Reasons Why You Make Bad Decisions, According to Science

Desiree Peralta

Knowing how your mind works may help you make better decisions in the future by Engin Akyurt from Pexels

Whether you’re considering starting a new project, or can’t decide what food to eat later, we all want to make the right decision. Making better decisions makes us more productive, more energetic, and closer to our goals. But we can’t always make the best choices.

If you look back at your life and think about a poor choice you made, you might wonder exactly why you made it. Why do we make bad decisions when we know how to do better?

Does that mean we don’t know how to do things correctly, or is it just a matter of fate? According to science, making bad decisions is completely normal and is due to a number of factors.

Throughout the day, people make an average of 35,000 decisions and we are only fully aware of a small part of them. Specifically, our brain makes 99.74% of decisions automatically, that is, without actually being aware of them.

The human brain works by mechanizing certain processes that are repeated on a daily basis, so it reduces the number of actual decisions that we have to make to about one hundred a day. This translates to just over four decisions an hour.

There are several factors that contribute to poor decisions and knowing how these processes work and influence your thinking may help you make better decisions in the future.

Our Mind Suffers from Cognitive Fatigue

Our mind works like a muscle. So we are training it with it all the cognitive processes associated with it, such as willpower, decision-making, and even just our way of thinking.

And as happens with the muscles of the body, when we use them over and over again without giving them time for their proper recovery, they tire and end up underperforming.

On a cognitive level, with every decision we make, no matter how minimal, we are consuming a portion of our mental energy.

When our mental energy is almost depleted it is much easier for our brain to go into a “survival” mode in which “no” by default is the easy option. From that cognitive survival mode, it is much easier to start making bad choices that require less effort (even though we know perfectly well what the good choices are).

Let's consider an example. In a research study conducted by Columbia University, a group of research psychologists examined 1,112 trials over a 10-month period.

These trials considered matters of probation, conducted by a specific commission appointed to personally evaluate the case of a convicted criminal and determine whether he was granted parole. Naturally, you would expect the judges of this commission to make their decision based on considerations such as the type of crime committed or what laws had been violated when making a decision.

But what the researchers found was something very different. In fact, they saw that the judges’ decisions had nothing to do with what was happening in the courtroom or with the type of case.

Instead, they were determined by the hours of the day it took for them to make a decision.

Their research indicated that in trials undergone at the beginning of the morning, a criminal had up to a 65% chance of having a favorable judgment. But as the morning progressed and the judge became “worn out” by continual decision making, those odds rapidly decreased to zero.

They found this clear trend after analyzing more than 1,100 cases over a period of 10 months. Regardless of the type of crime committed, it didn’t matter if it was rape, robbery, or embezzlement. A criminal was much more likely to be granted parole if his trial was the first in the morning, or the first after lunch, than at other times of the day.

Our Mind Uses Mental Shortcuts

In order to make decisions quickly and economically, our brains rely on a number of cognitive shortcuts known as heuristics.

They are automatic habits of thought (assumptions, inferences, hypotheses, etc.) that are triggered in our minds when we interpret our daily experiences and model them. Its role is to make sense of our experience and anticipate future events quickly.

On the one hand, they can be really useful as they make our task easier and prevent us from getting stuck when making a decision. On the other hand, simplifying problems leads us to biased conclusions.

When making decisions, the most common heuristics are the:

  • Representativeness heuristic: You make judgments to the extent that some situations resemble others. You judge the probability that a person, object, or situation belongs to a category, noting the similarity that it presents with the other members or elements of the same.

Example: Quality products are expensive, ergo expensive products are quality. This heuristic is very present in the prejudices that we have and it conditions the way in which we treat a person by categorizing them based on their sex, race, or social position.

  • Availability heuristic: We base our decisions on the information that is first and most readily available in our minds.

Example: We are more afraid of traveling by plane since air accidents have a greater impact and media coverage and therefore are more available in our memory.

  • Anchoring and adjustment heuristic: We make judgments based on an initial value that we later modify and accommodate as we obtain more information.

Example: You are going to buy and you have $100 to spend. The seller proposes a higher price than what you should spend, but when negotiating and lowering it, we are happy since the initial value was higher.

Heuristics make life easier for us. They are cognitive savings to consider. But they also make us make mistakes and therefore we have to know why and how they affect us.

One of the reasons we use them is because we don’t have the time or desire to make a decision slowly, looking at all the possible variables.

In my opinion, when you have to make an important decision, it is advisable to avoid mental shortcuts, review all the information available and take it with time and dedication.

We Often Make Poor Comparisons

The comparison is one of the major tools we use when making decisions. This happens because we want to make the best possible decision based on all the options we have.

Real comparisons are good, we stopped buying a $300 phone because there was another for $150 that does the same thing you need.

But the problem lies in poor comparisons.

According to Verywellmind, we make poor comparisons when we try to compare completely different things. Comparisons only work when we do use them with two things under the same circumstances.

For example, If you make $1000 a month, and your boss says he will raise it by $500, that would be a great thing — your salary would increase by 50%. But for someone making $10,000, if they were told they were receiving a raise of $500 — they would probably take it as an insult.

If you make a decision based on the opinions of others who do not understand your reality, it will probably go wrong.

Another example would be to buy a speaker in a store because it costs 25 dollars, and next to it there was one for 50 dollars, believing that you had a good offer, only to later realize that in Amazon it costs 10 dollars.

These types of comparisons occur because we do not investigate in detail whether a decision is worth making, and we rely on feelings of the moment.


We always want to make the “right” decision. It does not matter in what type of election. It does not matter whether it is choosing the pasta sauce that we are going to order or making a vital decision.

And if we add a large number of trivial decisions that we make throughout the day and the enormous number of options that we have available for those decisions, then we end up mentally exhausted and making poor decisions about what really matters.

So next time you have an important decision to make, first assess whether your mind is ready to make it.

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Turning ideas into reality. Programmer by profession, Writer by passion. Writing, productivity, and self-development advice.

Yonkers, NY

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