Ice Age dice may indicate early Native Americans understood probability

A study in American Antiquity reports two-sided gaming pieces used by Native Americans at least 12,000 years ago and identifies 565 confirmed dice artifacts from across North America.

Researchers report that Native Americans used two-sided dice in games of chance more than 12,000 years ago. The finding appears in American Antiquity and is led by Robert Madden, a graduate student at Colorado State University. Madden adapted criteria from early ethnographic work to identify gaming pieces across published archaeological collections. The oldest confirmed examples come from Folsom deposits in Wyoming, Colorado and New Mexico, dated to the end of the last Ice Age. Key findings: - Madden developed four diagnostic criteria, adapted from Robert Stewart Culin’s 1907 study, to recognize two-sided dice in the archaeological record. - He identified 565 confirmed dice from 45 sites and designated 94 additional artifacts as probable dice. - The artifacts are typically two-sided “binary lots” that fall into four shape categories: flat, plano-convex, convex-concave, and convex-convex. - Items with drilled holes or whose sides were only distinguishable by subtle shape were excluded as uncertain to avoid misidentifying beads or decorative objects. - The oldest confirmed pieces come from Ice Age (Folsom) deposits dated to about 12,000 years ago, predating known Old World dice by millennia. - Madden describes the games as social, one-on-one exchanges rather than house-banked gambling, and notes they likely supported reciprocal relationships between groups. Summary: The paper moves the earliest clear evidence for intentional use of repeatable random outcomes in North America to the end of the last Ice Age and argues that Native American groups deliberately produced and used such objects in rule-based games. The authors suggest this shifts how scholars should view the origins of probabilistic thinking and recommend further comparative study of late Ice Age material in the Old World to reassess the global history of such practices.