While it seems harmless, the Barnum effect becomes dangerous when it interferes with our decision-making. What happens when we take the preachings of a newsstand astrology book as accurate predictions about our future? Believing that general information applies directly to ourselves prevents us from being able to logically analyze our options and choose the best outcome possible. For example, what if you refused to date someone because their zodiac sign was “not compatible” with your own? Or what if you refused to leave the house because your horoscope foresaw tragedy in your impending future? If we trust these vague predictions too much, they can change the course of our lives by steering us clear of decisions we would otherwise make.

Perceptions of health advice

Whether it’s horoscopes in newspapers, messages in fortune cookies, or palm readings at festivals, we encounter generic statements that trigger the Barnum effect daily. But this psychological phenomenon can affect us beyond these casual (and largely harmless) encounters. For example, when someone receives generalized health advice from an alternative medicine practitioner, they may interpret the information as personally relevant, even if there is no scientific evidence to support their diagnosis or proposed treatment.

One 1994 study explored this issue more closely, finding that participants rated bogus feedback about their health as highly accurate, even though it was incredibly vague and could apply to anyone.¹¹ With this in mind, the researchers concluded that the Barnum effect could, in part, explain why some people advocate for alternative treatments that have no scientific basis. If generalized health information resonates with someone’s beliefs about their own symptoms or experiences, they may be more likely to accept that it’s true.

Self-diagnosis and social media

The Barnum effect might also play a role in the growing trend of young people self-diagnosing disorders like ADHD, OCD, autism, anxiety, and depression. Some therapists suggest that social media platforms like TikTok are to blame for this emerging issue.¹² After seeing social media content about these disorders, some people feel that the symptoms discussed accurately describe their own experiences. For instance, someone in a video talking about Autism Spectrum Disorder might make vague statements about feeling awkward in public, having trouble making eye contact, or not understanding sarcasm. People who relate to these videos might feel that these symptoms are unique to them and, therefore, indicative of autism. But in reality, some of these things are just normal human experiences that everyone encounters to some extent.¹¹ 

Of course, increasing awareness surrounding these disorders is not a bad thing; it’s dispelling stigma and encouraging people to seek help. But there is a downside. For instance, experts caution that self-diagnosing ADHD based on vague or misleading information—which often positions people’s common quirks as ADHD symptoms—can undermine the struggle that people with the disorder have to face every day.¹³ Not only that, but these videos often encourage people who suspect they have ADHD to pursue a professional diagnosis, even if the traits that resonate with them are not significantly impacting their quality of life. This rise in self-diagnoses and subsequent visits to the therapist is straining already stretched waiting lists, making it harder for people who genuinely need help to access care.¹⁴

Beyond impacting our individual experiences, the Barnum effect can affect larger systems and society overall. From shaping how employees process feedback to influencing how people internalize stereotypes, this bias has a far-reaching impact on our collective behaviors.

Employee feedback

Within an organization, the Barnum effect may determine how willing employees are to accept or reject feedback. As explained below, we are more likely to believe that positive generalized statements apply to us. This means that when a manager applauds their team for their good work, employees may be inclined to proudly accept the compliment—even if their boss is not referring specifically to them. 

Conversely, we are resistant to negative generalized statements and often refuse to see them as applying to us. Due to this tendency, employees may find it difficult to incorporate criticism when a manager offers constructive feedback to their team, choosing to believe it applies to everyone else but not to themselves. 

With this in mind, higher-ups may want to prioritize providing individual feedback to each employee to guarantee they will accurately relate the feedback back to themselves, rather than amplifying their achievements or brushing off their shortcomings. 

Stereotypes and self-fulfilling prophecies

Zooming out to society as a whole, the Barnum effect could also perpetuate stereotypes about certain groups. How? Consider the self-fulfilling prophecy, where people’s beliefs about themselves or a situation subtly influence how they behave, which in turn causes their expectations to become reality. If you accept vague descriptions of a group you belong to as accurate depictions of your own traits or abilities, you might inadvertently reinforce those social expectations. For example, if a woman identifies with the stereotype that “women are naturally passive and quiet,” she might unconsciously align her behavior with this assumption.

