Percent choice of the risky option in the amount (A, N = 9) and delay (B, N = 10) gambling tasks. Sigmoid curves were drawn based on logistic functions that were fitted to observed values (r² > 0.99 in both tasks). When the risky and sure options had the same expected value (x = 2 in the amount gambling task, x = 5 in the delay gambling task), rats significantly preferred the risky option (p < 0.05, both tasks). Calculated from sigmoid logistic functions, the subjective equivalence points between risky and sure options were 2.4 in the amount gambling task and 2.3 in the delay gambling task. Error bars indicate SEM.