., the number of red beans) and neglecting the denominator (the number of beans in the bowl). Consistent with the affect heuristic, images of winning beans convey positive affect that motivates choice. Although the jelly-bean experiment may seem frivolous, imaging the numerator brings affect to bear on judgments in ways that can be both nonintuitive and consequential. Slovic, Monahan, and MacGregor (2000) demonstrated this by asking experienced forensic psychologists and psychiatrists to judge the likelihood that a hospitalized mental patient, ‘‘Mr. Jones,’’ would commit an act of violence within 6 months after being discharged from the facility. An important finding was that clinicians who were given another expert’s assessment of the patient’s risk of violent behavior framed in terms of relative frequency subsequently labeled him as more dangerous than did clinicians who were shown a statistically ‘‘equivalent’’ risk expressed as a probability. For example, when clinicians were told that ‘‘20 out C A