49+ Examples of the Thomas Theorem (Description + Critiques)

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Imagine this: You're at school, and there's a rumor that a pop quiz is happening today. You start to worry, feeling sure you're going to fail. When the quiz paper lands on your desk, your hands are sweaty, and you blank out—even though you've studied the material!

Your belief about failing didn't just make you nervous; it actually made it harder for you to remember what you learned.

This real-world magic trick is what sociologists W. I. Thomas and Dorothy Swaine Thomas talked about way back in 1928. They came up with something called the Thomas theorem.

The Thomas Theorem says, "If people believe something is real, then it's real in what it makes happen." In simpler terms, how we think about things can really change what ends up happening.

In this article, we're going to dive into this fascinating idea and explore some mind-blowing examples that show how powerful our beliefs can be.

From the tricks our minds play on us in medicine, to the ways teachers' beliefs about students can shape their futures, the Thomas theorem helps us understand the hidden forces that make our world what it is.

What is the Thomas Theorem?

red pill or blue pill

Have you ever heard the saying, "Seeing is believing"? Well, William Iasaac Thomas and Dorothy Swaine Thomas, a pair of really smart sociologists, flipped that saying on its head.

In 1928, they introduced the world to the Thomas theorem, which basically tells us that "believing is seeing." Confused? Don't worry, we'll break it down!

The Thomas theorem says: "If men define situations as real, they are real in their consequences." What this means is that if you believe something strongly enough, it can affect what actually happens.

Let's say you think you're bad at math. If you keep thinking that way, you might stop trying to get better, which makes you perform poorly in math class. So your belief turns into reality!

Now, who came up with this cool idea? The people behind this groundbreaking thought were W. I. Thomas and Dorothy Swaine Thomas.

They were a husband-and-wife team of sociologists—that's the science of studying societies and human behaviors. And guess what? They came up with this idea way back in 1928! Imagine how different the world was back then—no smartphones, no social media, but the power of belief was just as strong.

So why is this theorem so important? Well, it helps us understand how our personal beliefs, and even society's beliefs, can shape how we act, what choices we make, and even what kind of opportunities come our way.

It's a big deal because it shows us that our thoughts and perceptions aren't just "in our heads"—they can actually change the world around us.

Basic Example of the Thomas Theorem

Okay, let's roll up our sleeves and dig a little deeper into what this Thomas theorem is all about. We've already said that if you believe something is real, then it's real in what happens next. But what does that really mean? Let's break it down with a fun example.

Imagine you're in a forest, and you think you see a snake on the ground. Your heart starts to race, and you jump back. Maybe you even climb a tree!

Whether that object on the ground is a snake or just a twisted stick, your reaction is real—you really do feel scared, and you really do climb that tree. Your belief that it might be a snake has real consequences: a racing heart and an unplanned tree-climbing adventure.

So, there are two main parts to the Thomas theorem. The first part is the "definition," or how you see a situation. In our example, you defined that thing on the ground as possibly being a snake.

The second part is the "consequences," or what happens because of your belief. You felt scared, and you climbed a tree. Those are the consequences of believing you saw a snake, even if it was just a stick.

What's really cool about the Thomas theorem is that it shows us that our thoughts aren't just something that stay locked up in our heads. They step out into the world and dance around, affecting what we do and what happens to us. It's like your mind has superpowers that can shape your own little piece of the world!

And guess what? This doesn't just happen with you alone. When lots of people believe something, it can change whole communities, or even the entire world! That's a lot of power packed into what we think and believe.

Historical Context

So, now that we've talked about what the Thomas theorem is, let's hop into our time machine and go back to the year 1928.

Picture this: no TikTok, no video games, not even color TV! But guess what was around? Smart people thinking big thoughts, like W. I. Thomas and Dorothy Swaine Thomas.

These two were like the Sherlock Holmes and Dr. Watson of sociology, trying to solve the mysteries of human behavior. And when they came up with the Thomas theorem, it was like they found a hidden treasure map of the mind.

Why was their idea so groundbreaking? Well, back in the day, a lot of folks thought that what happens in the world was all about hard facts and rules, like gravity pulling an apple to the ground. But the Thomases said, "Hold on a minute! Our beliefs and thoughts can also be a big deal!"

