Visual Imagery - Topic 10 PDF

VISUAL IMAGERY  Visual Imagery is seeing in the absence of a visual stimulus. Mental Imagery is a broader term that refers to re-create the sensory world in the absence of physical stimuli, is used to include all senses.  EARLY IDEAS ABOUT IMAGERY Wundt proposes that images...

VISUAL IMAGERY  Visual Imagery is seeing in the absence of a visual stimulus. Mental Imagery is a broader term that refers to re-create the sensory world in the absence of physical stimuli, is used to include all senses.  EARLY IDEAS ABOUT IMAGERY Wundt proposes that images were one of the three basic elements of consciousness, along with sensations and feelings. He also proposed that images accompany thought, studying images as a way of thinking. The idea of a link between imagery and thinking gave to the imageless thought debate, with some psychologists taking up Aristotle’s idea that “thought is impossible without an image” and other contending that it can occur that thinking can occur without images. Evidence supporting the idea that imagery was not required for thinking was Francis Galton’s (1883) observation that people who had great difficulty forming visual images were still quite capable of thinking.  IMAGERY AND COGNITIVE REVOLUTION One of the keys to the success of this “revolution” (1950’s – 1960’s) was that cognitive psychologists developed ways to measure behavior that could be used to infer cognitive processes. One example of a method that linked behavior and cognition is Alan Paivio’s (1963) work on memory. Paivio showed that it was easier to remember concrete nouns, like truck or tree, that can be imaged than it is to remember abstract nouns, like truth or justice, that are difficult to image. One technique Paivio used was paired-associate learning.  PAIRED-ASSOCIATE LEARNING In a paired-associate learning experiment, participants are presented with pairs of words, like boat–hat or car–house, during a study period. They are then presented, during the test period, with the first word from each pair. Their task is to recall the word that was paired with it during the study period. Thus, if they were presented with the word boat, the correct response would be hat.  CONCEPTUAL PEG HYPOTHESIS According to this hypothesis, concrete nouns create images that other words can “hang onto.” For example, if presenting the pair boat–hat creates an image of a boat, then presenting the word boat later will bring back the boat image, which provides a number of places on which participants can place the hat in their mind. Dual-code theory : Words with visual cues get both semantic and visual encoding. Paivio (1969) presented words and pictures. Recall in any order or serially. Visual information is superior in its recall-ability than language. Concrete words better remembered than abstract word  MENTAL ROTATION/CHRONOMETRY Roger Shepard and Jacqueline Metzler (1971) inferred cognitive processes by using mental chronometry, determining the amount of time needed to carry out various cognitive tasks. PROCEDURE: subjects saw 2 stimuli and asked to indicate as quickly as possible whether they were the same or different. RESULTS: the time it took to decide if the two objects were the same was directly related to how large the angle of rotation. CONCLUSION: subjects were mentally rotating images to answer the question. Possible that imagery and perception may share the same mechanism.  IMAGE SCANNING AND RESPONSE TIME (KOSSLYN, 1973) AIM: Is imagery, like perception, spatial? PROCEDURE: asked participants to memorize a picture of an object and then create an image of that object in their mind and to focus on one part of the boat, such as the anchor. They were then asked to look for another part of the boat, like the motor, and press True when they found it, or False when they didn’t. RESULTS: Subjects took longer to find parts that were located farther from the initial point of focus because they were scanning the object CONCLUSION: Evidence for the spatial nature of imagery.  Lea (1975) proposed that as subjects scanned, they may have encountered other interesting parts of the boat, and this distracted them and increased reaction time. Kosslyn (1978) responded with a study asking participants to scan between places on a map. He found a linear relationship between reaction time and distance, suggesting participants visual imagery is spatial.  IMAGE SIZE AND RESPONSE TIME (KOSSLYN, 1975, 1976) Moving closer to an object has two effects: 1) the object fills more of our visual field, and 2) details are easier to see. AIM: Does the relationship between viewing distance and the ability to perceive details also occur for mental images? PROCEDURE: Asked participants to imagine a rabbit, either next to an elephant or a fly. In the elephant condition, the elephant fills the visual field, whereas in the fly condition, the rabbit fills the visual field. Subjects were asked, “Does the rabbit have whiskers?” RESULTS: Participants in the ‘fly’ condition answered questions about the detail of the rabbit more quickly because it filled their visual field, was larger. CONCLUSION: Imagery mimics perception in that viewing distance affects ability to perceive details  MENTAL-WALK TASK Imagine walking towards mental image of an animal Estimate how far away when they experience “overflow” Move closer to small animals than large animals Images are spatial, just like perception  THE IMAGERY DEBATE The imagery debate- a debate about whether imagery is based on spatial mechanisms, such as those involved in perception, or on mechanisms related to language, called propositional mechanisms. Kossyln interpreted results of his research as supporting the idea that imagery involves a spatial representation- a representation in which different parts of an image can be described as corresponding to specific locations in space.  