Gambler’s Fallacy

Our brains have to make a lot of decisions quickly: whether we want to cross the street, leave our jobs, or bet on red or black. But biases and fallacies like the gambler’s fallacy, cloud our judgment and may lead us astray. 

What Is The Gambler’s Fallacy? 

The gambler’s fallacy is a bias in which we let past events influence our decisions and predictions about what will happen next. But this bias is based on fallacy, or a mistaken belief. Each action is independent of the actions before it. 

In roulette, a ball has a 50/50 chance of landing on black every single time you play roulette. Many people, however, believe that if it lands on black once, it will land on red next. Sure, the chances of the ball landing on black 26 times in a row are way smaller than the chances of the ball landing on black twice or three times in a row, but that doesn’t mean that the ball will land on red based on those chances. 

a man using the gambler's fallacy

Is Gambler’s Fallacy Real?

In 1913, gamblers at the Monte Carlo Casino lost millions of francs at the roulette table. The ball would land on black, and the gamblers would bet on red. The ball would land on black again, and the gamblers would continue to bet on red. 

The ball landed on black 26 times in a row. The probability of that happening was 1 in 66.6 million. To this day, it’s a shocking moment in gambling history. 

Put yourself in the gamblers at Monte Carlo’s shoes. The ball lands on black. The ball lands on black again. The ball lands on black for a third, fourth, or fifth time. 

At some point, you’re going to feel sure that the ball will land on red next. There’s a 50/50 chance that the ball will land on red at any given time or on black at any given time. So after a streak of the ball landing on black, you may start to think that the ball has to land on red next. 

The 27th time, can you guess what the probability of the ball landing on black would be? 

1 in 2, or 50/50. 

This doesn’t seem right, but it is. And the people who would have bet on black, after the ball landing on black 26 times in a row, would still only win double what they bet. 

More Examples of the Gambler’s Fallacy 

Other Casino Games

The gambler’s fallacy often leads people astray while they’re in the casino. Think of all of the people who continued to bet on red at Monte Carlo. I’m sure some of those gamblers put a lot of money on red, thinking that somehow their chances at winning big were larger just because the ball kept landing on black. 

But this doesn’t just happen at the roulette table. Many people will stay at the slots for hours, believing that although they lost time after time again, their chances of winning will somehow increase.

slot machine

The gambler’s fallacy isn’t just a phenomenon that occurs within the walls of a casino. In the “real world,” this logical fallacy can have some pretty serious effects on the ways people make decisions and conduct business. 

Financial Gambles 

Take loans. Approving or rejecting loans can sometimes feel like a gamble to loan officers. Studies show that loan officers are more likely to reject a loan that is sitting in front of them if they had approved the last loan that came across their desk. Researchers think that 5% of loans are affected by this fallacy.

This can have a huge impact on a person’s ability to buy a house or start a business, but further research shows that this fallacy can have an even more significant impact.

Legal Gambles 

Asylum judges are not immune to the gambler’s fallacy. Data shows that they are more likely to approve a person’s application if they had denied the previous application, and vice versa.  

How to Explain the Gambler’s Fallacy 

The gambler’s fallacy goes beyond how we make decisions – some argue that it affects how we make sense of the world. Remember, the gambler’s fallacy is a bias that is influenced by past events. We may link our decision to stay at the slots because of past events. But we may also explain what is happening now based on what happened in the past. 

We use the gambler’s fallacy to establish patterns. We may get sick and blame it on the bread that we ate before. If we get sick a second time after eating bread, we are very likely to believe that we have an intolerance or allergy involving gluten. But connecting our stomachache to what we ate before isn’t always based in logic or correct probability. Just like connecting the ball landing on red to the ball landing on black before (or vice versa) isn’t always based in logic. Independent events are just that – independent events. 

How to Avoid The Gambler’s Fallacy 

I’m not saying that people with stomach aches shouldn’t write off certain foods or that you should go to the casino and only bet on one color or number. But I am telling you about the gambler’s fallacy so you can be more aware of if you’re using it in your life. 

Logical fallacies and biases affect the way we make decisions, form arguments, and predict what is going to happen in the future. Since these fallacies are based on falsehoods, the results may not be so great. The more you are aware of these logical fallacies and biases, like the confirmation bias or experimenter bias, the easier it will be for you to step back, make a proper assessment based on facts, and make better sense of what is going on around you. 

Sunk Cost Fallacy vs. Gambler’s Fallacy 

sunk-cost fallacy

The sunk-cost fallacy and gambler’s fallacy are often confused, but they are quite different. The sunk-cost fallacy leads us to follow through with decisions we have already “paid” for. Gambler’s fallacy leads us to make decisions based on past results, whether or not we had “paid” for them. You can fall into the trap of gambler’s fallacy, for example, by betting on red after a ball landed on black, whether or not you lost money in the previous spin. 


Let’s test your knowledge on the Gambler’s Fallacy. 

Question 1: 

A coin has been flipped 12 times. 10 of those flips have resulted in “heads.” What is the likelihood that it’s going to be tails the next time you flip it? 



Question 2: 

True or False: The Gambler’s Fallacy is just limited to gamblers. 


False. Everyone is affected at some point by the Gambler’s Fallacy. It’s a common bias that all humans experience. 

Last question: 

The Gambler’s Fallacy is a _____ fallacy that we should be aware of when making judgements and decisions. 



Practical Psychology

Practical Psychology began as a collection of study material for psychology students in 2016, created by a student in the field. It has since evolved into an online blog and YouTube channel providing mental health advice, tools, and academic support to individuals from all backgrounds. With over 2 million YouTube subscribers, over 500 articles, and an annual reach of almost 12 million students, it has become one of the most popular sources of psychological information.

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