This tendency to internalize stereotypes can be seen in all types of groups, including adult children of alcoholics (ACOA). Many ACOAs identify with a laundry list of similar characteristics like impulsivity, overreaction to change, and approval-seeking tendencies—these traits are frequently highlighted in support groups. Research suggests that the popularity of applying broad personality characteristics to this group is likely partly due to the Barnum effect. 

One study tested this theory by giving people bogus personality profiles and then asking them how well these profiles described themselves, people in general, or children of alcoholics.¹⁵ Interestingly, both ACOAs and non-ACOAs found all personality profiles to be highly descriptive of themselves, regardless of the traits described. They also felt that the profiles described them better than people in general or children of alcoholics, suggesting that the Barnum effect may be partially responsible for the widespread acceptance of such traits. 

Regardless of whether or not groups actually share certain traits, the tendency to accept these traits as definitive can shape how people view themselves and others, reinforcing limiting beliefs and perpetuating societal stereotypes.

The Barnum effect is a very common phenomenon resulting from our natural tendency to attach personal meaning to general statements.² It’s rooted in another cognitive bias known as subjective validation (sometimes referred to as the validation effect). Subjective validation is when we consider information to be correct if it has personal significance because we subconsciously identify a relationship between two unrelated events.³ Like subjective validation, the Barnum effect results from taking a vague statement and finding meaning specific to ourselves by connecting completely separate entities.

Interestingly enough, the Barnum effect seems to happen most often with positive statements. For example, we are more likely to think our horoscope is accurate if it contains positive information. On the other hand, this means that we are typically more skeptical of critical statements, and are less likely to think they pertain to us.⁴ So if our horoscope points out any personality flaws about our zodiac sign, we might brush it off as being nonsense. 

This trade-off makes perfect sense. After all, people like to be complimented, and will more likely accept positive feedback about themselves as accurate, even if it is general and vague. We can better describe this phenomenon with the Pollyanna Principle, also commonly referred to as the positivity bias, which occurs when an individual assumes better accuracy of descriptive statements when they are positive.⁵ Subconsciously, individuals are biased to eagerly accept praise—and in turn, swiftly reject criticism. After all, who would want to believe that negative comments refer directly to themselves when it is so much easier to dismiss them?

Another bias that often co-occurs with the Barnum effect is confirmation bias, which describes our tendency to interpret new information in a way that confirms our existing beliefs. Confirmation bias makes us even more likely to accept broad statements about ourselves when they align with how we already see ourselves. If you believe that you’re a hard worker, you’re more likely to internalize a horoscope that praises your work ethic. And because of the confirmation bias, you might gloss over other information in the horoscope that doesn’t fit your existing self-image. This bias amplifies the Barnum effect by making us focus on the vague statements that confirm what we already believe while overlooking information that contradicts how we see ourselves.

By being aware of this effect, we can be attentive to any potential scenarios where we could be easily influenced and think twice before applying vague information to ourselves. This can help us become less vulnerable to manipulation, not just by writers of horoscope descriptions but also by clever marketers who wield the Barnum effect to make us feel special or unique. For example, a marketing message might try to capitalize off the Barnum effect by saying something like “You’re a leader, not a follower, so you need a solution that matches your unique personality” or “Your life is chaotic, but this product will finally bring you the peace you deserve.” These statements could apply to anyone, but they make products and services seem uniquely tailored to you.¹⁶

Recognizing the Barnum effect in everyday life can help us all become more independent thinkers. Not only can this help us avoid paying for products and services we don’t really need, but it also gives us the power to present ourselves the way we want. When we avoid automatically accepting generalized information that’s directed at us, we gain greater control over our own self-image. For example, those who are skeptical of horoscopes and wary of psychic advice tend not to let these predictions dictate their lives and choose to follow their own paths instead.

As in many situations, awareness and skepticism are crucial to avoiding certain cognitive tricks. Even though you may enjoy checking your horoscope for fun, knowing about the Barnum effect can prevent you from believing it directly applies to you. Rather, you can move forward with your life by making informed decisions.

Though merely being aware of cognitive effects such as the Barnum effect cannot ensure that we will not fall privy to its illusion, awareness does provide a starting point. That way, both individuals and organizations can learn how to identify Barnum statements and how they are subconsciously affected by this bias.

