Goldstein, Cialdini, Griskevicius 2008 (JCR) — provincial descriptive norms ("guests in this room") outperform general descriptive norms; reference-group proximity matters

Claim: Goldstein, Cialdini, and Griskevicius (2008) ran two field experiments in hotels and found:

• Descriptive norms about towel reuse outperformed traditional environmental appeals.
• Provincial descriptive norms ("the majority of guests in this room reuse their towels") outperformed general descriptive norms ("the majority of guests reuse their towels").

Descriptive norms function as decision shortcuts only when the reference group is similar enough to the chooser that the norm is informative.

Source: Goldstein, N. J., Cialdini, R. B., & Griskevicius, V. (2008). "A Room with a Viewpoint: Using Social Norms to Motivate Environmental Conservation in Hotels." Journal of Consumer Research 35(3): 472–482. https://academic.oup.com/jcr/article/35/3/472/1856257

Confidence: Verified, applied inference for this buyer.

For Candid: A marketing-agency case study from a SaaS company is not social proof for a Kitchener mid-size framer. A case study from another Kitchener-Waterloo-Cambridge GC — same size, same trade, same year — is. The closer the reference is to the buyer's own coordinates (geography, trade, business size, year), the higher the persuasive yield.

Operationalized as: [[rule-radius-matched-peer-social-proof-only]].