Abstract
Two studies compared choice and underlying cognitive processes in equivalent decision tasks involving risk and uncertainty (lotteries versus sports gambles including displayed expert probability judgments). In sports gambles, background knowledge was triggered via information on team location, home or away. Otherwise, displayed risk information (stake, winnings, odds and outcome probabilities) was controlled across gamble type. In a choice study, home win bets were chosen significantly more frequently than draws or away wins, compared to lottery equivalents. In a parallel study eliciting concurrent verbal protocols, participants made fewer evaluations of odds and probabilities, and more statements involving background knowledge in sports gambles. Furthermore, some sports gamble protocols indicated modifications of stated probabilities and decision strategies contingent on domain knowledge. It was concluded that stated probability revision and knowledge-based reasoning are key cognitive processes in sports gambling not normally applied in the lottery paradigms often employed in decision research.