This was super cool because it told people that the power of belief isn't just something you read about in fairy tales. It's real, and it shapes our lives every single day.

Since then, lots of other people have used the Thomas theorem to study all kinds of things: why people buy certain brands, how rumors can spread like wildfire, and even why countries go to war. Its impact has rippled through time, changing the way we understand not just individuals, but whole societies.

So the next time you think your thoughts don't matter, remember that back in 1928, two clever sociologists showed the world just how much they do!

Examples of the Thomas Theorem

tree that looks like a snake

1. The Placebo Effect

In medical trials, some patients given sugar pills instead of actual medicine report feeling better. They believe they're taking a real medication, so their body reacts as if it's healing.

2. Stereotype Threat

Some students perform worse on tests because they're aware of stereotypes that people like them are not good at subjects like math. Their fear of confirming the stereotype affects their performance.

3. Self-Fulfilling Prophecy in Relationships

If you believe someone doesn't like you, you might act distant or unfriendly toward them. In turn, they may start disliking you because of your behavior, making your original belief come true.

4. Investor Behavior in Stock Markets

If investors think a company will perform well, they buy its stocks. The increased demand drives up the stock price, making the company more valuable, thus confirming their belief.

5. Moral Panics

When communities believe something is a severe threat, like comic books corrupting youth in the 1950s, real actions like bans or regulations occur, impacting the publishing industry.

6. Sports Superstitions

Some athletes believe that wearing "lucky socks" helps them perform better. This belief boosts their confidence, often improving their actual performance in the game.

7. Classroom Dynamics

If a teacher believes a student is gifted, they may offer more challenges and encouragement, helping the student to excel and confirming the teacher's initial belief.

8. Bank Runs

If people believe a bank is unstable, they'll rush to withdraw their money. The sudden withdrawals can actually cause the bank to collapse, making the belief real.

9. Political Campaigns

If polls show that a candidate is leading, more people might vote for them because they like to back a winner. This boosts the candidate's numbers, confirming the polls.

10. Social Media Influencers

If people believe someone is influential online, more people follow them, which actually increases their influence.

11. Fear of Flying

People who are afraid of flying may become so anxious that they experience real physical symptoms like nausea, making their fear of flying more justified in their eyes.

12. Talent Shows

Someone told they have singing talent might practice more, receive more support, and actually become a great singer, validating the initial belief in their talent.

13. Job Interviews

If you believe you're unqualified for a job, you might appear nervous during the interview, reducing your chances of getting hired, thus confirming your belief.

14. Fashion Trends

When people believe a particular style is fashionable, they buy those clothes. The increased demand validates the belief that it's a trend.

15. The Y2K Bug

The widespread belief that computers would crash at the turn of the millennium led to massive spending on software upgrades, preventing the anticipated problems.

16. Gentrification

If residents believe a neighborhood is "up-and-coming," they might invest in property there, driving up property values and attracting wealthier residents.

17. Health Fads

When people believe a certain diet is healthy, they may experience weight loss and attribute it to the diet, whether or not it's scientifically proven.

18. Racial Profiling

If police believe a specific racial group is more likely to commit crimes, they may focus more on those communities, leading to higher arrest rates that seem to "confirm" the belief.

19. Online Reviews

If a product has good reviews, people are more likely to buy it. Increased sales can lead to even more positive reviews.

20. Language Barriers

Believing you're bad at learning languages can affect your ability to learn, making it difficult to pick up a new language and confirming your belief.

21. Phobias

If someone believes spiders are dangerous, they may react fearfully upon seeing one, causing stress and perhaps even attracting attention, which reinforces their fear.

22. Positive Affirmations

Repeating positive statements about oneself can lead to increased confidence and better performance, making the affirmations seem true.

23. Pygmalion Effect

In a workplace, if bosses believe certain employees are high-performers, they may give them more responsibilities, which can lead to actually improved performance.

24. Body Language

Believing you're confident can affect your posture and facial expressions, making others perceive you as confident too.

25. Religious Beliefs

If you believe in a higher power that protects you, you may take risks you otherwise wouldn't, and if those risks pay off, it may strengthen your religious convictions.

