Israeli Defense Forces

The Israeli Defense Forces is presented not merely as a military institution but as a recurring testing ground for the psychology of judgment. Within its interview rooms, obstacle fields, training units, and wartime command structure, Daniel Kahneman encounters problems that later become central to his account of intuition: people mistake random variation for causal evidence, substitute an evaluation of present information for a prediction of the future, and place excessive faith in coherent impressions. The organization also supplies one of the book’s clearest demonstrations that intuition is not simply useless: when preceded by systematic observation and separate scoring, it can contribute to a prediction that is more reliable than an undisciplined global impression.

Military Setting and Institutional Role

The Israeli Defense Forces enters the narrative through Daniel Kahneman’s national service and remains important because its personnel decisions had immediate practical consequences. Kahneman, already trained in psychology but still very young, was assigned responsibilities that would ordinarily have seemed beyond his experience. In 1955, when he was a twenty-one-year-old lieutenant, he was asked to establish an interview system for the entire army. The historical circumstances mattered: Israel was only seven years old, its institutions were still being built, and Kahneman’s bachelor’s degree in psychology apparently made him the army’s best-trained psychologist, even though his direct supervisor held a degree in chemistry.

The organization’s selection apparatus combined psychometric testing, personality interviews, and later evaluations of performance. Every drafted soldier completed a battery of psychometric tests, while recruits being considered for combat duty were interviewed and assigned a general fitness score, along with a proposed match to branches such as infantry, artillery, or armor. The interviewers were young conscripts, mostly women exempt from combat duty at the time, who received only a few weeks of training before conducting fifteen- to twenty-minute interviews. Their task was to form an overall impression of how well each recruit would perform in military life, but follow-up evaluations showed that this procedure was almost useless as a predictor of future success.

Structured Selection and the Discovery of Disciplined Intuition

Kahneman redesigned the interview system after reading Paul Meehl’s argument that simple statistical rules could outperform intuitive clinical judgment. Instead of allowing interviewers to pursue whatever seemed psychologically interesting during a conversation, he required them to gather specific facts about the recruit’s ordinary life. Six characteristics were selected as relevant to performance in a combat unit, including responsibility, sociability, and masculine pride. Each characteristic was assessed through factual questions about matters such as the number of jobs the recruit had held, regularity and punctuality at work or school, frequency of contact with friends, and participation in sports.

The procedure was deliberately sequential. Interviewers rated each trait separately on a five-point scale and completed the six ratings in a fixed order, a design intended to limit the halo effect, in which an early favorable or unfavorable impression spreads across later judgments. They were told not to decide whether the recruit would succeed in the army. Their role was to obtain reliable measurements; a standard formula would combine the separate scores into a final fitness assessment.

The interviewers resisted the reform. They disliked being instructed to suppress their intuition and concentrate on factual questions, and one complained that the new method was turning them into robots. Kahneman compromised by allowing a final intuitive assessment: after completing the standardized interview, an interviewer could close her eyes, imagine the recruit as a soldier, and assign a score from one to five. The concession became an important part of the experiment rather than a retreat from it.

Several hundred interviews were followed by evaluations from the commanding officers of the units to which the soldiers were assigned. The sum of the six trait ratings predicted performance much more accurately than the old global evaluation, moving the system from “completely useless” to “moderately useful.” The surprising result was that the closing-eyes judgment performed just as well as the combined trait score. Kahneman therefore gave the intuitive assessment a weight equal to the sum of the six specific ratings. The lesson was not to trust intuition automatically, nor to dismiss it wholesale: intuition could add value after objective information had been collected and separate dimensions had been scored with discipline.

Decades later, after Kahneman had become a Nobel Prize winner and briefly a minor celebrity in Israel, he returned to his old army base. The unit still used a system that had changed little from the one he designed, and its commanding officer reported that research continued to show that the interviews worked well. At the end of her explanation, she repeated the final instruction: the interviewers still told candidates to close their eyes. The small ritual became a living reminder that structured procedure and intuitive synthesis need not be enemies when each is assigned a proper place.

Randomness, Regression, and Wartime Judgment

The Israeli Defense Forces also illustrates the danger of explaining random outcomes through imagined causes. During the Yom Kippur War in 1973, the Israeli Air Force suffered heavily because Egyptian ground-to-air missiles performed unexpectedly well. Kahneman was told that two squadrons operating from the same base had experienced sharply different losses: one had lost four planes, while the other had lost none. An investigation began on the assumption that the unfortunate squadron might be doing something wrong.

