Schiphol etched a fly into urinals and cut cleaning costs

During Schiphol's 1991 terminal renovation, the team led by manager Aad Kieboom faced the eternal washroom problem: spillage that made cleaning a major recurring cost, immune to signage and appeals.

Cleaning-department head Jos van Bedaf remembered his 1960s army service, where someone had drawn a small dot in a latrine urinal — and that latrine stayed cleaner than the others. Schiphol etched a fly by the drain: give men a target and they aim. A fly, van Bedaf reasoned, is the one animal nobody minds hitting.

A cleaning manager who remembered a barracks trick had a fly etched by the drain: give men something to aim at and they aim.

Etched a fly by the drain so men's involuntary targeting reflex aims at it, cutting spillage without needing anyone to read or comply with a sign.

A visible target near the drain automatically draws men's aim, reducing spillage without conscious effort.

The fly taps an innate pest-aiming instinct, so no reading or decision is required to comply.

Unlike signs, the target works before conscious thought, so it doesn't rely on willingness to change.

The effect is strongest when the target is placed exactly where aim needs correcting, as Schiphol did.

To change a stubborn behavior, don't ask people to try harder; give their existing instincts a concrete target that makes the right action automatic.

Spillage reportedly fell ~80% and cleaning costs ~8% (the figures are 'very empirical', by their own admission). Thaler's favourite nudge; copied worldwide. Richard Thaler calls it his favourite illustration of a nudge — make the right thing easier rather than the wrong thing impossible. The 80% spill reduction was, by the team's own admission, 'very empirical'; the fly conquered the world's airports anyway, and urinal targets are now an industry.