SIMILARITY AND DISCRIMINATION-LEARNING

The role played by similarity in discrimination learning was examined in four experiments using compound stimuli. In Experiment 1, pigeons r eceived training in which food was presented after stimulus A, compoun d AB, but not compound ABC-A+ BC+ ABCo. The A+ ABCo discrimination was acquired more readily than was the BC+ ABCo discrimination. In the re maining experiments, training was of the form, A+ B+ C+ AB+ AC+ BC+ AB Co. The discrimination between the single stimuli A+ B+ C+ and ABCo co nsistently developed more readily than between the pairs of stimuli AB + AC+ BC+, and ABCo. The results are shown to be more consistent with a configural than with an elemental theory of conditioning.