Confirmation Bias

We all like to be right. Confirmation bias is our mind’s way of cheating to feel right more often. Psychologically, once we form an opinion, we subconsciously filter information, noticing bits that support our view and ignoring those that contradict it.

In software, a typical scenario is debugging. A developer convinced that module A caused a production issue will comb through module A’s code intensively. If module B (assumed to be fine) is also throwing errors, they might not even look there, missing the real cause. Awareness of this bias leads to asking “What am I missing? Maybe there is another explanation?” and encouraging environments where beliefs are constructively questioned.

• When reviewing code or debugging, notice if you're only looking for evidence that supports your initial hunch.
• Challenge yourself when actively thinking about problems. If you have an opinion about an issue, try to ask, 'What would I expect to see if I'm wrong?' In this, we can counteract our natural bias only to confirm.
• Regarding team decision-making (for example, tech stacks and/or design decisions), seek input from people with differing opinions. Bias confirmation can be overcome by looking into alternative solutions. For example, if the whole team 'feels' that technology X is the superior choice, assign someone to look into the opposing view on technology X.
• Base decision-making on objective criteria (facts, not opinions). Automated tests, performance criteria, and experimentation (A/B tests) can provide truths regardless of human bias.