The evidence did not support that assumption. There was no prior reason to believe that one squadron was more effective than the other, and investigators found no operational difference between them. The pilots’ lives nevertheless varied in many incidental ways, including how often they went home between missions and details of how debriefings were conducted. Kahneman advised senior officers in the Israeli Air Force to stop the investigation. In his judgment, blind luck was the most likely explanation, and a search for a hidden cause in a small, uneven sample was unlikely to succeed. Continuing the interviews would also impose an additional burden on pilots who had suffered losses by implying that they, or their dead colleagues, were responsible for outcomes that might simply have been random.

This episode connects the organization’s wartime experience to the broader problem of seeing patterns in chance. Uneven outcomes feel as though they demand an explanation, particularly when lives are at stake, but small samples naturally produce conspicuous differences. The military setting makes the moral cost of misreading randomness especially clear: an erroneous causal story can become an accusation against people already carrying the consequences of failure.

A related lesson appears in the army’s officer-training selection process. While serving with a unit that selected candidates through interviews and field tests, Kahneman later asked officers to predict the final grades that future cadets would receive at officer school. The officers knew the grading system and the approximate proportions of A’s, B’s, and other grades. Their forecasts reproduced those proportions almost exactly, indicating that they were not merely evaluating each candidate’s current evidence; they were also, at least implicitly, matching their predictions to the known distribution of outcomes. The example exposed the difference between predicting a future result and judging the evidence presently available, a distinction people often fail to maintain.

The Leaderless Group Challenge and the Illusion of Validity

During his national service, Kahneman also helped evaluate officer candidates through a “leaderless group challenge,” a test developed from methods used by the British Army in World War II. Eight strangers, stripped of rank insignia and identified only by numbered tags, had to lift a long log from the ground and carry it to a wall about six feet high. Every member had to reach the other side without the log touching the ground or wall and without anyone touching the wall. Any violation required the group to begin again.

The task offered several possible solutions. Some candidates crossed by crawling over the log while others held it at an angle; some climbed onto one another’s shoulders and jumped. The final candidate faced the most difficult maneuver, having to reach the suspended pole, move along it while the group kept both person and log in the air, and leap safely over the wall. Failure at this stage was common, forcing the whole group to repeat the exercise.

The test gave observers a vivid stream of behavior from which to form impressions of leadership, cooperation, and military potential. Yet its narrative role is cautionary. Kahneman presents the army’s evaluative environment as one in which observers can become confident because a candidate’s behavior creates a coherent story, even when the evidence is limited and the relationship between performance on the obstacle field and later success is weak. The organization thus demonstrates the illusion of validity: confidence can arise from the internal consistency of an impression rather than from the actual predictive power of the method.

From Military Practice to General Decision Systems

The institutional lessons developed inside the Israeli Defense Forces extend into the book’s wider arguments about forecasting and organizational choice. Kahneman’s early redesign of recruitment interviews anticipates the principle that judgments should be decomposed into observable components, gathered independently, and combined by a rule rather than left to an improvised overall impression. His wartime advice anticipates the warning that random variation should not be converted into a story about hidden performance differences. His later work on prediction shows why military or governmental organizations should distinguish evaluation from forecasting and compare expert judgment with simple statistical baselines.

The same concerns appear in Kahneman’s discussion of the outside view and the planning fallacy. A curriculum team assembled with the support of the Israeli Ministry of Education confidently estimated how long it would take to complete a textbook, even though comparable projects supplied a more sobering reference class. The organization of knowledge itself could not guarantee good prediction: people who possess relevant information may still favor the inside view, focusing on the particular project and its apparent plan while neglecting distributional evidence about similar undertakings.

The Israeli Defense Forces therefore serves as a bridge between laboratory psychology and institutional design. Its selection system shows how standardized factual questions, fixed scoring, and a controlled role for intuition can improve decisions. Its combat experience shows how randomness can be mistaken for evidence of skill or failure. Its officer-training and group-testing practices reveal how confidence grows from coherent impressions. Taken together, these episodes make the organization one of the book’s most concrete demonstrations that better judgment depends less on eliminating human intuition than on building procedures that expose, constrain, and appropriately use it.