Causality is an important aspect of how we construct reality. Yet, while many psychological phenomena have been studied in their relation to virtual reality (VR), very little work has been dedicated specifically to causal perception, despite its potential relevance for user interaction and presence. In this paper, we describe the development of a virtual environment supporting experiments with causal perception. The system, inspired from psychological data, operates by intercepting events in the virtual world, so as to create artificial co-occurrences between events and their subsequent effects. After recognizing high-level events and formalizing them with a symbolic representation inspired from robotics planning, it modifies the events’ effects using knowledge-based operators. The re-activation of the modified events creates co-occurrences inducing causal impressions in the user. We conducted experiments with fifty-three subjects who had to interact with virtual world objects ...