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The percentage of correct choices for individual pigeons on arbitrary (AB) matching-to-sample baseline trials (solid bars) and symmetry (BA) test trials (hatched bars). From “A test of symmetry and transitivity in the conditional discrimination performances of pigeons”, by R. Lipkens, R. F. M. Kop, and W. Matthijs, 1988, Journal of the Experimental Analysis of Behavior, 49, p. 405. ©1988 by the Society for the Experimental Analysis of Behavior.
