INGROUP FAVORITISM IN UMPIRING DECISIONS IN AUSTRALIAN FOOTBALL

In 171 Australian rules football matches over a period of 4 years, ump ires' allocations of rewards to (a) teams from the same state (instate ) as the central umpires and (b) teams from other states (outstate) we re examined. The instate teams received significantly more rewards (fr ee kicks) than the outstate teams did in matches between them. The ext ent of the instate adjudication advantage varied by year; it was signi ficantly greater for matches on an instate home ground than for matche s on an outstate home ground. The umpires manifested ingroup favoritis m in rewards of low value-salience (obstruction of outgroup scoring op portunities) rather than in rewards of high value-salience (facilitati on of ingroup scoring opportunities).