| Abstract: | In laboratory experiments the representativeness heuristic has been shown to affect participants' judgments. Finding representativeness in a real-world economic market would indicate that even decision makers who are highly experienced and motivated use the heuristic, and would, in addition, violate the efficient market hypotheses, i.e. the theory that market prices fully reflect all available information. Testing for representativeness in the market for bets on National Football Leagues games avoids complications that make tests of representativeness in a stock market difficult to interpret. Evidence for representativeness in the NFL betting market is found in a data set from an earlier study which failed to test for representativeness, and in the 1976– 9 market. Representativeness does not appear to exist in the contemporary market, however, perhaps because with the advent of the personal computer the market depends less on purely human judgment. |
