Conditional discrimination responding in non-humans

Behaviour analysis employs the matching-to-sample procedure to study conditional discrimination responding in non-humans. A brief analysis of the studies to date is given with an emphasis on current research conducted in the Cork Laboratory employing naturalistic, or multi-modal, stimuli. The growing research area of stimulus equivalence is documented and the various studies that have failed to demonstrate derived responding in nonhumans are outlined. Finally, methodologies for facilitating stimulus equivalence, or one of its properties, symmetry are described. The most efficient procedures are suggested as those that involve explicitly training symmetrical relations across multiple exemplars of naturalistic stimuli.