WEIRD samples
Western, Educated, Industrialised, Rich, Democratic samples.
What it is
Henrich, Heine & Norenzayan (2010) coined WEIRD to describe the demographic of most psychology and social-science samples: Western, Educated, Industrialised, Rich, Democratic — often US college undergraduates. Many cognitive and behavioural patterns that look universal in WEIRD samples turn out to be culturally specific, sometimes wildly so (the Müller-Lyer illusion, ultimatum-game offers, attribution styles, perceptual organisation).
Why a reviewer cares
Reviewers ask: who is your sample? If your conclusion is 'humans do X', does the evidence support that breadth or only 'a particular sample of US undergraduates do X'? Online platforms (MTurk, Prolific) help with size but not with WEIRDness — they're often disproportionately white, US, and college-educated.
How to fix it
Report the demographic composition of your sample. Scope your claims to the population sampled, not 'humans'. Where universal claims matter, replicate in non-WEIRD samples. If you can't, mark the generalisation as a limitation explicitly.
This is one of ~15 canonical methodology explainers Paper Review's red-team report links to. To get a full review of your manuscript, start a Paper Review — $5.