Recognize vague statements

Before you can avoid the Barnum effect, you must be able to recognize it. Whether you’re taking a personality test or reading a horoscope, notice vague descriptions and generalized statements that could resonate with anyone. Keep in mind that people are less likely to believe that negative statements apply to them, so these are usually offset by something positive.¹ Consider this common example: “While you have some personality weaknesses, you are generally able to compensate for them.” Think about statements like these carefully. Can you think of a single person this doesn’t apply to? 

Verify information

When confronted with information that seems like it might apply to you, seek evidence—don’t accept broad statements without satisfactory proof. While you unfortunately can’t debate the person who wrote your horoscope, you can do your own research and seek second opinions. If you come across a video where someone is sharing “signs that you might have ADHD,” do some research into ADHD symptoms yourself—prioritizing reputable sources like medical websites—and consult a medical professional to determine if your symptoms could actually be indicative of ADHD or if they’re more likely part of the normal human experience. 

Don’t fall for cold reading

It’s also important to be aware of “cold reading” techniques used by mentalists and psychists, which allow them to gain a lot of information about you just by analyzing the subtle ways you respond to high-probability guesses (vague statements that are likely to apply to you).¹⁷ Cold readers are masters at picking up on small changes in facial expressions and body language that indicate they’re on the right track, and their success depends entirely on the Barnum effect convincing you that they’re talking about you specifically. While there’s no harm in talking to fortune tellers or reading your horoscope for a bit of fun, approaching this information with a healthy degree of skepticism is important for making decisions that are ultimately grounded in reality.

The Barnum effect is named after the famous 19th-century American showman P.T. Barnum, whose life story inspired the film The Greatest Showman. Barnum famously said that “a sucker is born every minute.” His statement refers to how people’s gullible nature prompts them to believe what they are told about themselves, explicitly referring to the elaborate hoaxes in the circus industry that Barnum dominated.⁶

The Barnum effect was first officially investigated by American psychologist Professor Bertram R. Forer, explaining why the bias is also commonly referred to as the Forer effect. He conducted what is thought to be the first experiment testing the cognitive effect in 1948, during which he provided his psychology students with personality surveys. He informed the class that each survey would be analyzed and then returned to the students with personalized feedback on their scores. Secretly, the professor instead gave the students the same general, unspecific feedback, regardless of their personality test results.

The feedback included general phrases such as, “You have a great need for people to like and admire you,” or, “You have a tendency to be critical of yourself.” After receiving the initial feedback, the students evaluated its quality, giving it a score ranging from zero (not accurate at all) to five (incredibly accurate). The experiment was a success at proving the Barnum effect since the average student rating was 4.26. This means that most of the class viewed their feedback as impressively accurate to themselves, even though the comments provided were the same general statements for all of the students.⁷ Bertram Forer originally referred to this phenomenon as the "fallacy of personal validation.”

Later on, the name “Barnum effect” was coined in 1956 by American clinical psychologist Paul Meehl. He adopted this term after expressing his frustration towards other psychologists who were persistently making general statements about their patients.⁷ Meehl saw this as negligent practice, and advocated for individuation of diagnoses instead.

The Barnum effect can impact how larger companies interact and form relationships with customers. As commonly seen in marketing campaigns, this cognitive bias exaggerates the impression of a uniquely personalized experience. When executed correctly, the Barnum effect can encourage customer buy-in and strengthen brand loyalty. On the other hand, this bias allows companies to effectively deceive consumers into feeling as though they are personally interacting with the brand—when in reality, that brand was intentionally designed to appeal to a broad audience. As companies develop more sophisticated tactics to target their customers, we should expect more examples of the Barnum effect to be integrated into our goods and services.

Although AI software such as ChatGPT often generates generic results, the Barnum effect may prompt us to believe that their answers are tailored specifically to our questions. Users may perceive the incorporation of technical terms as personalized instead of a standard output of the machine learning model. This misinterpretation enhances the Barnum effect by tempting us to view ChatGPT as our private expert, rather than an automated response.

