Confirmation Bias

Confirmation bias refers to our tendency to seek and favour information that confirms our pre-existing ideas, and to interpret ambiguous information as supportive of our beliefs. That is, we pay attention to and believe information that confirms what we already think, while ignoring contradictory information. So for example, if I believe that the city where I live has the best restaurants in the world, I'll notice and remember every delicious meal I eat in my city--ignoring any poor customer service or bad food experiences, and forgetting about delicacies consumed in other cities.

How does confirmation bias manifest in clinical psychology practice?

We all have automatic thoughts and core beliefs about ourselves, others, and the world. Some of our problematic thoughts and beliefs aren't quite accurate and, reinforced by confirmation bias, they can be quite resistant to change. Consider one of my patients--an undergraduate student who was depressed after a longterm relationship ended. She was very lonely after the break-up, and frequently had the thought that everyone in the world but her was in a relationship. This recurring thought meant that every time she attended a social event, she was hyper-aware of couples and failed to notice people who had arrived alone or with friends. In our sessions, my patient repeatedly compared herself to her two best friends, both of whom were in relationships, ignoring that her sister and her roommate were both single.

As her depression deepened, my patient's recurrent thought was reinforced by confirmation bias and consolidated into a biased belief: if she was the only single person in her peer group, she must be unlovable. The belief that she was unlovable was in turn reinforced by confirmation bias: when her friends organized a huge surprise birthday celebration, she reported they were just looking for an excuse to party. When her lab partner asked her out, she assumed it was only because he wanted to copy her notes.  Her confirmation bias prevented her from taking in any information that contradicted her belief that she was unlovable, maintaining both the belief and the depression. 

You don't have to be clinically depressed to experience the effects of confirmation bias. Think about the last time you woke up in a bad mood. You probably paid a lot of attention to the guy whose massive backpack took up an extra seat on the subway, or to the fact that the elevator at work was out of service again. You probably failed to notice the gorgeous weather, or the delicious lunch your loving partner packed you. Why? Because these things didn't fit in with your preconceived idea that day that the world was a lousy place.  

How can we challenge confirmation bias?

The trick is to realize when we're in the grip of confirmation bias, to identify the bias, and to be willing to test it. Example: I have a patient who has a high-powered job and young kids, but her life is more difficult than it needs to be because she believes that fundamentally, other people are incompetent. Not only does this belief create interpersonal conflict, but it means that she can never delegate responsibility for any task or chore to her colleagues, her husband, or her kids because they're liable to do it wrong.

After a bit of psychoeducation about CBT, and some work on cognitive distortions, she agreed to test her belief. Armed with the scientific hypothesis "Others are incompetent," she set out to complete the following assignment: for one week, record evidence that supported or contradicted her belief. Evidence that supported the belief included "My husband put my daughter's diaper on backwards" and "The construction on my street that was supposed to be completed two months ago still isn't done." Contradictory evidence included "The tech support guy at work fixed my printer," "The airline actually served me the gluten-free meal I ordered," and "My son did his homework while I was away."

Faced with clear evidence that others are not always incompetent, my patient was forced to reconsider her belief. She modified "Others are incompetent" to "Other people can be incompetent sometimes, but often get it right." My patient's new faith in her husband, children, and colleagues smoothed relationships and allowed her to delegate tasks, leaving her a bit of time to relax.

Challenging confirmation bias is tricky and requires an open mind. If there's a thought or belief that's making you depressed or anxious ("I never do anything right"), creating relationship problems  ("No one could ever really love me"), or generating stress ("Asking for help implies weakness"), try looking around for information you might be ignoring, and for possible reinterpretations of the information you've been using to justify your belief! 

NB: Sneaky confirmation bias occurs on sites like Facebook that use algorithms to feed us information. Example: If in following the US election, you clicked on and "liked" all your Obama-supporting friends' statuses and ignored all your Romney-supporting friends' posts, your Facebook news feed narrowed, showing you more news from your Democrat friends and fewer posts from your Republican friends. Through the Obama supporters' posted statuses and articles, you learned more about why the Democrats were the better party, and received little information that challenged this perspective--maintaining and strengthening your bias.