Introduction to Cognitive Psychology - Department of Psychological ...

Professor Greg Francis 8/14/12Representation of mental imagesImagine you have a mental image of a lion If the mental image is a description (set ofpropositions), then it should include descriptiveinformation (head, mane, ears, whiskers,, tail,…)» size of body parts shouldnt matter much(except as information in the proposition)Representation of mental imagesImagine you have a mental image of a lion If the mental image is a depiction, then it shouldinclude factors such as head, mane, ears, and theirsizes and relative positions» self reports of mental images suggest thedepicted version, but how to measureexperimentally?Purdue UniversityPurdue UniversityRepresentation of mental images Kosslyn (1976) Ask subjects to quickly answer questions like:» Does a lion have a head? (big body part)» Does a lion have claws? (small body part) subjects in two groups» 1) form a mental image of a lion» 2) think about a lion, but without a mental image Subjects forming a mental image respond more quickly to the headquestion than the claw question» presumably because the head is bigger in the mental imageRepresentation of mental imagesSubjects that did not form a mental image respond more quicklyto the claws question than the head question presumably because the propositions about a lion having claws aremore accessible in some network of propositionsSo, different ways of thinking about a lion can lead to differentpatterns of access to information which implies mental images are different than propositions16001600Reaction time (ms)140012001000800600400200ImageryNo imageryReaction time (ms)140012001000800600400200ImageryNo imagery0SmallpartBig partPurdue University0SmallpartBig partPurdue UniversityMental rotationShepard & Metzler(1971) 3-D shapes rotated in plane or in depthCogLab experiment 163 participantsThe more rotated thestimuli are, the longerit takes to make aresponseMental rotation decide if shapesare same aredifferent close to linear increasein RT measure time todecidePurdue UniversityPurdue UniversityPSY 200: Intro. to Cognitive Psychology 3