sentences:  The third imperative is to maintain a span size that is appropriate to the reading conditions.The span must not be so small that there is insufficient time to perceive visual input and process it into musculoskeletal commands; it must not be so large that the capacity of the memory system to store and process information is exceeded.Musicians appear to use oculomotor commands to address all three imperatives simultaneously, which are in effect mapped onto each other in the reading process.