Convergent results in eyeblink conditioning and contingency learning in humans: addition of a common cue does not affect feature-negative discriminations.

Previous human discrimination learning experiments with eyeblink conditioning showed that an increase in the similarity between the to-be-discriminated stimuli had no effect on the rate of learning. This result was at variance with data from other experiments which had used different paradigms and different stimulus materials. We therefore compared human discrimination learning in eyeblink conditioning and contingency learning using carefully matched procedures. Participants learned two feature-negative discriminations, A+/AB- and CD+/CDE-. Convergent results were obtained in both paradigms. Adding a common cue did not affect response differentiation, i.e. the A+/AB- discrimination and the CD+/CDE- discriminations were equivalent. These results support the notion that learning in both paradigms is based on the same principles. However, the overall pattern of results cannot be easily accommodated within associative learning theories based on the Rescorla-Wagner Model or on Pearce's Configural Model. The application of these models to current and previous data is discussed.