UMMS Affiliation

Shriver Center

Publication Date


Document Type



Discrimination Learning; Cebus


Mental and Social Health | Neuroscience and Neurobiology | Psychiatry and Psychology


A “second generation” matching-to-sample procedure that minimizes past sources of artifacts involves (1) successive discrimination between sample stimuli, (2) stimulus displays ranging from four to 16 comparisons, (3) variable stimulus locations to avoid unwanted stimulus-location control, and (4) high accuracy levels (e.g., 90% correct on a 16-choice task in which chance accuracy is 6%). Examples of behavioral engineering with experienced capuchin monkeys included four-choice matching problems with video images of monkeys with substantially above-chance matching in a single session and 90% matching within six sessions. Exclusion performance was demonstrated by interspersing non-identical sample-comparison pairs within a baseline of a nine-comparison identity-matching-to-sample procedure with pictures as stimuli. The test for exclusion presented the newly “mapped” stimulus in a situation in which exclusion was not possible. Degradation of matching between physically non-identical forms occurred while baseline identity accuracy was sustained at high levels, thus confirming that Cebus cf. apella is capable of exclusion. Additionally, exclusion performance when baseline matching relations involved non-identical stimuli was shown.

DOI of Published Version



Brino, A. L. F., Assumpção, A. P. B., Campos, R. S., Galvão, O. F., & McIlvane, W. J. (2010). Cebus cf. apella exhibits rapid acquisition of complex stimulus relations and emergent performance by exclusion. Psychology and Neuroscience, 3(2), 209-215. Link to article on publisher's site

Journal/Book/Conference Title

Psychology and Neuroscience