One of the oldest and most common examples of the Barnum effect lies in astrology. This practice can be traced back nearly 2,000 years ago to ancient civilizations when horoscopes were first used for their predictive powers.⁸ Since then, professionals such as magicians and palm readers have succeeded in convincing many people of their foreseeing abilities.

By using the Barnum effect to describe common personality traits in ways that seem unique to a singular individual, astrology has garnered incredible popularity all around the world. Horoscopes provide “readings” or predictions for twelve different types of profiles called zodiac signs, which split up the sun’s path into equal sectors. The zodiac signs include Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces. Everyone falls with one of these signs depending on the time and location of their birthday within a sector. Horoscopes can vary in content but usually provide descriptions of a sign’s typical personality traits, while also offering future predictions that range in topics such as career, love life, family, and personal development.⁹

Susan Miller, the famous astrologer and horoscope writer, publishes lengthy horoscopes for each zodiac sign on a monthly basis. Although historically Miller has wrongly predicted many famous world events, she still is one of the most renowned horoscope writers. Her website is the most heavily trafficked astrological online resource in the world. Miller’s success is rooted in her talent for writing lengthy and uplifting vague passages for her readers. Using the Barnum effect, Miller forges a sense of connection between her readers and the text convincing thousands of people around the world that her predictions are relevant to themselves in particular.¹⁰

Digital products provide a modern-day example of how the Barnum effect can engage customers and provide them with enhanced user experiences. Customers commonly favor digital providers such as Netflix and Spotify because of the personalized features incorporated in their products’ design, such as recommended movies and customized music playlists. It is as if the content was handpicked “just for them.”

Though digital companies give users a false sense that the applications cater to each client’s tastes, in reality, they only offer slightly personalized services. Yes, it may be true that machine learning somewhat aids in developing these general recommendations. However, the Barnum effect amplifies the perceived personalization of these products to guarantee customer satisfaction. 

Technology is currently not advanced enough to give everyday users the endless amount of customizable content we demand from our products. Hence, the Barnum effect provides a sense of curation without technology companies having to fully tailor to each customer. The perception that these services are completely customized, in turn, makes a customer feel valued, and more likely to continue streaming movies and music from these companies.

What it is

The Barnum effect is a cognitive bias that occurs when individuals believe that generic personality descriptions and statements apply specifically to themselves when in reality, they could apply to almost everyone.

Why it happens

The Barnum effect occurs due to our brains’ inherent tendency to attach personal meaning to general statements. In particular, positive comments are naturally more accepted by the average person as relevant to themselves, while critical statements are deemed less relevant. 

Example #1 – Horoscopes

Horoscopes serve as a classic example of the power of the Barnum effect. Astrology provides 12 different zodiac signs based on one’s location and time of birth, categorizing personality traits and providing future predictions regarding career, love life, family, and personal development. The Barnum effect helps readers make connections between the vague descriptions and their own personal lives.

Example #2 – How Netflix and Spotify pretend to know us

Personalized digital products provide a modern-day example of ways the Barnum effect is used to engage stakeholders and create better products and services for customers. Netflix’s “Just for You” movie lists and Spotify’s “Discover Weekly” playlist give software users a sense of customization and personalization.

How to avoid it

Skepticism is vital in recognizing the Barnum effect in your everyday life. Though merely being aware of this cognitive effect does not ensure that one will not fall privy to its illusion, awareness does provide a starting point to ensure that both individuals and organizations avoid using the Barnum statements maliciously or are affected by the bias subconsciously.

The Science Behind the Barnum Effect

This article explores the history of horoscopes and our fascination with believing their predictions. The author notes how horoscopes rely heavily on the Barnum effect, by providing vague personality descriptors that individuals believe apply to themselves. The article later touches on how the Barnum effect can be applied to marketing and explores how businesses can leverage it to better engage with their customers.

The Self-Fulfilling Prophecy of Internet Outrage

We briefly discussed how beliefs about ourselves can become a self-fulfilling prophecy reinforcing those beliefs. In the same way, our beliefs about others—often shaped by social media—can perpetuate hostility and feed division. This article discusses how social media causes us to overestimate polarization and why this often becomes a self-fulfilling prophecy, ultimately dividing us.