Abstract
In the predictive learning and causal reasoning literature it has been suggested that the processing of events is under the control of a competitive mechanism. However, little is known about whether the competitive mechanism operates at the encoding or near the response stages. The present work suggests that measures based on the recall of frequencies of the cells in the contingency table could help us in the placement of the competition principle within the processing stages. As the contingency judgment about a constant symptom-illness relation changed according to the validity of a second different symptom, we concluded in favour of a competition mechanism. However, estimated frequencies did not change as a result of such manipulation. This dissociation suggests that the competitive mechanism operates near the response stage rather than at the stimulus encoding period