Mental Models

“One can train a man so that he has at his disposal a list or repertoire of the possible actions that could be taken under the circumstances…A person who is new at the game does not have immediately at his disposal a set of possible actions to consider, but has to construct them on the spot, …a time-consuming and difficult mental task…The decision maker of experience has at his disposal a checklist of things to watch out for before finally accepting a decision.”

“A large part of the difference between the experienced decision maker and the novice in these situations is not any particular intangible like “judgment” or “intuition”…If one could open the lid, so to speak, and see what was in the head of the experienced decision-maker, one would find that he had…at his disposal…repertoires of possible actions; that he had…checklists of things to think about before he acted; and that he had mechanisms in his mind to evoke these, and bring these to his conscious attention when the situations for decisions arose.”

“Most of what we do to get people ready to act in situations of encounter consists of drilling these lists into them sufficiently deeply so that they will be evoked quickly at the time of the decision.” – Herbert Simon

The ideal way to approach mental models is through simplicity. Simplicity is a very powerful construct: “Our Life is frittered away by detail…simplify, simplify” – Henry David Thoreau

Initially, reductionism will be key. Once this has established a solid base for understanding the big ideas of various subjects, moving towards a holistic approach will lead to optimal results.

Here is a brief description of mental models (wiki), to get you started. I highly recommend reading Latticework by Robert G. Hagstrom to get started.


A mental model is a kind of internal symbol or representation of external reality, hypothesized to play a major role in cognitionreasoning and decision-makingKenneth Craik suggested in 1943 that the mind constructs “small-scale models” of reality that it uses to anticipate events.

One example is provided in the following description from Richard Feynman:

I had a scheme, which I still use today when somebody is explaining something that I’m trying to understand: I keep making up examples. For instance, the mathematicians would come in with a terrific theorem, and they’re all excited. As they’re telling me the conditions of the theorem, I construct something which fits all the conditions. You know, you have a set (one ball) – disjoint (two balls). Then the balls turn colors, grow hairs, or whatever, in my head as they put more conditions on. Finally they state the theorem, which is some dumb thing about the ball which isn’t true for my hairy green ball thing, so I say, ‘False!’

Jay Wright Forrester defined general mental models as:

“The image of the world around us, which we carry in our head, is just a model. Nobody in his head imagines all the world, government or country. He has only selected concepts, and relationships between them, and uses those to represent the real system.”

In psychology, the term “mental models” is sometimes used to refer to mental representations or mental simulation generally. At other times it is used to refer to mental models and reasoning and to the mental model theory of reasoning developed by Philip Johnson-Laird and Ruth M.J. Byrne.


The term is believed to have originated with Kenneth Craik in his 1943 book The Nature of ExplanationGeorges-Henri Luquet in Le dessin enfantin (Children’s Drawings), published in 1927 by Alcan, Paris, argued that children construct internal models, a view that influenced, among others,Jean Piaget.

Philip Johnson-Laird published Mental Models: Towards a Cognitive Science of Language, Inference and Consciousness in 1983. In the same year, Dedre Gentner and Albert Stevens edited a collection of chapters in a book also titled Mental Models.[1] The first line of their book explains the idea further: “One function of this chapter is to belabor the obvious; people’s views of the world, of themselves, of their own capabilities, and of the tasks that they are asked to perform, or topics they are asked to learn, depend heavily on the conceptualizations that they bring to the task.” (See Mental Models (Gentner-Stevens book).)

Since then there has been much discussion and use of the idea in human-computer interaction and usability by researchers including Donald Norman and Steve Krug in his book Don’t Make Me Think. Walter Kintsch and Teun A. van Dijk, using the term situation model (in their bookStrategies of Discourse Comprehension, 1983), showed the relevance of mental models for the production and comprehension of discourse.

Mental models and reasoning

One view of human reasoning is that it depends on mental models. On this view mental models can be constructed from perception, imagination, or the comprehension of discourse (Johnson-Laird, 1983). Such mental models are akin to architects’ models or to physicists’ diagrams in that their structure is analogous to the structure of the situation that they represent, unlike, say, the structure of logical forms used in formal rule theories of reasoning. In this respect they are a little like pictures in the “picture” theory of language described by Ludwig Wittgenstein in 1922. Philip Johnson-Laird and Ruth M.J. Byrne developed a theory of mental models which makes the assumption that reasoning depends, not on logical form, but on mental models (Johnson-Laird and Byrne, 1991).

Principles of mental models

Mental models are based on a small set of fundamental assumptions, which distinguish them from other proposed representations in the psychology of reasoning (Byrne and Johnson-Laird, 2009). Each mental model represents a possibility. A mental model represents one possibility, capturing what is common to all the different ways in which the possibility may occur (Johnson-Laird and Byrne, 2002). Mental models are iconic, i.e., each part of a model corresponds to each part of what it represents (Johnson-Laird, 2006). Mental models are based on a principle of truth: they represent only those situations that are possible, and each model of a possibility represents only what is true in that possibility according to the proposition. Mental models can represent what is false, temporarily assumed to be true, e.g., in the case of counterfactual conditionals andcounterfactual thinking (Byrne, 2005).

Reasoning with mental models

People infer that a conclusion is valid if it holds in all the possibilities. Procedures for reasoning with mental models rely on counterexamples to refute invalid inferences; they establish validity by ensuring that a conclusion holds over all the models of the premises. Reasoners focus on a subset of the possible models of multiple-model problems—often just a single model. The ease with which reasoners can make deductions is affected by many factors, including age and working memory (Barrouillet, et al., 2000). They reject a conclusion if they find a counterexample, i.e., a possibility in which the premises hold, but the conclusion does not (Schroyens, et al. 2003; Verschueren, et al., 2005).


Scientific debate continues about whether human reasoning is based on mental models, formal rules of inference (e.g., O’Brien, 2009), domain-specific rules of inference (e.g., Cheng & Holyoak, 2008; Cosmides, 2005), or probabilities (e.g., Oaksford and Chater, 2007). Many empirical comparisons of the different theories have been carried out (e.g., Oberauer, 2006).

Mental models in system dynamics


A mental model is generally:

  • founded on hardly qualifiable, impugnable, obscure, or incomplete facts
  • flexible – is considerably variable in positive as well as in negative sense
  • effects as information filter – causes selective perception, perception of us only selected parts of information
  • compared with the complexities surrounding the world is very limited and even when the model is extensive and in accordance with a certain reality in the derivation of logical consequences of it we are very limited. We must take into account such restrictions on working memory—i.e. well-known rule on the maximum number of elements that we are suddenly able to remember, gestaltismus or failure of the principles of logic, etc.
  • source of information, which can not find anywhere else are available at any time and can be used, if other routes are possible, which is linked with the fact that it is not always clearly understood by the other and the process of interpretation can be interpreted in different ways[2][3][4]

Mental models are fundamental to understanding organizational learning. Mental models are “deeply held images of thinking and acting.”[5] Mental models are so basic to our understanding of the world that we are hardly conscious of them.

One Response to “Mental Models”

  1. Eric, just having another read of your blog, I’m once again blown away by the bredth and depth of your knowledge man! great read.

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