Mere-measurement effect
Also known as: Question-behavior effect
Just asking people about a behavior makes them more likely to do it.
What it means
The finding that merely asking people to predict or state their intentions about a behavior increases the likelihood they will perform it, without any persuasion or incentive. Posing the question makes the behavior and one's attitude toward it cognitively accessible, and committing to a stated intention engages consistency pressures that carry into action. The effect is modest but reliable and has been used as a low-cost nudge for voting, purchasing, and health behaviors. It matters because it shows that the act of surveying is not neutral — measurement itself can change what it measures.
Examples
Asking people 'Do you intend to vote?' raises their turnout relative to those not asked.
A survey asking car owners when they next plan to service their vehicle nudges them to book sooner — the question puts the task in mind and turns a vague plan into a stated one.
A dentist's reminder that asks 'will you come to your check-up on Tuesday?' rather than simply stating the date lifts attendance, because answering out loud is a small promise to keep.
First described in Morwitz, Johnson & Schmittlein (1993); Sherman (1980).