Analysing your IQ
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AKA: "Big Cause for Big Effect"
Assuming that big events must have big, complex causes.
Proportionality Bias is one of the most common cognitive errors—and one of the hardest to spot in yourself. This page explains what it is, why your brain does it, and how to mitigate it.
You can't believe a lone gunman changed history, or that a small mutation caused a pandemic. You seek grand explanations.
High-stakes domains (medicine, law, finance) have developed entire systems to counteract Proportionality Bias. If professionals need safeguards, so do you.
This error is driven by Pattern-matching brains expect scale matching: important effects should have proportionally important causes..
Evolution optimized for speed and safety, not truth. Proportionality Bias is a byproduct of heuristics that once had adaptive value.
In investing: Proportionality Bias leads to holding losing positions too long or selling winners too early.
In relationships: This bias causes people to interpret ambiguous signals in ways that confirm existing beliefs about partners.
In work: Proportionality Bias makes it harder to update strategies when market conditions change.
In health: People ignore symptoms that contradict their self-image as "healthy" or "young."
Experiments on Proportionality Bias often use controlled conditions that make the bias obvious to observers—yet participants still fall for it. This demonstrates how powerful the effect is.
Accept that small causes can have large effects, especially in complex systems with feedback loops.
Seek disconfirming evidence: Actively look for data that challenges your current belief.
Use decision journals: Write down predictions before outcomes are known, then review accuracy.
Consult diverse perspectives: People with different backgrounds spot different biases.
Implement decision rules: Pre-commit to criteria before emotionally charged situations arise.
Time-box decisions: Revisit important conclusions after a cooling-off period.
Some brains are more susceptible to this than others. Test your Intelligence to find out.
Assuming that big events must have big, complex causes.
The alternate name "Big Cause for Big Effect" captures the intuitive essence of the bias. Proportionality Bias is the formal psychological term, while "Big Cause for Big Effect" describes what it feels like in practice.
Accept that small causes can have large effects, especially in complex systems with feedback loops.
The underlying mechanism is pattern-matching brains expect scale matching: important effects should have proportionally important causes.. Human brains evolved heuristics for speed and survival, not accuracy in modern contexts.
Yes. Intelligence doesn't provide immunity—sometimes it makes the bias worse because smart people are better at rationalizing. Awareness and structured decision processes are more protective than raw IQ.
You can't believe a lone gunman changed history, or that a small mutation caused a pandemic. You seek grand explanations.