In Experiment 1 (1a and 1b), Rhesus monkeys (Macaca mulatta) learned lists of two-choice visual discriminations in which list position was relevant to discrimination performance. For example, Stimulus A was the rewarded stimulus if it was presented at List Position 1, but was not rewarded if it was presented at any other position in the list; similarly, Stimulus B was rewarded only at List Position 2, and so on. In learning these lists, all animals showed a marked primacy effect. In Experimen...