eg. fusiform face area
--> comparing activity with faces (what they are interested in
-----> but also faces vs objects,faces vs vegetables, faces with houses, scrambled faces, faces with body parts, faces with animals ETC...!!!
--> by doing this and substracting everything they can make a good argument, that indeeed its only ever active for faces !! cause literally all other bjects have been zeroed out :D !!
--> kinda clever haha