Econ 101 1st EditionFinal Exam Study Guide Lectures: 20-26 What is mental Imagery?-Based on (likely) responses to the questions in the beginning, it seems plausible that wehave the capacity to experience the external world with out minds-Defined as “the ability to recreate the sensory world in absence of physical stimuli-Having a perceptual experience, and being able to recreate that perceptual experience without the actual sensory information-Rememer the picture of homer simpson thinking about the donut?-Is not just visual…-Auditory, gustatory, tactile-Also has a role in prospection-Think about what this class will be like the next time we meet…History-Capacity for mental imagery has long intrigued mankind-Aristotle-Wundt-Imagery was one of the basic elements of consciousness-Along with sensations and feelingsHistory – Imageless thought debate-Are images necessary for thought?-Wundt & Aristotle – thought cannot occur without images-Galton – Thought does not rely on images-Observed individuals who could not form images, but could still think-Imageless thought debate ended with the advent of behaviorism-Mental images are not objective and measureable-No longer studied by psychologists-Cognitive psychology renewed scientific interest in mental imageryConceptual Peg Paivio (1965, 1965)Paired associate learning-Concrete pair: Truck Tree-Abstract pair: Truth Justice-Test: Truck ?-Paivio found a memory advantage for concrete nouns-Conceptual peg hypothesis: Concrete nouns create mental images that other words can be associated with-Imagining a picture of a truck will lead to recall of the image of a truck-The recall of the image truck provides a place to recall the tree in their mind-Dual Coding Theory: Two specialized subsystems-One for languages: uses logogens-One for images: uses imagensMental Rotation Shepard & Metzler (1971)-Can people tell whether images are the same or different when they are rotated to different orientations?-Presented 3D figures with a 3D appearance-Varied complexity of pair-Images rotated in 360 degree picture plan-Images rotated by perspective of depth-Measured reaction time in same/different task-What do you think they foundShepard & Metzler (1971)-More rotation of picture led to long reaction times for same/difference judgment-Self-reports: mentally rotated the images to make judgment-Reaction time: more mental rotation needed. Longer reaction times-Concluded that people were able to mentally rotate images during task as they would inthe real worldMental Scanning Kosslyn (1973, 1978)-General procedure-Memorize an image-Accurately reproduce it-Given name of picture and told to imagine a part of it-Look for another part of the image-Respond true if they could locate it-False if they could not locate it-Measure reaction time to make judgmentKosslyn (1973)-Imagery or verbal conditions-Imagery: memorize image then reproduce it-Verbal: describe the pictures memorize the description-Focused on whole conditions-Whole: memorize the entire picture-Focused: pay attention to a part of the picture during memorizationExample search taste (boat)-True: focus on the anchor. Search for the motor-False: focus on the anchor. Search for the sail-Has to respond if the second object was present in the image or not with judgment-Found that images led to faster reaction times than verbal-Focused led to faster reaction times for image, larger disparity for verbal-Conclusions:-Can selectively retrieve information from an internally generated image-The time to do this varies as a function of distance on actual image-Difference in RTs seems to rely on encoding the spatial layout of imageKosslyn et al. (1978)-Learn locations of objects on map-Asked:-Image a black dot going from the hut to the tock-Rock could be true or false as in Kosslyn (1973)-Measured reaction times for true/false judgments-What do you expect they found?-Found a linear increase in reaction time for an increase in distance-Suggests that mental imagery maintains the spatial relationships as the actual image-Effect only occurs when individuals are asked to consult images -Disappears when images are not consulted Size in visual Field Kosslyn (1975)-Interested if context affected imagery-Procedure:-Imagine animals-Judge true or false if a listed property was part of the animal-Elephant has tusks (True)-Rabbit has wings (false)-Measured reaction time ot make judgments-Varied relative sizes of animalsResults:-Longer reaction times for small animals in the same context as large animals-Less detail in small animal; longer reaction time to make judgement-Shorter reaction times for larger animals in same context as small animals-More detail in large animal; shoter time to make judgment-Same parrter of results when told to image a large fly and small elephant-Results are from manipulation of imagined animal size, not knowledge about animal-Conclusion:-Differences in size are represented in mental images-Context (paired animal) determined reaction time-Detail was a function of size in imagined image-Imagery is similar to perceptionMental Walk Kosslyn (1978)-Does imagery function the same way as perception?-Procedure-Imagine an animal that is far away-Given height of animal and distance to image it at -Animals were different sizes-Imagine walking towards that object-Say when animal seems to overflow from the imagined scene-How much distance did you travel before the image overflowed?-Results:-Found that less distance needed to be “walked” for larger animals to overflow form the imagined scene-More distance needed to be “walked” for smaller animals to overflow from scene-Conclusion:-Limited space to imagine something-Short term memory: “visual buffer”-Image space was more detailed at its center-Imagery functioned similar to perception-The research we have been discussing lays the groundwork for Kosslyn’s theory of mental imageryThe crux of the mental imagery debate-We have the capacity for mental imagery but….-Is it spatial or propositional?-What is the basic representation?-Is mental imagery the primary representation, and propositions a re-representation?Or-Are propositions the underlying representation and an image recreated from the propositionsKosslyns’s Spatial/analogue account-Theory if imagery: embodied by a computational model-Visual images are represented spatially, in a special mental medium-4 properties of spatial medium-Specified sashaped and ability to depict