A mental model is a recurring concept that helps you think clearly and make better decisions.
There are hundreds of mental models across various fields and you might have heard most of the popular ones (Pareto principle, availability bias, anchoring, framing, loss aversion, etc.) frequently in the past few years.
But there are many other interesting models that don’t get the coverage they deserve.
Here are 21 mental models that are less popular but quite insightful.
1. Hanlon’s Razor
Never attribute to malice that which is adequately explained by carelessness
When someone does something wrong, the simplest explanation is that they were just careless. And it is often right. They took the path of least resistance and did not cause the outcome out of malicious intent.
When you send a long message to someone and they respond with just an OK, it might just be that they were busy. Don’t think that they are being dismissive/disrespectful.
2. Semmelweiss Reflex
Ignaz Semmelweiss was a 19th-century Hungarian doctor, who first proved that washing hands with a solution of chlorinated lime by doctors, drastically reduced post-operation death rates.
Despite the overwhelming evidence, the medical community dismissed his theory. He later went crazy, got admitted into an asylum, and eventually died at age 47. 20 years later, his idea of antiseptics started to be accepted, following Louis Pasteur’s germ theory.
Semmelweiss reflex is our natural tendency to stick to old beliefs and reject fresh evidence because it contradicts the existing norms.
This model is the reason many established industries are disrupted by outsiders. This kind of confirmation bias tends to be prevalent among industry veterans
3.Third Story
There are two sides to a story in any conflict between two parties. The third story is one that an impartial third-party observer would tell.
In any negotiation or disagreement, try to force yourself to think as an impartial observer. This will increase your empathy and help acknowledge others’ perspectives, whether you agree with them or not.
4.MRI
MRI (Most respectful Interpretation) asks you to explain another person’s behavior in the most respectful way.
When you see a rash driver on the road, think that he must be in an emergency and has to get somewhere urgently. This helps you remain open-minded and not be judgmental.
5.Goodhart’s Law
When a measure becomes a target, it ceases to be a good measure
When you make any measure as a target, people tend to find several ways of achieving it, not necessarily through the ideal behavior you intend to promote.
High-stakes testing like job interviews and competitive exams create a culture of “teaching to ace the particular test” rather than being an ideal screening mechanism.
6.Cobra Effect
The Cobra effect is when an attempted solution makes the problem even worse.
During the British rule of India, they were concerned about the cobra population in the country. They started a bounty program with monetary rewards to whoever brought them snakes. The policy worked well initially. But soon, people started breeding cobras for the reward.
When the British realized this and stopped the program, these cobras were released into the city, making the problem much worse.
7.Hicks Law
A greater number of choices increases the decision time logarithmically
If you want people to make quick decisions, reduce the number of choices. This is an important concept in UX design, be it web/app navigation or restaurant menus.
8.Sayre’s Law
In any dispute, the intensity of feeling is inversely proportional to the value of the issue at stake
We tend to get more emotional while debating trivial issues, and less involved when discussing important matters.
9.Parkinson’s law of Triviality
Organizations tend to give disproportional weight to trivial matters
A related concept to Sayre’s law, this shows how organizations tend to focus on the wrong things due to groupthink. In any meeting, members are often hesitant to discuss complex and important problems. In contrast, everyone weighs in on trivial matters as they are familiar and easily understood.
10.Hofstadter’s Law
It always takes longer than expected, even when you take into account Hofstadter’s law
The 90-90 rule in programming says that the first 90% of code takes 90% of development time. The remaining 10% takes another 90% time to complete.
We are bad at predicting when things get done. Projects take longer than expected, even when we expect them to take longer time.
11.Shirky Principle
Institutions will try to preserve the problem to which they are the solution
A person or department often tries to preserve an inefficient process if they are good at solving it. Even when a better idea comes around, it is dismissed and the inertia to change lingers for a long time.
12.Metcalfe’s Law
Named after the co-inventor of Ethernet, Robert Metcalfe, this model explains the exponential growth in a network’s value as more nodes are connected to each other.
These network effects work in our day-to-day lives as well. Being part of the right communities/interest groups gives you access to rare opportunities which are not accessible to outsiders. As more of the right people join those groups, the group value gets exponentially large.
13.Echo Chambers
Social media and the Internet in general give you recommendations based on your past searches/viewpoints.
They show you the stories/link that you are most likely to click on and filter out opposing viewpoints. This places you in a bubble where the same ideas get pushed to the same set of people and prevent you from having an objective point of view.
You also overestimate the number of people with views similar to yours.
14.Ultimatum Game
This is a game played by two people. The first person is given some money (say 10$) and he should offer to split the money with the second person. The second person can either accept or reject it. If he rejects, both of them get nothing.
The most rational solution is for the first person to offer a 9.99$/0.01$ split and for the second person to accept it.
In reality, though, the second person usually rejects any offer less than 30% of the total value. They would deny the first person anything, even if they themselves get nothing. This is because of the perception of fairness.
This phenomenon should be kept in mind while dealing with people and the perceived fairness of any arrangement between the two of you.
15.Joys Law
No matter who you are, most of the smartest people work for someone else
Named after Bill Joy, co-founder of Sun Microsystems, this model says that organizations can never have perfect talent. Even if they don’t have sufficient talent at the moment, they can’t wait for better employees to move forward. You got to do the best with what you have.
16.Peter Principle
Managers rise to the level of their incompetence
Employees are often promoted to higher roles based on their current performance. The new job requires a different skill set than the existing one. Eventually, they will be promoted to a role where they will be ill-suited
While promoting someone, you need to check how likely they are to grow into the new role, irrespective of their past achievements.
17.Streisand Effect
You draw more attention to something when you try to hide it
In 2003, an entertainer named Barbra Streisand sued a website for publishing a photo of her mansion, which she wanted to remain private. The image was downloaded 6 times before the suit. As the news of the suit went public, the views reached millions and it was even published on Wikipedia.
18.Spacing Effect
This model says that the retention of learning is greater when that learning is spaced out over a period of time, rather than when you cram the same amount in a shorter time.
The spacing effect works not just in learning. Ads work better when they are spaced out over time. Spacing topics within a book or article is better than a separate chapter/section for each topic. We need periodic reinforcements to really internalize anything.
19.Pygmalion Effect
Higher expectations lead to increased performance
People strive to achieve the expectations set for them. This is a form of self-fulfilling prophecy where you believe in the potential of your employees and they rise to the level of expectations set.
20.Birth Lottery
Many of us have essentially won a lottery by not being born into poverty, disability, or any other disadvantage at birth.
But when we eventually succeed at anything, we find it hard to acknowledge that a good portion of that success came from luck.
This tendency is also responsible for blaming others for their circumstances, not accounting for randomness or luck factor.
21.Dunbar’s Number
150 is the maximum group size at which a common group can be maintained
The idea is that below 150, you can easily know everyone in the group. Above 150, it is difficult to know who does what in a company.
Systems and processes that worked for below 150 will seem to be ineffective, and we need to construct fresh ones, once this number is exceeded.
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