In-group and out-group biases in the marketplace: a field experiment during the World Cup
通过在巴西世界杯期间对电子市场进行审计研究，发现卖家对外国人收取更高价格，但未对穿对手球队球衣的买家歧视；仅当巴西队刚获胜时，穿巴西队球衣的买家获得更低价格，表明存在基于偏好的内群体偏爱。
We investigate the effects of group identity on discrimination by conducting an audit study in electronics markets in São Paulo, Brazil during the 2014 Brazil World Cup (WC). We manipulated buyers' group membership, by making them wear shirts of national football teams, and exploit the outcomes of the WC matches, which arguably affected the salience of sellers' group identity. Although we find that foreigners are overcharged, we do not detect discrimination against buyers wearing a rival team shirt. In contrast, we do detect in-group market favouritism (i.e., lower prices) towards buyers wearing the Brazil shirt when Brazil had won a match in the very recent past. Our analysis rejects the explanation that sellers' behaviour were always motivated by economic profits. Instead, the results indicate taste-based discrimination (Becker, 1957) and shed light on the ways in which in-group and out-group biases occur in market outcomes.