We evaluate Richard Posner's famous hypothesis that common law converges to efficient legal rules using a model of precedent setting by appellate judges. Following legal realists, we assume that judicial decisions are subject to personal biases, and that changing precedent is costly to judges....

"We present a theory of choice among lotteries in which the decision maker's attention is drawn to (precisely defined) salient payoffs. This leads the decision maker to a context-dependent representation of lotteries in which true probabilities are replaced by decision weights distorted in favor...