1. A method for training a system to identify state changes in objects in virtual worlds, the method comprising: observing a group of one or more base events; determining by a computer processor that the group of one or more of the observed base events is correlated to a candidate higher-level event, the candidate higher-level event including at least some of the observed base events, wherein determining that the group of one or more of the observed base events is correlated to the candidate higher-level event is based at least in part on statistical analysis of the observed base events; receiving user input confirming that the group of base events is correlated to the candidate higher-level event; and if the received user input specifies that the group of base events is correlated to the candidate higher-level, storing the candidate higher-level event as an identified higher-level event.