Congruence bias
The tendency to test an idea only by checking whether its predicted result happens, without testing other explanations that could produce the same result. It is a close cousin of confirmation bias that shows up in how we test things.
In everyday life
A manager thinks a sales dip was caused by a weak ad, so she keeps trying new ads and never checks whether a recent price increase is to blame.
Believing your houseplant is drooping from thirst, you water it more and more to see if it perks up, and never try moving it out of the hot, sunny window.
Why your mind does this
Holding steady beliefs lets us act without rethinking everything each time. Favoring information that fits what we already know is fast, protects our sense of being right, and keeps our picture of the world stable and coherent.
Its family, in 30 seconds: Confirms beliefs
How to spot it
Ask yourself which other explanations could produce the same result, and whether your test could tell them apart.
How to counter it
For every idea you test, name at least one rival explanation and design a check that could rule it in or out.
Habits that catch it
- Argue the other side
Before you commit, write the strongest case against your view. If you can't, you don't know the question well enough yet.