A method of testing a subject's competence for operating machines by successively presenting a plurality of pages of scattered images to the subject, having the subject establish a path through the scattered images on each of the plurality of pages, recording the absolute time required for the subject to establish the path through the scattered images on each of the plurality of pages, determining the relative time required for the subject to establish the path on at least two of the plurality of pages of scattered images, and classifying the subjects competence for operating machines based on the absolute time and the relative time.