Fig 2. Procedures for Experiment 2.

(A) Ranking of line drawings was performed by re-arranging images printed on cardstock on a large table. Participants were instructed to first rank five randomly chosen drawings, and to then insert subsequent drawings at the appropriate position. (B) Constructing a super-reference. The highest-ranked drawing served as the initial reference. The other drawings were matched to the reference in ranking orders. Unmatched contours were added to the reference, eventually yielding a super-reference that contains the super set of contours from all drawings. Original photograph under Creative Commons License by Flickr user Cyndy Sims Parr.