Psychology & Communication

Sources of Power

How People Make Decisions

sources of power

Sentence summarizing “Sources of Power” : We all have to make decisions, and sometimes these decisions have important – or even dramatic – consequences, which must be taken into account at difficult times and within strong time constraints; how do firemen, soldiers and doctors take split-second decisions when lives are at stake? This book tells us about it, detailing various theories illustrated with stories and case studies.

By Gary Klein, 1998, 300 pages

Chronicle of “Sources of Power”:

In 1984, Gary Klein carried out his first case study to try and understand how people make decisions, particularly under heavy time constraints. The task was to study how firefighters make choices in the heat of the moment, as part of a contract struck with the US Army. Amongst the predictions suggested at the start of the study, the author and his team thought that the firefighters would only have little time on the field to think of all the options and that they would only consider two options: that which was intuitively their favorite and another, which would be used for comparison to demonstrate why the favored option was the best.

This hypothesis was based on the work of Peer Soelberg in 1967. He was a professor at MIT and taught his students how to make decisions using a rational choice strategy consisting of five stages:

  1. Identify the options
  2. Identify the means for evaluating these options
  3. Ponder on each dimension of the evaluation
  4. Calculate the score
  5. Take the decision with the highest score

For his hypothesis, Soelberh studied how his students made a natural and determining choice: choosing their first job whilst they were still finishing the course. He discovered that his students did not use the rational choice strategy, but instead followed their instinct and made the choice they felt the most attracted to. After interviewing his students, Soelberg was able to identify their favorite job and predict their final choice with a success rate of 87%, 3 weeks before his students would announce their decisions.

When Soelberg asked them if they had reached a decision, they would deny it, claiming that a choice is made by studying several possibilities, just as Soelberg had taught them. However Soelberg noticed that students, in order to feel like they had made a decision, tended to take another offer, compare it with their favorite choice, and then tried to demonstrate how much the latter was preferable. Then they would declare it to be their decision the instinctive choice Soelberg had previously identified. They were therefore not making a decision; they were constructing a justification.

Gary Klein and his team hence suggested that the firefighters would do likewise. But strangely, as they were interviewing Fire Officers, it appeared that they never seemed to simultaneously compare two options. Some Fire Officers even insisted on the fact that they never actually made decision, in the sense of studying two or several options at once in order to evaluate the strengths and weaknesses of each. They simply did not have the time. Everything would have burnt before they’d had the time to study all the options, never mind weighing and comparing. Let’s find out the decisional system firefighters actually use.

Chapter 3: The decision making model based on the first observation

Studying deeper, the researchers realized that Fire Officers did not refuse to compare options: they didn’t have to do it. Fire Officers are experienced firefighters. Even faced with a complex situation, they are able to see what is familiar to them and how to react. Their experience allows them to immediately identify the first thing to do to respond to a situation, therefore they do not bother thinking about other ones. They are not stubborn. They are competent. This is what the researchers call recognition-primed decision-making, or RPD model.

So does this mean that firefighters systematically implement the first thing that comes into their heads? No. They evaluate the feasibility and the chances of success of the first option that comes to mind. If these two parameters appear too weak, they then reject this first option and evaluate a second one, and so on, without comparing two possibilities at the same time. This is what the researchers call singular evaluation approach, to differentiate it from the comparative approach.

These are not easy to differentiate: when you are ordering a meal, you are probably going to compare all the dishes on offer to find the one you like the best. If you are in an unknown city and you are almost out of gas, you are going to look for gas stations and stop at the first decent one, without comparing all of the city’s gas stations in order to find the best value for money. Singular evaluation approach is therefore a strategy that makes you opt for a satisfactory decision. It is very different from making an optimized decision: in order to be satisfied, you only need to make the first decision you deem suitable, in order to optimize you need to consider a large number of choices and only select the best one. This satisfying decision strategy obviously makes sense in an emergency situation such as those firefighters encounter.

In his case, however, how can firefighters rule out or select an option, if they’re not comparing it to another? They use mental simulation: they mentally picture the scene from the option they are considering and can see the consequences happening in their heads. If these consequences appeal to them, they select the option. Otherwise, they mentally simulate the outcome of another decision.

As we will see below, mental simulation is not free of failures. But it is often the best available tool usable within the allocated time.

Before he began his study, the author thought that novices were jumping more impulsively on the first option they could think of, whereas the experts would carefully study the merits of each option. It in fact appeared that the opposite is true: experts know what to do and therefore immediately think of a viable solution faced with a problem, whereas novices have to compare various approaches, when they sometimes do not have time to do so.

