Laws of Behaviour

Mental models for product design

023Effect

Hawthorne Effect

People modify their behaviour under observation.

Why it matters

The Hawthorne effect refers to a tendency in some individuals to alter their behaviour in response to their awareness of being observed.

This is why it's so often difficult to get 'true' UX feedback. The act of watching a new user (or asking them about their experience), may alter what they do.

i.e., they may spend longer reading an onboarding tooltip, if they know that they're being watched, as skipping it would feel rude or lazy.

As an example, a study found that medical staff were 55% more likely to wash their hands, if they knew that they were being monitored.

If the Hawthorne Effect can be that influential in a situation where the benefits are so unambiguous, and from a field of professionals, you can only imagine how inaccurate user testing can be.

Feature usage:

• When users know that they're being actively monitored, they will exaggerate or modify their behaviour. • e.g., if you knew you were being watched, you might bother to read a service's onboarding more carefully—because you might guess that you'd be tested on what you read later.

What to inspect

  • Check whether the experience reflects this: When users know that they're being actively monitored, they will exaggerate or modify their behaviour.
  • Check whether the experience reflects this: This is why it's so often difficult to get 'true' UX feedback.
  • Check whether the experience reflects this: The act of watching a new user (or asking them about their experience), may alter what they do.

Common anti-patterns

  • Assuming users consciously notice every place where "People modify their behaviour under observation" could apply.
  • Dense copy and parallel actions that increase mental effort unrelated to the user’s goal.
  • Ignoring downstream effects on feature usage when shipping this pattern.

Critique prompts

  • When users know that they're being actively monitored, they will exaggerate or modify their behaviour.
  • This is why it's so often difficult to get 'true' UX feedback.
  • The act of watching a new user (or asking them about their experience), may alter what they do.
  • Where on this screen would "Hawthorne Effect" show up as friction or misunderstanding?
  • What would a first-time user misunderstand here in under five seconds?

Related laws