This paper reports the results of an experiment that was designed to t
est the impact of fairness on market prices. Prices were determined in
a one-sided oral auction, with buyers as price-makers. Upon acceptanc
e of an offer, sellers determined the quality of the good. Buyers offe
red prices that were substantially above the market-clearing level and
expected sellers to respond with high quality levels. This expectatio
n was, on average, confirmed by the behavior of sellers. These results
provide, therefore, experimental support for the fair wage-effort the
ory of involuntary unemployment.