Mental models – a secret weapon for startup founders

Mental models help startup founders avoid bias and blind spots, thus making decisions less risky. A mental model is an idea that helps you better understand the reality of the world around you. They provide shortcuts to higher-level thinking by forcing your brain to think about a problem or decision from different perspectives.

Mental models come from multiple disciplines including physics, psychology, biology, chemistry, economics, and mathematics. There are thousands of models. The good news is that about 100 models can do the heavy lifting for most decisions. The website Farnam Street provides an overview of the most beneficial 109 mental models.

All startup founders are biased, and all have blind spots. Biases are pervasive and highly resistant to feedback, and they can cause us to overlook or dismiss crucial information. Getting feedback from customers, advisors, and employees is essential to overcoming biases. However, founders are forced to make dozens of decisions a day, making it difficult to always get timely advice. Time constraints and the difficulty of finding quality information can lead smart people to make poor decisions.

In the summer of 2016, I went through the startup accelerator Y Combinator (YC). One of the most valuable aspects of that experience was called “office hours.” During office hours I had an opportunity to meet with a YC partner and get feedback about a specific problem or decision. I gained new insight as the partner helped me view my problem through a different lens.

Mental models can function like a YC partner or advisor by forcing you to see a problem from a different perspective. They teach us how to think better. Models can also provide your team a common vocabulary and stimulate useful discussion when you are facing important decisions. Investing time to learn and operationalize these models will help you and your team improve your decision-making process.

Here are a few of the mental models I find most useful.

Hanlon’s razor

Don’t attribute malice or bad intent to actions or outcomes that could be explained by carelessness, busyness, or ignorance. Give people the benefit of the doubt.

Use when: A customer is not returning your call. A colleague missed an important internal meeting without informing you in advance. A new potential partner didn’t sign and return the partnership agreement by the agreed timeline.

Thinking gray

Delay forming an opinion until you have reviewed all the important facts and heard from all key stakeholders. This technique is useful to overcome confirmation bias, which is our tendency to search for, interpret, and favor information that confirms our pre-existing beliefs and desired outcome.

Use when: Designing a go-to-market strategy. Identifying the target audience for a marketing campaign. Determining which features should be prioritized on the product roadmap.

Five whys

This model forces you to push through your intuition and optimism to reveal the underlying truth. Keep repeating the question “Why did this happen?” or “Why do we need this?” at least five times to reveal the root cause of the problem.

Here is an example from the book Super Thinking – The Big Book of Mental Models. The example shows how this mental model was used to identify the root cause of the Space Shuttle Challenger explosion.

1. Why did the Challenger’s hydrogen tank ignite? Hot gases were leaking from the rocket motor.

2. Why was the hot gas leaking? A seal in the motor broke.

3. Why did the seal break? The O-ring that was supposed to protect the seal failed.

4. Why did the O-ring fail? It was used at a temperature outside its intended range.

5. Why was the O-ring used outside its temperature range? Because on launch day, the temperature was below freezing, at 29 degrees Fahrenheit. (Previously, the coldest launch had been at 53 degrees.)

6. Why did the launch go forward when it was so cold? Safety concerns were ignored at the launch meeting.

7. Why were the safety concerns ignored? There was a lack of proper checks and balances at NASA. That was the root cause, the real reason the Challenger disaster occurred.

Use when: Conducting postmortems to determine why a project or product failed. Deciding to create and hire a new role in the company. Designing new human resource processes or procedures.


Flip a problem around and approach it from the opposite end of the natural starting point. Instead of starting at the beginning and thinking forward, start at the end and think backward. This allows you to identify and remove obstacles to success.

Use when: Designing a user experience for a new product. Creating the onboard experience for new employees. Identifying the best strategy to sell a target customer.

Eisenhower decision matrix

This model employs a two-by-two grid (matrix) that helps you prioritize based on urgency and importance. Stephen Covey, author of 7 Habits of Highly Effective People, was inspired to create the matrix below based on U.S. President Dwight Eisenhower’s quote, “What is important is seldom urgent and what is urgent is seldom important.”

Examples of when, how to use

 UrgentNot Urgent
Important    I. – Manage  
Meeting customer deadlines
Resolving key employee issue
Fixing web server problem  
II. – Focus  
Developing strategic plan
Building relationships
Deep work
Not Important    III. – Triage  
Last-minute meeting requests
Most events

IV. – Avoid  
Most conferences
Most things that distract from focus on
customers and product

Opportunity cost

Every choice you make carries a cost. Choosing to do one thing means choosing not to do another. Identify multiple scenarios and evaluate the costs of each before committing. Select the one with the lowest opportunity cost.

Use when: Building a new product feature. Deciding whether to attend a conference. Determining which customer to target.


Mental models help us avoid bias and blind spots and de-risk our decisions. They teach us to think clearly. Investing time to learn several models will help you and your team improve your decision-making process and make fewer wrong calls. To learn more about this process, take a look at my post, “Avoid Blind Spots and Make Smarter Decisions.”

To learn more about mental models, I recommend the following:

Super Thinking – The Big Book of Mental Models by Gabriel Weinberg and Lauren McCann

The Great Mental Models: General Thinking Concepts by Shane Parrish

Poor Charlie’s Almanack – The Wit and Wisdom of Charles T. Munger edited by Peter Kaufman


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