Case study of
#00083 Social-norm messaging and management of environmental cues
Petrified Forest National Park, Arizona, USA
#00112
Implementer
Cialdini et al. (field experiment), Petrified Forest National Park
Location
Description
A controlled field experiment by Cialdini and colleagues at Petrified Forest National Park tested anti-theft signage on visitor paths where marked pieces of petrified wood were placed. A sign stressing a negative descriptive norm — that many past visitors had removed wood — increased theft relative to no sign. A prohibitive sign stating the injunctive norm ('Please don't remove the petrified wood…') produced the lowest theft rate. This demonstrates the same norm-messaging lever backfiring when it broadcasts how common the undesirable behaviour is.
Metrics
2Lessons learned
- A message that emphasises how many people currently litter or steal can backfire by normalising it — the 'many visitors take wood' sign nearly tripled theft (7.92%) versus the no-sign control (2.92%).
- Effective cue management states the injunctive norm (what one should do) rather than broadcasting a negative descriptive norm (what many people actually do) — the injunctive sign reduced theft to 1.67%.
- Framing, not just the channel, determines the outcome: the same norm-messaging lever produced opposite results depending on whether it highlighted common bad behaviour or prohibited it.
Links
1Documented Jun 27, 2026