2 groups of experienced monkeys were given 320 6-trial discrimination problems in which 1 of 2 objects present on Trial 1 was replaced by a new object on Trials 2-6. For one group the new object replaced the one chosen on Trial 1; for the other group, it replaced the object not chosen on Trial 1. While the latter group showed high percentages of correct responses on Trial 2 regardless of whether or not Trial 1 choices were rewarded, the former group showed only chance performance on Trial 2. It was concluded that, in displacing 1 of 2 objects. S acquires useful response tendencies attached to the displaced object only. (PsycINFO Database Record (c) 2006 APA, all rights reserved)