This post departs from the rationalistic school to the naturalistic school of decision-making, where assumptions of rationality are thrown out of the window.

We’ve discussed at length about rational choice theory (Part 1 and Part 2). So far, I’ve come to the conclusion that rational choice theory is kind of detached from reality and tends to ignore the small things that make us human such as our habits, culture, etc.

Now, we visit the naturalistic decision-making (NDM) school that has a different set of core assumptions. Also known as “recognition-primed decision-making” (RPD for short), this school of decision-making believes that the rationalistic approach does not hold when humans are observed in a “natural” setting, such as in a real crisis or actual wartime setting.


Gary Klein


One of the prominent thinkers in the NDM school is Gary Klein [PDF]. In his work, Klein observes the behaviour of firefighters in a “naturalistic” setting. By “naturalistic”, Klein refers to a real-life circumstance where a firefighter would expect to be in action; when a house is on fire (see Klein et al., 2010 [paywall])

Through observing the behaviour of people in a real-as-possible situation, Klein argues that most of the tenets of the rationalistic approach do not hold.

But first, what is a “natural” setting? Related to war or any other possibly life-threatening situation,  a “natural” setting can be one that is rife with uncertainty, ill-defined objectives, information deficiency, stress, and dynamically changing situations. When the stakes are unknown and you’re pressed for time, you can’t possibly be expected to act according to the rationalist assumption.

The situation was as follows. A captain led his team inside a burning house. The captain went to the kitchen, where the fire was thought to originate. However, he only saw smoke; no fire. Feeling that something was wrong, the captain called his men to retreat. Just as they left the kitchen, the entire kitchen floor then collapsed, revealing that the fire was in the basement.

When Klein asked the captain about his decision, the captain told Klein that he made that decision based on his intuition. The captain didn’t stop to make any ranked preferences and plot possible alternative actions. Instead, the captain just decided to trust his gut and go with the first option available to him.

Thus, the naturalistic decision-making school was born.

NDM puts heavy emphasis on “expertise”. Serfaty et al. [e-book] stressed the importance of a “mental model”, which supposedly helps people make decisions. The reason an expert is an expert is because they have a different mental model from “normal” people. This refined mental model then helps them in stressful, information-deficient, and uncertain environments. For example, a seasoned war veteran would adopt a different course of action compared to that of an FNG. Or, in terms that I can relate to, a seasoned gamer would make decisions differently from a new gamer, simply because the former is more experienced.


But what is a mental model? As Serfaty et al. explains, a mental model is an “internal representation of the external world” which is largely based on a “database” of past experiences and doctrine. The mental model helps the decision-maker to assess the situation, identify the necessary elements that are required for success, and map out a course of action that is worthy to be implemented in that specific situation.


RPD model.jpg
Source: Klein


This is a representation of how the mental model works. The decision-maker:

  1. Experiences the situation (“recognises” the situation)
  2. Draws from their database of past experiences and expertise
  3. Seeks to “match” their expertise with the situation at hand
  4. If there’s a match, the decision-maker then implements their decided course of action.
  5. If there’s no match, the decision-maker will either modify their course of action or refrain from taking action until further information is gathered.

So, how do the decision-makers know their decision is the best from the possible alternatives? The short answer is they don’t. The NDM school believes that decision-makers don’t seek the best outcome, but they satisfice for the best possible decision within the given situation.

It’s interesting to note that when a “matching” process fails, the decision-maker presumably reverts to “slower thinking” (see Kahneman [book]) and begins to assess the situation as the rationalist would assume. This would suggest that NDM might not be as critical of the rationalist approach as previously thought.

Of course, no theory is without flaws. Though I find the NDM school rather enticing, there are several drawbacks that the school has. First of all, the central assumption of expertise is still nebulous and often lacks a rigid definition. Who is an “expert”? In the military, a General is expected to be more of an expert than a Private. However, as time changes and as warfare changes, perhaps a Private may be more well-versed in digital warfare. Similarly, the conditions of which one is called an expert is subjective. Often, Klein refers to peer judgment. If among other peers of the same profession a person is judged to be an expert, then the person is an expert.

Furthermore, there’s the issue of translating experience into expertise. The specific workings of the mental model still remain unclear. Say that an expert is well-versed in the art of strategic studies. The person has a clear understanding of the theories and their application. However, would that person still be an expert if put in a real crisis situation? Perhaps no. This means that the person’s mental model is ill-equipped to address the new situation. Once again, this stems from a lax definition of what “expertise” truly is.

The bells ring…

A quick recap:

  • The NDM school focuses more on the individual making decisions in a naturalistic setting, where the stakes are high and information is not readily available. This differs from the rationalistic approach that tends to assume that everyone is already rational in the first place.
  • The NDM school places large emphasis on expertise, though the idea itself is still rather ill-defined and subject to debate. Experts make better and faster decisions simply because they have more experience.