26. Urban Legends

A community's belief in an urban legend like Bigfoot may lead to reported sightings and even tourism, making the legend seem more real.

27. Fandoms

If fans believe that their support can help a movie succeed, they may buy more tickets and merchandise, contributing to the movie's success.

28. Marriage Expectations

If you enter marriage thinking it will be challenging, you may work harder to resolve conflicts, leading to a strong marriage and confirming your belief that effort matters.

29. Nationalism

Belief in national superiority can lead to investments in the military, scientific achievements, and a strong economy, seemingly confirming the belief.

30. Astrology

If you believe your zodiac sign determines your personality, you might exhibit traits associated with that sign, making it seem as if astrology is accurate.

31. Imposter Syndrome

Believing you're not competent in your role can lead to stress and poor performance, reinforcing your initial feelings of inadequacy.

32. Brand Loyalty

Belief in the quality of a certain brand can lead to repeated purchases and positive reviews, boosting the brand's reputation.

33. Cultural Taboos

If a culture believes a certain food is taboo, fewer people eat it. The absence of that food in the culture reaffirms its taboo status.

34. Housing Markets

If people believe property values will rise in a specific area, they are more likely to invest, driving up prices and confirming the initial belief.

35. Eco-friendly Practices

Belief in the importance of sustainability can lead to eco-friendly choices, contributing to environmental preservation.

36. Youth Sports

Young athletes who believe they're good at a sport may practice more, get better coaching, and actually become skilled, validating their belief.

37. Political Protests

If people believe their protests can lead to change, they are more likely to participate, and the larger the protest, the more likely it is to effect change.

38. Celebrity Endorsements

If people believe a product is good because a celebrity endorses it, sales may increase, confirming the effectiveness of celebrity endorsements.

39. Social Conformity

Belief in the importance of social norms can lead people to conform, reinforcing the idea that these norms are universally accepted.

40. Popular Vacation Spots

If people believe a location is a fantastic vacation spot, more will visit, leading to improved amenities and confirming its status as a great place to visit.

Thomas Theorem in Pop Culture


By now, you probably realize that the Thomas theorem isn't just for stuffy classrooms or scientific studies. It's everywhere, even in the movies we watch, the shows we binge, and the books we can't put down!

Let's take a look at some pop culture moments where the Thomas theorem steals the show.

1. "Harry Potter" Series

Remember the Mirror of Erised that shows what you most desire? Harry believes it's showing him his real family, and because of that, he keeps going back to the mirror night after night. His belief shapes his actions, just like the Thomas theorem says!

2. "The Matrix"

In this sci-fi classic, Neo has to believe he's "The One" to unlock his full potential. His belief in himself turns him into the hero he becomes. Believing is seeing, right?

3. "Spider-Man"

Peter Parker initially believes he can only be a hero if he hides behind a mask. This belief shapes his actions as Spider-Man, affecting how he interacts with those around him and how he fights crime.

4. "Mean Girls"

Cady Heron starts believing she has to be mean to be popular. This belief has real consequences—she becomes a person she doesn't like, hurting her friends and herself in the process.

5. Reality TV Shows

Shows like "American Idol" or "The Voice" often feature contestants who believe they can become stars. This belief drives them to audition and, for some, turns them into actual celebrities!

6. "The Wizard of Oz"

Dorothy believes she has to find the Wizard to return home. Her belief sets her on a quest that changes her life and the lives of her friends.

7. Social Media Challenges

Ever notice how quickly challenges go viral? When people believe something is fun or meaningful, they participate, making it a cultural phenomenon.

8. "Star Wars"

Luke Skywalker believes he can become a Jedi and defeat the Empire. This belief shapes his actions, training, and decisions throughout the series, making him a real hero.

9. "The Little Engine That Could"

This children's story is all about believing in yourself. The Little Engine believes he can climb the hill, and because of that belief, he actually does it!

10. "Black Panther"

King T'Challa believes in the goodness and uniqueness of his people and land. This belief has real-world consequences as it influences his decisions to open Wakanda to the world.

