A computerized sequential event sampling decision-making task was administered to 187 5- to 10-year-olds and adults. Participants made a series of choices between alternatives that differed in win probability (Study 1) or win and loss probability (Study 2). Intuitive and more explicit measures were used. Study 1 revealed that, across ages, participants demonstrated intuitive sensitivity to probability; however, adult participants evidenced greater sensitivity than did children, and younger children failed to demonstrate more explicit understanding of probability. Study 2 also revealed that children were intuitively sensitive to probability; however, the inclusion of loss had limited impact on decision processes. These findings and their relevance to cognitive developmental theory are discussed.