Provisual actions are movements used to facilitate vision.
They have been studied with computer-generated images of two objects presented side by side. Subjects judged which had a target property, with or without the opportunity to adjust the orientation of the objects in depth. Also, although objects are generally moved towards the frontoparallel position in active conditions, judgments are made well before it is reached. This suggests that subjects balance multiple indications to establish when they have achieved a good enough view to make a judgment. Decision times and subjective reports clarify the movements used.