We all like to believe we’re careful thinkers who gather and evaluate facts before making a decision. Unfortunately, we’re not.

We tend to seek information we find favourable and which supports what we already think. In short, we reach a conclusion first, then test it against evidence, rather than gather evidence first and evaluate it to make a conclusion.

This is called confirmation bias, which is a type of cognitive bias (like the bandwagon effect, or the availability heuristic) in which we tend to notice or search out information that confirms what we already believe or would like to believe. To avoid the discomfort of finding information that doesn’t support our views or ideas, we will discount or disregard evidence that’s contrary to our beliefs or preferences.

This plays out in similar ways across a range of contexts. In the sciences, theories are developed through falsifying and supporting evidence. Researchers need to recognise their own potential confirmation biases that come with holding a strong view or belief in the face of other evidence.

Confirmation bias plays out both in a range of research disciplines and our everyday decision making. When we research brands or products we tend to seek out information that reinforces our tastes and preferences. For instance, being drawn to reviews favouring brands we already like.

Confirmation bias is also at play in more significant life decisions like superannuation and other investment choices. Often, the greater the significance of a decision, the greater the likelihood that confirmation bias will be in play. If we don’t want to be left behind when we hear friends or colleagues talking about how well an investment is doing, our research will be strongly influenced by the story of our friend’s success. In doing so, we may filter out information that raises red flags and instead focus on the information validating the investment.

Our technology comes full with confirmation bias. Social media news feeds and online sources are ready made filters of information from people who think like us. Paradoxically, the tools and technologies that make information so accessible heighten the likelihood of us being drawn into information loops which reinforce what we think we know. As Warren Buffett famously remarked, “What the human being is best at doing is interpreting all new information so that their prior conclusions remain intact”.

Like several other biases, confirmation biases are an example of ‘motivated reasoning’. Motivated reasoning describes how our judgments are consciously and unconsciously influenced by what we think we know. This shapes how we think about our health, our relationships, how we decide how to vote and what we consider fair or ethical.