Barnum Effect

The Barnum effect is a cognitive bias that occurs when you believe that generic personality descriptions and statements apply to yourself

Screening, post-screening

Have you ever wondered why horoscopes seem to resonate with you even though they are generic and applicable to almost anyone? Have you ever noticed that horoscopes often contain vague statements that could apply to anyone, yet you still find yourself nodding in agreement? 


This is called the barnum effect.

What is the barnum effect?

The barnum effect is a cognitive bias where individuals believe that vague and general statements about their personality specifically apply to them when in reality, these statements could apply to almost anyone. It’s often referred to as the “Forer effect” after psychologist Bertram R. Forer, who first described it in the 1940s. 

To learn more about the barnum effect, we spoke to Dr Marcia Goddard, a neuroscientist with a specialisation in work floor behaviour.

P.S. You can listen to the full podcast episode below!

How does the barnum effect impact the hiring process?

One of the most common ways barnum effect impacts the hiring process is when employers use personality tests. When it comes to personality tests, the Barnum effect can lead individuals to perceive the results as highly accurate and personalized, even though the statements in the test are often generic and could apply to a wide range of people.

Let’s say a person takes a personality test that includes statements like “You have a strong desire for success” or “You tend to be both social and introverted.” These statements are intentionally vague and general, and most people could relate to them in some way. However, because individuals tend to interpret information in a way that confirms their preconceived notions about themselves, they may perceive these statements as highly accurate and reflective of their unique personality traits, even though they are actually very generic.

P.S. This bias can also trigger self-report bias and social desirability bias.

How does the barnum effect impact the accuracy and reliability of personality test results?

The barnum effect can significantly impact the accuracy and reliability of personality test results. When individuals perceive the statements in a personality test as highly accurate and personalized, they may base their self-perception and behaviour on these results, even though the statements are general and could apply to many people. 

Leading to a distorted view of their own personality, as well as potential misinterpretation of others’ personalities. It can also undermine the validity of the personality test as a reliable tool for assessing an individual’s true personality traits.

How can we prevent personality assessments from suffering from the barnum effect?

There are several strategies that can help prevent the barnum effect from distorting personality assessments. One key approach is to ensure that the statements in the assessment are specific and objective, rather than vague and open to interpretation. This can help reduce the likelihood of individuals perceiving the statements as overly personalized. It’s also important to provide clear instructions to individuals taking the test, emphasizing that the statements are general and may not specifically apply to them. 

Additionally, encouraging individuals to critically evaluate the statements and consider alternative interpretations can help mitigate the impact of the barnum effect on their perception of the results.

What to be mindful of when using personality assessments?

Personality tests can be valuable tools when used appropriately and in conjunction with other assessment methods, but they should not be solely relied upon for making important decisions about individuals’ traits, capabilities, or potential.  It’s about being intentional and targeted in the assessment process, rather than trying to uncover every aspect of a candidate’s personality. 

By aligning assessments with job requirements and being mindful of biases, hiring managers can make more informed decisions and minimize the impact of the barnum Effect.

As suggested by Dr Marcia Goddard:

It’s important that individuals and organizations approach personality tests with a critical mindset and not solely rely on them as the sole determinant of one's personality or capabilities.

Remember that each individual is unique and complex, and no single test can fully capture the complexity of human personality.

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