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Mental Models, Human Tendencies, and Finance

Updated: Nov 9, 2023

Saving for a great retirement requires more than facts and statistics. Numbers don’t lie but as humans, we have to watch out for what our brains tell us about those numbers. What in the world are we talking about? Human tendencies and mental models.


When we take time to see how and why we think certain thoughts, this helps us prevent mistakes. For example, Tom Brady may know an opposing defense leads the league in interceptions. But in addition to that knowledge, he can gain an advantage by knowing the thought process and tendencies of that team's defensive coordinator.

This same principle can help you earn more money and save more for retirement. In today’s fast-paced world, it is tempting to underestimate how powerful our minds are. Slowing down to consider why we are making the choices we make is a wise use of time. Tom Brady wants to avoid interceptions and increase touchdowns. As working Americans, we want to limit losses, as well as increase income and returns on investments.

So let’s look at several mental models and human tendencies to watch for so you can build wealth more safely and efficiently.

Beware These Human Habits

Confirmation Bias - This one can extend mistakes simply because we believe what we already believe. If you have said Tom Brady is the best quarterback in the NFL for 15 years then you are not likely to change your mind. Even if he declined rapidly. You're biased toward what you already think.

This tendency or human habit can come back to bite you financially in many ways. One way is if you believe your income cannot go any higher in your current industry. This can keep you from exploring more lucrative options. Also, if you’ve invested in tech stocks for ten years and saw great returns, you may be tempted to stick with them forever. Even if the internet went out of business!

Social Proof - This is human nature to go along with the crowd. It’s helpful to our historic survival. You didn’t want to be the only caveman eating the orange berries since they might kill you. But when the crowd is choosing the wrong thing you can get swept up with their decisions even when your individual instincts tell you to make different choices.

crowded street

For example, if a seller on Amazon has 2,000 five-star reviews, you will feel safe buying their product. But if half of those are fake reviews (which is still an issue online) you could be wasting your money. Another example was Bernie Madoff. So many investors got conned in this mammoth scam because they trusted the social proof of so many other investors who had already put their savings in Madoff’s hands.

First-Conclusion Bias - Watch out for this one as it could haunt you for years. This human tendency shows how we are likely to cling to the first idea that we fully accept. If you read an article about Bill Belichick being the reason Tom Brady left the Patriots, and let’s say you accept that premise. You could read ten articles disputing that and never believe those accounts. The first conclusion is tough to shake off.

Same thing happens if you start your career off working for a good company. After a couple years you accept the idea that running your own business is too risky and too much trouble. That idea is now cemented in you. And even if an opportunity comes along that could double your income as a business owner, you may turn it down without any consideration at all.

Survivorship Bias - Great one here. This bias is what has kept American Idol going for way too long. Singers with no chance waste time and money to try out because they see stars born on their TV screen. All the focus is on the singer who wins it all. Not the thousands who barely get on screen before getting booted.

You have to be careful when looking at success stories. Anyone can succeed in business. However, not everyone is going to end up like Jeff Bezos. Statistically and logically, there are only a few top spots in any business category. Even if you take the same steps as the uber-successful, that doesn’t guarantee the same outcome.

Luck and circumstances outside our control play a role. The idea with this tendency is to at least consider those who did not make it to the top. They far outnumber the one or two who did reach the pinnacle.


*Important to note though. A recent study showed similar tendencies of the wealthy which can be modeled by anyone to level up financially:

Saving and investing are part of their daily routine

They compete to climb the corporate ladder

They are paid on the extreme high end due to their expertise

Mental Models and Money Matters

Now that you know some things to watch out for when it comes to our inherent thinking, how about tools to manage these habits? Mental models can assist with any of life’s dilemmas, including financial issues.

Circle of Competence - “Stay in your lane” may sound more familiar. Any of us can learn about any topic we want to investigate. But consider this for a moment. How long did it take you to become super knowledgeable about your favorite subject? Five years? Ten?

And when it comes to investing, would you rather put your savings into something you have read about for a year or two? Or would you choose an investment you understand better than 95 percent of people in America?

This mental model would also help if you were starting a business. If you watched your father operate an insurance agency for decades then you understand micro details. Not so if you jumped into a restaurant business just because you like grilling on the weekends. You’re likely to get an education on the dos and don’ts of the restaurant world - mostly the don’ts!

*38% of Gen X and 35% of millennials have no idea how much they need to save for retirement. Luckily they can increase their circle of competence if they start learning now.

Inversion Principle - This model flips our thinking on its head, no pun intended. Instead of focusing 100 percent on the outcome we desire, we should try looking at the opposite. Which outcome would we most want to avoid?

kids on couch

This simplifies the thought process. And while it won’t provide all the answers to complex issues like retirement and career plans, it can add lots of clarity when you face a difficult decision.

Genius Not Needed to Avoid Mistakes - Another simple mental model related to the one above. This one was mentioned by Charlie Munger. But it can also be summed up in a book about tennis. A statistician found and wrote about how amateur tennis players should focus on not making mistakes. His research showed most points were a result of one player’s mistake, not a great play by the opponent. In other words, play conservatively and you should win consistently.

Yes, this model is simple. That’s what makes it so effective and available to anyone. You don’t have to make brilliant investments that wow the world. You just have to be smart, save all you can, and invest with common sense for the long haul. Avoiding major mistakes has paved the way for countless Americans to reach the retirement they deserve.

80/20 Rule - We have touched on this principle before. It is always worth revisiting because when it comes to income, saving, and investing, you want your effort to count. Generally, 20 percent of your effort produces 80 percent of your outcomes. So it’s wise to investigate which efforts are paying off, correct?

Here are three examples connected to finance:

  1. Your business spends 20 percent of the advertising budget on local ads but 80 percent of sales are from local shoppers. So. advertising more locally would be wise.

  2. Spending 80 percent of your time trying to reduce smaller household expenses prevents more focus on larger expenses that make a bigger impact (i.e. Focusing on Starbucks instead of a big car payment).

  3. Instead of five hours reading stock market reports weekly, you could spend one hour a week combing through your budget. Finding ways to save more so you can invest more is a better use of time in this case.

Opportunity Cost - When you spend time or money on one thing, you miss out on something else. You can’t go on a two-week cruise and vacation at the beach at the same time. You can’t keep running a side-hustle if you take a new job that requires you to work 20 more hours than your current job requires.

This is where decision-making is crucial. What is most beneficial to your family? On a personal level and from a financial perspective? Sometimes opportunity costs are no-brainers when you take time to look closely at the options. It’s when we make hasty decisions that we don’t see what we’re giving up in order to spend our resources elsewhere.


So how can we summarize all these aspects of our thought processes and the tactics that may help us make better choices? Mainly - be careful what you’re thinking. There are reasons behind those thoughts and why you believe them.


Some are solid truths. But you can’t be sure until you’ve paused to consider different perspectives and used various mental models that help you see from alternate angles.

Investment advice offered through Private Advisor Group, LLC, a registered investment advisor.

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