See? The Thomas theorem is more than just a smart idea from almost 100 years ago. It's a part of our everyday lives, shaping our stories, our heroes, and even our hashtags. The next time you're watching your favorite show or reading a thrilling book, see if you can spot the Thomas theorem in action!

Criticisms and Limitations

As cool as the Thomas theorem sounds, not everyone is head over heels for it. Just like how some people might not like chocolate ice cream (hard to believe, right?), some scholars and thinkers say the Thomas theorem has its drawbacks. Let's dive into some of the criticisms.

Oversimplification: Some critics argue that the Thomas theorem is too simple. Dr. Emily Martin, an anthropologist, says that human behavior can't be boiled down to just beliefs and reactions. Our minds and societies are way more complicated!

Ignoring Structural Factors: Sociologists like Pierre Bourdieu argue that the Thomas theorem overlooks structural issues like poverty, race, and class. So while you might believe you can be anything, societal factors can still limit your opportunities.

Cultural Differences: Dr. Geert Hofstede, known for his work on cultural dimensions, says that the Thomas theorem might not apply the same way in every culture. For example, collective beliefs in communal societies might have different effects compared to individualistic ones.

The "Chicken or Egg" Problem: Which comes first: the belief or the situation? Critics like Dr. Karen Cerulo, who studies cognition and culture, question whether the Thomas theorem can answer this. Sometimes, real circumstances might shape our beliefs, not the other way around.

Rational Choice Theory: Economists and sociologists like Gary Becker say that people make choices based on rational calculations, not just beliefs. So even if you believe something is true, you might act differently if it's not the logical thing to do.

Emotion Over Belief: Psychologists like Dr. Paul Ekman, known for studying emotions, argue that sometimes emotions can override beliefs. You might believe you shouldn't be scared of spiders, but still scream when you see one!

Exaggerating Individual Agency: The Thomas theorem focuses a lot on individual beliefs, but critics like sociologist Anthony Giddens argue that large systems, like governments or corporations, also shape reality in ways individuals can't control.

Lack of Empirical Evidence: Some critics, like Dr. Sally Haslanger, point out that the Thomas theorem isn't always backed by concrete evidence. Sure, it's a neat idea, but where's the data to prove it always works?

Ethical Concerns: Ethicists like Dr. Martha Nussbaum question the moral implications of the Thomas theorem. If a harmful belief becomes real through action, does that make it okay? Definitely something to think about.

Situational Specificity: Finally, critics like sociologist Dr. Elijah Anderson argue that the Thomas theorem might not apply in all situations. Some moments in life are so unique that beliefs alone can't shape the outcome.

So there you have it! Even a rockstar idea like the Thomas theorem faces some tough questions. But hey, that's how we learn and grow, right? By asking questions and thinking deeply, we get closer to understanding the complex puzzle that is human life.


Wow, what a ride! From understanding what the Thomas theorem is all about to tracing its historical roots, diving into real-life examples, spotting it in pop culture, and even grappling with its criticisms, we've covered a lot of ground.

You've seen how this nearly 100-year-old idea still holds a lot of weight today, shaping everything from how we act around our friends to the twists and turns in our favorite movies.

But it's not just a one-size-fits-all theory. We've also heard from some pretty smart people who have pointed out where the Thomas theorem might fall short or not tell the whole story. That's the beauty of learning: it opens up doors to even more questions and discoveries.

So, the next time you find yourself believing in something strongly, remember: your belief could very well shape your reality, just like W. I. Thomas and Dorothy Swaine Thomas told us way back in the 1920s.

But also keep in mind that beliefs are just one piece of a much bigger puzzle. We're all part of complex systems, influenced by culture, history, and a bunch of other things that make life interesting and, sometimes, a bit complicated.

Whether you're reading a book, watching a movie, or even scrolling through social media, keep an eye out for the Thomas theorem in action. It's more than just an idea; it's a lens that can help us understand the world a little better. And who knows? The next time you spot it, you might just be inspired to shape your own reality in new and exciting ways.

Reference this article:

Practical Psychology. (2023, September). 49+ Examples of the Thomas Theorem (Description + Critiques). Retrieved from https://practicalpie.com/the-thomas-theorem-examples/.

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