We have all seen it. You open your Facebook app, scroll for five minutes, and are immediately bombarded with high-drama posts. There is a viral confession about a husband caught cheating, a screenshot of devastating text messages, or an essay from a heartbroken woman exposing her partner’s betrayal.
After seeing these stories day in and day out, it is easy to understand why a sweeping consensus begins to form: “Men are cheaters. Period.”
This emotional reaction is entirely human, but it is scientifically and statistically wrong. When we make this generalization, we drag innocent, loyal partners—like the quiet dads staying home to care for their kids—into a global courtroom where they are judged guilty by association.
So why does our brain play this trick on us? The answer lies in a foundational concept from epidemiology and statistics: Selection Bias.
To draw a valid conclusion about any target population (for example, “all men in relationships”), a researcher must study a sample that truly represents that population.
When you read posts on Facebook, you are not looking at a representative sample. Instead, you are looking at what statisticians call a grab sample (or convenience sample). This is a sample selected by easily employed but highly biased methods—like a “man-on-the-street” poll.
Facebook’s Newsfeed does not randomly select couples to showcase their daily life. Instead, it relies on self-selection bias (or volunteer bias). Think about it: a guy who lovingly buys his girlfriend dinner, washes the dishes, or quietly stays home to look after the kids is not going to go viral. Peaceful, routine loyalty does not generate “engagement.” It is the dramatic, emotionally explosive outliers—the relationship crises—that prompt people to post and share.
Because the stable, happy relationships never “enter the study” (your feed), your sample is systematically skewed toward failure.
There is a brilliant analogy: “Going to a hospital, looking only at the patients in the beds, and screaming: ‘Is there no healthy person left in the world?’” .
In epidemiology, this exact mistake is known as Berkson’s Bias (or the Berksonian Fallacy). Joseph Berkson famously proved that if you conduct a study using only hospitalized patients, you will find false, highly distorted associations between diseases because hospitalized individuals are systematically selected because they are sick.
Social media is the digital equivalent of a hospital ward for relationships. It is a repository where broken or “sick” relationships are brought for public diagnosis and support . If you restrict your worldview to the hospital beds of Facebook, concluding that “all men cheat” is identical to looking at a row of hospital beds and concluding that “all humanity is terminally ill.”