Extinction and blocking of conditioned inhibition in human causal learning.

Two experiments investigated extinction and blocking of a conditioned inhibitor in a human contingency-learning task. Lotz and Lachnit (2009) and Melchers, Wolff, and Lachnit (2006) reported extinction of inhibition only when participants experienced outcome levels lower than those used in training. In Experiment 1, which used more neutral instructions than the previously mentioned studies, we found that extinction of inhibition occurred, whether or not participants experienced lower outcome levels. In Experiment 2, we applied this outcome manipulation to blocking of a conditioned inhibitor. We found blocking of inhibition both when participants had experience with lower outcomes and when they did not. The results of our two experiments are consistent with Rescorla and Wagner's (1972) associative model, and inconsistent with an inferential account of causal learning (De Houwer, Beckers, & Vandorpe, 2005).