Visual Imagery

Cognition Chapter 10 Visual Imagery Visual imagery: Seeing in the absence of a visual stimulus Mental imagery: Refers to the ability to re-create the sensory world in the absence of physical stimuli. Is used to include all of the senses. Auditory imagery: Hearing things in the absence of sound History of imagery Imageless thought debate: The debate between those who believe that thought is impossible without an image and others contending that thinking can occur without images 1950s and 1960s became known as the cognitive revolution Paired-associate learning: Participants are presented with pairs of words, like boat-hat or carhouse, during a study period. They are then presented during the test period with the first word of each pair, their task is to recall the word that was paired with it during the study period Conceptual peg hypothesis: Concrete knowns create images that other words can hang onto. - Ex: presenting the pair boat-hat, creates an image of a boat then presenting the word boat later will bring back the boat image. Mental chronometry: Determining the amount of time needed to carry out various cognitive tasks. - Their task was to be given two objects and within a certain amount of time given they had to decipher whether they were the same objects or not. Mental images differ from perception in that they are not as vivid or long lasting, imagery shares many properties with perception. Mental scanning: The idea that there is a spatial correspondence between imagery and perception. - Participants create mental images and then scan them in their minds. Imagery debate: A debate about whether imager is based on spatial mechanisms such as those involved in perception or on mechanisms related to language called propositional mechanisms. Spatial representations: Representations in which different parts of an image can be described as corresponding to specific locations in space Proposed by Kosslyn Epiphenomenon: Something that accompanies the real mechanism but is not actually part of the mechanism - Proposed by Pylyshyn Propositional representations: Representations in which relationships can be represented by abstract symbols such as an equation or a statement such as “the cat is under the table” Depictive representations: Spatial representations such as the picture of the cat under the table in which parts of the representation correspond to parts of the object. Mental walk task: In which they were to imagine that they were walking toward their mental image of the animal. Their task was to estimate how far away they were frim the animal when they began to experience “overflow” when the image filled the visual field or when its edges started to become fuzzy. - This provided further evidence for the idea that images are spatial just like perception Very many neuron recordings have been carried out on animals however very few have been carried out on humans Imagery neurons: neurons that go off due to imagery - These neurons respond in the same way to perceiving an object and to imaging it, meaning that there is further evidence to suggest that there is a close relation between perception and imagery Topographic map: Specific locations on a visual stimulus cause activity at specific locations in the visual cortex and points next to each other on the stimulus cause activity at locations next to each other in the cortex. Removing part of the visual cortex reduces size of her field of view so the horse filled up when she was farther away. - This resulted in evidence that the visual cortex is important for imagery Unilateral neglect: Caused by damage to the parietal lobes, in which patient ignores objects in one half of the visual field even to the extent of shaving just one side of his face or eating only the food on one side of her plate. Double dissociation example: When people are unable to identify faces but are able to identify objects Visual agnosia: Patient was able to identify parts of the object such as a dart or a tennis racket but was unable to identify it as a whole meaning its name. This is double dissociation. Method of Loci: A method in which things to be remembered are placed in different locations in a mental image of a spatial layout. Pegword technique: Involves imagery as in the method of loci but instead of visualizing items in different locations you associate them with concrete words. - Create a list of nouns, one-bun, two-shoe, three-tree, its easy to remember these words in order because they were created by rhyming them with numbers Rhyming is also a retrieval cue that helps remember each word Spatial imagery: Refers to the ability to image spatial relations such as the layout of a garden Object imagery: Refers to the ability to image visual details, features, or objects, such as a rose bush with bright red roses in the garden Paper folding test (PFT): Designed to measure spatial imagery: Participants saw a piece of paper folded and then pierced by the pencil. Their task was to pick from 5 choices what the paper would look like when unfolded Vividness of visual imagery questionnaire (VVIQ): Designed to measure object imagery - Participants rated on a 5 pt scale, the vividness of mental images they were asked to create - A typical item: The sun is rising above the horizon onto the hazy sky These demonstrated differences between participants with a low score of the PFT (low spatial imagery) and participants with a high score (high spatial imagery) 62% of those who had low scores on spatial imagery had high scores on the VVIQ meaning they had high object imagery, whereas 51% of the high spatial imagers had low scores on the VVIQ meaning they had low object imagery. Degraded pictures task: Consisted of a number of degraded line drawings Mental rotation task: Required participants to judge whether pictures such as the degraded picture were two views of the same object or mirror-image objects. Spatial imagers did better in the mental rotation task, and object imagers did better on the degraded imagers task.