A hierarchy of computing modules is configured to (i) learn a cause of input data sensed over space and time, and (ii) determine a cause of novel sensed input data dependent on the learned cause. When determining the cause of the novel sensed input data, the computing modules determine likely sequences based on observed inputs. Information identifying one or more of those likely sequences and indexes of observed elements in those sequences may then be stored in external memory to facilitate data compression and/or granularity-based searches.