By Philip Copitch, Ph.D.
Dear Dr. Phil,
Great Question Gerald,
People do this all the time and usually it has no ill effect. Let’s say you phone a friend and he doesn’t pick up. You probably assume he’s not home and decide to call him again later. In this story, you chose to assume that your first and only hypothesis is correct (friend not home) but, maybe you dialed the number incorrectly, or maybe he is eating dinner.
An example:In drug rehab research it was a common belief that high school students that use marijuana are more likely to move onto harder drugs like heroin and methamphetamine. This mistaken idea came from surveying drug addicts and asking them what their first drug was. Many reported that they started with pot. On the surface this makes sense. But the survey question was flawed. It did not look at other things that could have been the gateway to hard drugs. Just because hard drug users reported pot in their past, the researchers stopped looking for other causes (Congruence Bias). The assumption was, pot came first, and pot was a nasty hippie young person drug, thus it must have caused the hard drug use. It was statistically sound, a large percent of heroin users reported it. But it was incorrect.
So, to avoid congruence bias, I highly recommend asking ourselves, "How can I do/look/think about this differently?"
Wason, P. C. (1960). On the failure to eliminate hypotheses in a conceptual task. Quarterly Journal of Experimental Psychology, 12, 129-140.
Jonas, E., Schulz-Hardt, S., Frey, D., & Thelen, N. (2001). Confirmation bias in sequential information search after preliminary decisions: An expansion of dissonance theoretical research on selective exposure to information. Journal of Personality and Social Psychology, 80, 557-571.