  This paper investigates learning effects and human operator training
practices in variable autonomy robotic systems. These factors are known to
affect performance of a human-robot system and are frequently overlooked. We
present the results from an experiment inspired by a search and rescue scenario
in which operators remotely controlled a mobile robot with either
Human-Initiative (HI) or Mixed-Initiative (MI) control. Evidence suggests
learning in terms of primary navigation task and secondary (distractor) task
performance. Further evidence is provided that MI and HI performance in a pure
navigation task is equal. Lastly, guidelines are proposed for experimental
design and operator training practices.
