Causal Induction in the Presence of a Perfect Negative Cue: Contrasting Predictions from Associative and Statistical Models Fre Âde Âric Valle Âe-Tourangeau and Robin A. Murphy University of Hertfordshire, Hat®eld, Hertfordshire, U.K. A. G. Baker McGill University, Montreal, Quebec, Canada Two experiments on human causal induction with multiple candidate causes are reported. Experiment 1 investigated the in¯uence of a perfect preventive cause on the ratings of a less contingent cause. Whereas the Rescorla±Wagner model (RWM) and Cheng’s probabilistic contrast model predict that the less contingent cause should be completely discounted, the Pearce model predicts, in most cases, an enhancement of that cause’s perceived importance. Results corresponded more closely to the predictions of the Pearce model. The predictions of both the RWM and the Pearce model rely on a constant context cue acquiring associative strength, yet no such cue was explicitly identi®ed in the task scenario employed in Experi- ment 1. Experiment 2 replicated a number of key conditions of Experiment 1 with a task scenario that afforded ratings of the causal importance of the context in which the effective- ness of the discrete candidate causes was evaluated. In addition, the number of trials was increased to test the possibility that the ratings in Experiment 1 were the product of incom- plete learning. The results of the ®rst experiment were replicated and the ratings of the effectiveness of the context cue were anticipated by both the RWM and the Pearce model. Overall, the Pearce model offers a more comprehensive account of the causal inferences recorded in this study. In a causal induction task a number of candidate causes may precede the occurrence or absence of a target outcome. The nature of the inductive inferences supported by one such candidate cause is in part determined by its predictive value as de®ned by the difference between the probability of the outcome given its presence, P(O| C), and given its absence, P(O | 2C), an index termed DP (Shanks, 1995). However, research using both THE QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY, 1998, 51B (2), 173±191 Requests for reprints should be sent to Fre Âde Âric Valle Âe-Tourangeau, Department of Psychology, University of Hertfordshire, Hat®eld, Hertfordshire, AL10 9AB, U.K. E-mail: psyqfv@herts.ac.uk. This work was supported in part by ESRC Grant R000221514 awarded to FVT. We thank Susan Drew and Stephen Curley for recruiting and running the participants. We also thank John Pearce and two anonymous reviewers for constructive comments on an earlier version of this manuscript. Ó 1998 The Experimental Psychology Society