State your estimate before encountering vivid case information

Lock in a prior probability estimate before reading a compelling story or meeting a specific candidate.

Why it works

Vivid case information is the primary trigger for attribute substitution: a compelling story or memorable prototype provides a ready-made easy attribute that replaces deliberate probability reasoning. Pre-committing to a probability estimate before encountering the vivid information anchors the deliberate calculation and makes the subsequent vividness effect visible as a deviation from the prior, rather than as a self-evident update.

How to do it

1. Before reading an application, pitch, or case study, write your base-rate probability estimate.
2. After reading, write your updated estimate.
3. If the update is large, ask explicitly: "What specifically changed my probability — new facts, or affect and representativeness?"

Evidence

Pre-commitment to a prior probability is a standard debiasing technique recommended in decision-quality frameworks. It is consistent with anchoring research showing that established anchors resist vivid informational updates. (mechanistic)

A pre-committed estimate can itself become an anchor that under-weights genuinely informative case evidence. The goal is balanced updating, not complete resistance to new information.

Common mistake

Pre-committing to a number and then treating all deviation from it as bias — vivid information sometimes is genuinely diagnostic. The tool is to make the deviation visible, not to prevent updating.