Finally. Gary Klein and his team sorted the 156 decisions they collected during these studies into 4 categories:


Choosing from options they are given


Comparative Evaluation

18 (half come from a case where the firefighters had no experience)

Creative Decision (imagining solutions which had never been used before)


RPD, based on singular evaluation approach


Therefore, almost 80% of decisions were taken using singular evaluation approach based on the RPD model.


One of the first lessons to draw from this analysis is to be skeptical as to the formal decision methods. These are methods that are rarely used.

Chapter 4: The Power of Intuition

Intuition depends on the use of experience to recognize key patterns that indicate the dynamics of the situation. Because patterns can be subtle, people are often unable to describe what they have noticed and how they judged a situation as typical or atypical.

Therefore, intuition has a strange reputation. Skilled decision makers know that they can depend on their intuition, but at the same time, they may not trust a decision source that appears so accidental. The author was able to analyze this when one of the firefighters he was interviewing told him he had saved his own life and that of his men thanks to an Extra-Sensory Perception (ESP). Here is his story:

It was a straightforward house fire in a one-story house in a residential neighborhood. The fire was in the back, in the kitchen area. The lieutenant sent his hose crew into the house, to the back, in order to spray water on the fire, but the fire just roared back at once.

“Odd”, he thought. The water should have more of an impact. They tried spraying it again, with the same result. They retreated a little to regroup.

Then the lieutenant started to feel that something was wrong. He didn’t have any clues; he just didn’t like the idea of staying inside the house and ordered his men out of the building – a very average house, with nothing out of the ordinary.

As soon as the men left the building, the floor they had been standing on collapsed. Had they stayed inside, they would have been plunged into the flames below.

“A sixth sense”, he insisted, and a large part of the skills of each experienced commander. A few questions revealed the following facts:

  • He absolutely did not suspect that there was a basement underneath the house.
  • He did not suspect that the seat of the fire was located in the basement, underneath the living room where he and his men were standing before they left.
  • But he was wondering why the fire was not reacting as it should have done.
  • The living room was hotter than what he would have expected for a small kitchen fire in a small house.
  • Everything was very quiet. Fires are noisy, and for a fire to be this hot, he would have expected more noise.

The whole pattern was not working. His expectations were not happening as he was expecting them to. With hindsight, it was obvious that the living room was hot and silent because the flames were located below, and therefore the floor was muffling the noise of the fire. But in the heat of the moment, nothing was hinting at this. Thus the events were not typical, and his reaction was to withdraw, to regroup and to try to better understand what was going on.

The lieutenant’s experience had given a firm set of patterns. He was used to form an opinion of the situation by matching it to one of these patterns. He may not have been able to articulate these patterns to describe their particularities, but he was relying on the match with the pattern to trust in the identification of the situation he was in.

Nevertheless, he was not aware of how he was using his experience because he was not using it consciously and deliberately. He could see what he had in front of his eyes, but not what was going on behind them, so he attributed his expertise to an extra-sensory perception. He was both proud to understand that his intuition was directly derived from his experience and disappointed to understand that he had not had an extra-sensory perception.


In order to develop our intuition, we therefore need to expand our experience by being exposed to numerous difficult cases.

Chapter 5: The Power of Mental Simulation

Mental simulation is the ability to imagine people and objects consciously and to transform those people and objects through several transitions to finally picture them in a different way than at the start. It is therefore building a sequence of snapshots allowing you to picture what is going to happen.

Indeed, imagine that you have a truck, as it is pictured on the left, and that you would like it to balance on a pile of large bricks as pictured on the right, using only a jack and an unlimited number of bricks, by yourself.


How are you going to proceed?

In order to try and find a solution, you are going to imagine several mental images of the necessary steps to achieve it, evaluating the feasibility of these and picturing other steps if this one appears to be impossible.

The three first steps could thus be to lift the back of the truck with the jack, and then to slide it a pile of bricks:


Then, you could do the same at the front and slide in a pile of bricks in the middle and remove the ones at each end:


You can figure out these steps visually, or logically, but in both cases it is a mental simulation in which you are imagining a series of different steps leading to the desired result.

All human beings use this system when they have to imagine a solution to solve a problem. But mental simulations do not always work. Our brain can only partially apprehend reality, and there is therefore a limit to the variables we can take into account in a mental simulation. We sometimes forget or fail to predict one or more parameters and nothing happens the way we had expected.

