2003: Serial expertise of rhesus macaques

experimentally naive rhesus monkeys that learned, by trial and error, the correct order in which to respond to 3-, 4-, and 7-item lists of arbi-trarily selected photographs. The probabilities of guessing the correct sequence on 3-, 4-, and 7-item lists were, respectively, 1/6, 1/24, and 1/5,040. Each monkey became progressively more efficient at deter-mining the correct order in which to respond on new lists. During sub-sequent testing, the subjects were presented with all possible pairs of the 28 items used to construct the four 7-item lists (excluding pairs of items that occupied the same ordinal position in different lists). Sub-jects responded to pairs from different lists in the correct order 91 % of the time on the first trials on which these pairs were presented. These features of subjects ’ performance, which cannot be attributed to pro-cedural memory, satisfy two criteria of declarative memory: rapid acquisition of new knowledge and flexible application of existing knowl-edge to a new problem