People seem to stubbornly cling to their preexisting beliefs, even when provided evidence to the contrary. In psychology, researchers have a name for this stubbornness — confirmation bias. It’s one of the most common of biases humans hold in their mind, called cognitive biases.

Confirmation bias is the tendency for a person to interpret or remember information in a manner that simply confirms their existing beliefs. It is one of the strongest and most insidious human biases in psychology, because most people are unaware they are doing it. It is the invisible voice inside our heads that always agrees with what we say, no matter the facts.

Confirmation bias, also referred to as myside bias, exists in our everyday decisions. We primarily rely on evidence that supports our opinions and beliefs, and disregard anything contrary to those beliefs. This bias can emerge in a number of different ways:

How we search for & find information

How a person searches for information can significantly impact what they find. Imagine a scientist who has a hypothesis they want to test. Most scientists don’t come at a hypothesis out of the blue. It’s usually based upon their existing beliefs and other data they’ve researched. So by asking a new research question in a specific way, they can subtly bias their search for information, finding exactly the results they thought they would find.

Lawyers are adept at helping people draw biased conclusions by asking questions in a leading manner. “So you can’t prove you were asleep at 3 am when the victim was murdered?”

Social media “filter bubbles” make it very difficult to undo confirmation bias.

In today’s world, “filter bubbles” — when social media websites tailor their feeds to show you exactly what it is they think you want to see — make it very difficult to undo confirmation bias. If you believe in UFOs, YouTube or Facebook will be happy to confirm the existence of UFOs in a never-ending stream of new videos and posts providing confirming evidence of them.

How we interpret information

Even when given the exact same evidence, people who hold conflicting views on an issue may arrive at opposite conclusions. For instance, when shown data that gun control laws help reduce the murder rate in a state, a gun control advocate might say, “See, the data support more gun control laws.” A proponent of fewer gun control laws might look at the same data and say, “It’s simply a correlation, and all good scientists know that correlations don’t prove causal relationships.”

Not only can we look at the same information and reach two opposite conclusions, we will often require more stringent standards for evidence that competes with our existing beliefs. In the above example, the gun proponent might further suggest, “Show me the longitudinal, controlled study that clearly demonstrates this relationship over time, in multiple geographical regions, across all genders and race, and in both urban and non-urban settings.”

How we remember information

Some jokingly refer to this bias as selective recall, when a person only remembers the information that confirms their existing beliefs. Couples often bicker remembering relationship incidents differently.

“You were rude to my father when you spoke to him last.”

“I don’t remember it that way, I just thought I was answering his questions and didn’t have much else to say.”

It appears that information matching our previous expectations is more strongly encoded than information that is contradictory to those expectations. Memory is also dependent upon emotional state, so memories made during an emotionally charged time may be better encoded than others. In recall, such emotional memories may override the facts of the situation.

Now that you know about confirmation bias, the obvious question is how can you prevent it from influencing your every decision? The short answer is that there is no easy way to do this. That’s because this bias — like all cognitive biases — is typically unconscious. Most people are unaware they’re engaging in confirmation bias.

What you can do is learn to challenge yourself more in your everyday preconceptions — especially those areas where you feel very strongly about. The more strongly we feel about an issue, the more likely confirmation bias may be at work. Seek out competing explanations and alternative viewpoints, and try and read them with an open mind.

While it may not do away with confirmation bias in your life, it may help make you more aware of when it may be functioning. And that could go a long ways in helping you better understand your own self.