In fact, according to the author and his team, we rarely construct mental simulations involving more than three factors. The limits of our working memory – the temporary memory used for our actions in the present – must be taken into account. And generally, mental simulations do not construct any more than six steps: beyond this, our working memory appears saturated and the implementation of simulations is made more difficult. We must therefore assemble our simulations within these constraints.

There are of course several ways of overcoming these constraints. If a particular topic is very familiar, we are able to gather several transitions into one unit and do likewise with the various factors to be taken into account. Moreover, with the right expertise, we are able to pick the right level of abstraction. Another way of overcoming these constraints is to write things down and draw diagrams in order to keep track of the transitions.

The problem becomes more complex when moving elements interact with each other at each step, as we must remember more elements and even the diagrams become useless as arrows start overlapping to represent these interactions.

Considering all these factors, building mental simulations no longer appears to be easy. We must be very familiar with the task we are simulating and think at the right level of abstraction. If the simulation is too detailed, it can overload our working memory, and if it is too abstract, it doesn’t help much. In fact, if we compare our brain to the powerful supercalculators in which scientists and the military invest millions of dollars, we could say that our brain has a very flexible and advanced simulation capability, and is endowed with imagination – unlike the supercalculators – but only has a very limited working memory. A computer has an enormous memory and is able to follow thousands of variables and interactions at the same time, but it is a very specialized tool and can only simulate environments for which it has specifically been programmed.

How mental simulations can fail

The greatest danger of mental simulation is that you may imagine all the evidences that are going to corroborate your estimation of the situation. Unfortunately, if you are sufficiently determined, you may never give up the idea that your mental simulation is Right and matches reality. As contradictions to your mental simulations come along, you may still continue to believe in it by imagining more and more complicated and deeper explanations.

Thus, Sir Francis Galton, at the end of the 19th century, tried an experiment in order to see if he could understand what the paranoids feel. He tried to maintain the belief according to which all the people he met were plotting against him. Two people were talking and suddenly looked at him? They were part of the plot. A horse swerves when it sees him? Even the animals are against him. Galton carried on as he could but had to give up before the day was up. His paranoid explanations were becoming so convincing that they were starting to become out of control and he was afraid for his own mental balance.

One of the reasons for this problem is that once we have constructed a mental simulation, we tend to fall in love with it. Whether we are using it as an explanation or to make predictions, once it is finished, we may lend it more credibility than it is worth, especially if we are not all that experienced in this field.

Despite these limitations, simulations allow us to make skilled decisions and to solve problems in conditions in which traditional analytical decision strategies cannot be applied.


Researchers have imagined a method to allow people to be more sensitive to the alternative interpretations of a situation. You must ask someone to give you an explanation about something, an explanation in which he will have the most extreme trust. Then tell him/her that you have a crystal ball telling you that this explanation is wrong. The crystal ball has not shown you why. The person must find out by him/herself another explanation, which will help him/her greatly see that one situation may have different explanations.

Chapter 7: Mental Simulations and Decision Making

Mental simulations are used at least three times in the RPD model:

1 – The awareness of the situation

One of the basic aspects of the RPD model is that experienced people can apprehend a situation and judge whether it is familiar or typical, or not. Often this judgment happens so quickly and so automatically that we are not aware of it.

Sometimes, however, we must try to lend a meaning to the various clues. Mental simulation is a way of giving meaning to events and to create an explanation.

The awareness of a situation can be formed rapidly, through an intuitive cross-checking of the patterns, or deliberately through mental simulation. Sometimes a situation reminds us of a previous event, and we try to use analogy to understand what is going on.

2 – Expectations

By evaluating a situation, people construct a mental simulation of the way in which the events have evolved and the way they are going to keep on evolving. The more experienced the decision makers, the clearer and more precise the expectations.

By checking if the expectations are satisfactory, the decision maker may judge the adequacy of mental simulation. The larger the difference and the more efforts needed to explain the conflicting differences, the less the decision maker will trust in his mental simulation and his diagnostic.

3 – Field of action

Someone who has apprehended a situation will be aware of several typical ways of reacting to it.

We have seen with the RPD model that a person will be able to choose the first idea coming into their head, without bothering to try other ones, especially when they are in a hurry. But few of us are impulsive enough to always act in this way and most major decisions are not made this way.

