Confirmation Bias

Suppose you go to see your therapist and he suspects that you’re suffering from depression. He asks you the following questions: (1) have you been feeling lethargic lately? (2) have you noticed feeling more sad and emotional than usual? (3) perhaps an increase in irritability? (4) having difficulties with concentration? (4) decreased appetite? (5) sleep disruption? (6) no longer getting the same pleasure out of your activities? (7) maybe you’re feeling less motivated than usual? (8) less interested in spending time with your friends? These seem like reasonable questions to determine whether you are, in fact, depressed.

Unfortunately, while these seem like reasonable questions they are examples of confirmation bias. The questions are actually poor because the therapist is simply looking for evidence to confirm their suspicion and chances are he will find it. This is a sloppy, irresponsible, and intellectually lazy way of making a diagnosis. The problem, of course, is that not only therapists make this kind of mistake. We all tend to find what we look for. As Abraham Maslow once said, “If you only have a hammer, you tend to see every problem as a nail.”

The solution to this thinking error is to actively seek disconfirmatory evidence. It’s easy to be “right” but this often leads to shallow, incorrect judgments of others based on limited information. It’s more balanced and fair to others to try to prove yourself wrong. Using the earlier depression example, a better line of inquiry would be to assume that the person is happy and well-adjusted until proven otherwise. Asking about how happy the person has been and what brings them joy are good starts. If we have an acquaintance who we think is a jerk it would be very easy to cast all of their behaviors through that lens. A smile could be seen as a sign of condescension. A compliment could be seen as manipulation. If they hold the door for you it just proves that they’re sexist. If would be kinder and more intellectually honest to look for reasons why they’re nice. If you can’t find any niceness to prove your theory wrong and it still stands up then you can have more legitimate confidence in your initial judgment.