How do we learn causal relations between events from experience? Many have argued for an associative account inspired by animal conditioning models, but there is a growing literature arguing that indirect effects in contingency learning depend on explicit cognitive processes. Our experiments explore the basis of two such effects: blocking and screening off. In Experiment 1, we gave participants an untimed explicit prediction task to replicate standard findings in the contingency learning literature in a novel domain. We obtained robust indirect effects when participants had a causal framework to constrain their reasoning. In Experiment 2, we reduced the time available for explicit recollection by reconstructing the task as a fast-paced RT task. Participants continued to show robust learning of direct relationships, as measured by response times, but there were no indirect effects. Experiment 3 followed up on whether participants in our RT task would produce indirect effects through explicit processes when given an opportunity to make a more deliberative prediction at test.