Mental simulation allows gauging various ways of reacting, by accepting them or rejecting them, one at a time, without the need to compare them. The firefighters make most of their decisions in this manner. Studies show that the great chess players do likewise. But there are certainly times for comparing options rather than evaluating them one by one. For example, researchers have shown that when airline pilots have to deviate from their route and land at a different airport, they simultaneously compare the benefits and faults of each. Although mental simulation plays a role, pilots do not use the RPD model here, because, even with restricted time, there are sometimes moments when you need to compare various options.

This method of decision-making having duly compared the advantages and disadvantages of each option is a good example of the rational choice model. Researchers have analyzed various decisions in various situations and have sorted them according to their belonging to the rational model or the RPD model:

Task Conditions

Decisions based on the RPD model

Rational Choice Strategies

Great time constraint

More likely

Greater experience

More likely

Dynamic conditions

More likely

Non quantifiable objectives

More likely

Need for a justification

More likely

Conflict Resolutions

More likely


More likely


More likely

Let’s look in more details at each line from the table. People are the most likely to use singular evaluation strategies (one at a time) when;

  • Time constraint is great. In this case, evaluating each option in comparison with the others and determining the comparison and analyzing criteria take too much time.
  • People are more experienced in this field. With experience, people have more trust in the first actions they consider being the right ones.
  • Conditions are dynamic. The necessary time and effort to implement a detailed analysis can be wasted if the conditions change.
  • When the objectives are not quantifiable. The ambiguity makes it hard to implement evaluation criteria that can be applied to all the options.

On the contrary, people are more likely to use comparative evaluation when;

  • They must justify their choice. Hierarchic authorities generally look for evidence that alternatives have been envisaged.
  • Conflict resolution is a factor. When all the conflicting parties have different priorities, it is important to find a common comparison, which can put all the expectations in a similar format.
  • The decision maker is trying to optimize in order to find the best course of action. This is fundamentally what comparison is all about. Singular evaluation is attempting to find the first acceptable, but not necessarily the best one.
  • The situation is complex. If it is something that no one can easily recognize or conceive, like analyzing an investment portfolio, to find the best strategy.
The researchers also identified and analyzed a large number of decisions in various trades, and determined the percentage of those who used the RPD model:

Surveyed trade

Number of decisions

Decisions using RPD

Urban Fire Officers



Specialized and expert Fire Officers



Novice Fire Officers



Tank Commanders



Fire Officers managing a forest fire

Functional decisions

Organizational decisions







Design Engineers



Combat squad



Ship captain AEGIS



Chapter 8: The Power to Detect the Leverage Points

This section explores the means used by people to use leverage points – a small difference that makes a big difference, a small change that can turn a situation around – in order to create a new chain reaction, and the way they are able identify what could cause problems before there are any signs of trouble.

A leverage point is a focus for building a solution. It is the starting point for an insightful problem solving. If you need to move a rock, you can lean your shoulder against it and push with all your might to counteract its enormous inertia, or you can study the rock and its environment to find the flaw which will enable you make it move or tumble. The leverage points play an important role in many fields, and there are examples galore in the business sector.

For example, the realization by Boeing engineers that commercial jet liners would have an enormous advantage over propelled airplanes was the creation of a major point of leverage. The engineers had not yet designed such a plane and they didn’t have a market for it. But they had a concept and the curiosity to find out what was going to happen if they fitted jet engines on airline planes. The rival companies such as Douglas with its DC-8 came later and were never able to commercially compete against this plane. Similarly, the very well known example of Henry Ford realizing that he could make motorcars using mass production to reduce costs so that most workers could afford his T-model, is an excellent demonstration of the discovery and use of a leverage point. Before that, Ford was only one of the thirty American car manufacturing companies fighting for a luxury and artisanal market.

Similarly, scientists, the military, sportsmen, chess players and many others need to identify and use leverage points.

Leverage points are just possibilities – pressure points that can lead to something useful, or nowhere at all. Expertise may be useful in identifying them. Experts know how recordings are compiled, be it cards, manuals, diagnostic tests or taking-off checklists. They know when you need to follow the steps and when you can make an exception.

We must also detect the leverage points that can work against us, in order to learn the weaknesses of our plans. They are sometimes called bottlenecks. By detecting them, we give ourselves time to take preventive action before an emergency situation occurs.

Note: although Gary Klein doesn’t talk about it explicitly, the leverage points are simply the 20% of action leading to 80% of results.

To be continued in the next episode .

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