Belief Bias
We judge an argument's strength by the believability of its conclusion, not by its logical validity.
Belief bias is the tendency to evaluate the logical strength of an argument based on the believability of its conclusion rather than the actual validity of the argument. People accept invalid arguments if the conclusion is believable and reject valid arguments if the conclusion seems unbelievable. This fundamentally compromises logical reasoning in everyday contexts.
What it looks like in the wild.
- Everyday life Climate Argument Acceptance People accept poor-quality arguments supporting their existing climate position and reject logically valid arguments supporting the other position.
- Everyday life Rejecting Valid Logic When shown the valid syllogism 'All mammals can walk; whales are mammals; therefore whales can walk,' people reject it because the conclusion conflicts with their knowledge, instead of recognizing the flawed premise.
Recognising a definition is not the same skill as spotting it.
Two scenarios from the app, with distractors drawn from the same family of biases — which is what makes them hard.
Lisa agrees with her boss's plan because she admires her boss, even though she hasn't considered the plan's feasibility.
Maria rejects a colleague's proposal to improve team productivity because she doesn't like the colleague, even though the proposal has clear logical steps.
Biases rarely arrive alone.
Understand more. Assume less.
188 biases, 18,869 scenarios, and a record of how you actually decide.
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