Humans and monkeys tested on recursion (IMAGE) University of California - Berkeley Caption Scientists tested Bolivia's indigenous Tsimane' people (bottom left), U.S. adults and children and macaque monkeys on their thinking patterns when arranging sequences. (Photo courtesy of Stephen Ferrigno) Credit Photo courtesy of Stephen Ferrigno. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.