The Israeli bus suicide bombings were a series of terrorist attacks that became a defining example of the possibility effect: people responded not to the small probability of harm but to the vivid possibility of catastrophic harm. Between December 2001 and September 2004, 23 bombings killed 236 people in Israel, a grim toll that remained statistically tiny beside the approximately 1.3 million daily bus riders. Yet the attacks reshaped ordinary movement, attention, and emotional life, showing how terrorism can make a rare event feel perpetually near.

Causes and Background

During the period of the bombings, buses were a specific and highly accessible setting for danger. Travelers avoided them whenever possible, while those who continued to ride spent their journeys scanning fellow passengers for packages or bulky clothing that might conceal a bomb. The danger was not merely an abstract national threat: the sight of a bus supplied an immediate cue that connected an ordinary commute with images of death and destruction.

The attacks therefore worked through more than the number of victims or the calculated probability of another bombing. Repeated media coverage and frequent conversations continually reinforced the image, making it easier to recall and harder to suppress. The event’s psychological force came from the conjunction of rarity, vividness, and catastrophic consequence. A small chance of an ordinary mishap could remain emotionally weak, while a small chance of a bombing could become dominant because the imagined outcome was so terrible and the mental image so available.

What Happens

Daniel Kahneman’s own experience makes the mechanism concrete. He usually traveled by rented car rather than bus, but he found that he disliked stopping beside a bus at a red light and drove away faster than usual when the light changed. He recognized that he was more likely to be injured in a driving accident than by stopping next to a bus, and he knew that his behavior assigned an excessively high decision weight to a minuscule probability. His avoidance was not a reasoned attempt to maximize survival; being next to a bus made him think of bombs, and escaping the bus brought immediate relief from those unpleasant thoughts.

This reaction demonstrates the division between System 1 and System 2. System 2 could recognize that the risk was negligible, but that recognition did not dissolve the discomfort generated automatically by System 1. The emotional response was associative, involuntary, and relatively insensitive to the exact probability. If residents of one city were told that two bombers were ready to strike while residents of another were told that only one bomber was present, the second city would face half the stated risk, but the difference might not produce a proportionate sense of safety.

The bombings thus generated an availability cascade. A vivid image of violence became more mentally accessible as it was repeated through news and social discussion; that accessibility intensified fear; fear encouraged protective action; and the protective action confirmed the event’s importance in public attention. The attacks could therefore influence behavior even when no bombing was occurring. The threat lived on as a recurring association attached to buses, roads, and neighboring passengers.

Consequences and Aftermath

The immediate consequence was behavioral avoidance. People altered their transportation choices, watched strangers with suspicion, and experienced routine bus travel as an exercise in threat detection. Kahneman’s conduct beside buses shows that the effect extended beyond direct victims and regular passengers: the attacks changed the behavior of observers who understood the statistics and had no immediate evidence that a particular bus was dangerous.

The bombings also clarify why terrorism is effective as a form of psychological violence. Its impact is not measured only by the number of people physically harmed. A rare attack can impose a much larger emotional and behavioral cost by converting ordinary public spaces into reminders of possible catastrophe. The discrepancy between the 236 recorded fatalities and the enormous population exposed to the image of the attacks is precisely what makes the example analytically important: the public response exceeded what a neutral calculation of individual risk would predict.

The same structure appears in other reactions to rare possibilities. A feared gas explosion may lead people to demand mitigation despite knowing that the risk is minuscule, while a large lottery prize encourages purchases through pleasant fantasies despite an equally negligible chance of winning. In both cases, possibility matters more than probability. Terrorism produces avoidance and relief; the lottery produces hope and excitement, but both responses show how emotion can overweight a remote outcome.

Psychological and Policy Significance

The Israeli bus suicide bombings helped refine the interpretation of prospect theory’s claim that highly unlikely events may be either ignored or overweighted. The attacks show why the same small probability can be neglected in one setting and exaggerated in another: vividness and emotional arousal determine whether the possibility becomes mentally available. The numerical probability alone cannot explain the response.

The example also separates knowledge from control. People may know that a threat is unlikely while remaining unable to prevent the associated thought or feeling from influencing action. System 1 cannot simply be switched off by supplying System 2 with better arithmetic. Rational information can coexist with avoidance, vigilance, and the desire to escape an unpleasant mental image.

For that reason, the bombings function in the book not only as historical violence but also as a case study in judgment under uncertainty. They reveal how public fear is amplified through repetition and salience, how emotional experience can overpower statistical reasoning, and how a rare event can occupy a disproportionate place in collective life. The lasting lesson is not that the fear was irrational in the sense of being unreal; it was that the felt significance of the threat was governed by its vivid possibility rather than by its tiny probability.