Propositional representation: A representation in which relationships are represented by symbols, as when the words of a language represent objects and the relationships between objects. Depictive representation: representations that are like realistic pictures of an object.  Pylyshyn disagreed, saying just because we experience imagery as spatial, doesn’t mean that the underlying representation is spatial. We aren’t always aware of what is going on in our minds. The spatial experience of mental images is an epiphenomenon, something that accompanies the real mechanism but is not actually part of the mechanism.  Tacit-knowledge Explanation - Kosslyn’s results can be explained using real knowledge explanation.  Transcranial magnetic stimulation and visual tasks (Kosslyn et al., 1999) AIM: Respond to criticism by Pylyshyn tht brain activity in response to imagery may indicate that something is happening but may have nothing to do with causing imagery. PROCEDURE: Kossyln presented TMS stimulation to the visual cortex while subjects were carrying out either a perception task or an imagery task. Perception task= subjects viewed a display like 10.17 and were asked to make a judgment about the stripes in two of the quadrants. The imagery condition was asked to do the same, but make the judgments from a mental representation they had of the images.  RESULTS: Stimulation caused subjects to respond more slowly, and that this slowing effect occurred both for perception and for imagery. CONCLUSION: Kosslyn concluded that the brain activation that occurs in response to imagery is not an epiphenomenon and that brain activity in the visual cortex plays a causal role in both perception and imagery  Removing Part of the Visual Cortex Decrease Image Size Patient M.G.S. was a young woman who was about to have part of her right occipital lobe removed as treatment for a severe case of epilepsy. Before the operation, Martha Farah and coworkers (1993) had M.G.S. perform the mental walk task that we described earlier, in which she imagined walking toward an animal and estimated how close she was when the image began to overflow her visual field. This occurred because removing part of the visual cortex reduced the size of her field of view, so the horse filled up the field when she was farther away. This result supports the idea that the visual cortex is important for imagery.  Problems with Perceiving are Accompanied by Problems with Imagery Damage to the parietal lobes can cause a condition called unilateral neglect, in which the 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.  Conclusions From Imagery Debate So, the experiments on manipulating images lead to the same conclusion as all of the other experiments we have described: Imagery and perception have many features in common, but there are also differences between them.  USING IMAGE TO IMPROVE MEMORY Placing Images at Location The power of imagery to improve memory is tied to its ability to create organized locations at which memories for specific items can be placed. Simonides had invented what is now called the method of loci—a method in which things to be remembered are placed at different locations in a mental image of a spatial layout. Placing images at locations can help with retrieving memories later Associating Images with Words The pegword technique involves imagery, as in the method of loci, but instead of visualizing items in different locations, you associate them with concrete words.  INDIVIDUAL DIFFERENCES IN VISUAL IMAGERY Maria Kozhevnikov and coworkers (2005) did an experiment in which they first presented a questionnaire designed to determine participants’ preference for using imagery versus verbal-logical strategies when solving problems. This questionnaire involved solving different kinds of problems and indicating the strategies used to solve these problems. Kozhevnikov classified the participants as visualizers or verbalizers, so this initial result indicated that some people use imagery to solve problems, and some people don’t. We will describe the results of Kozhevnikov’s experiments, focusing on the visualizers.  The visualizers were given tests designed to measure two types of imagery: spatial imagery and object imagery. 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. The paper folding test (PFT) is designed to measure spatial imagery. Participants saw a piece of paper being folded and then pierced by a pencil. Their task was to pick from five choices what the paper would look like when unfolded.  The vividness of visual imagery questionnaire (VVIQ) was designed to measure object imagery. Participants rated, on a 5-point scale, the vivid-ness of mental images they were asked to create. A typical item: “The sun is rising above the horizon into a hazy sky.”  In another experiment, participants were presented with the degraded pictures task and a mental rotation task. The degraded pictures task consisted of a number of degraded line drawings like. The mental rotation task required participants to judge whether pictures like were two views of the same object or mirror-image objects. The answer: Spatial imagers did better in the mental rotation task, and object imagers did better on the degraded pictures task, thus providing more evidence distinguishing between spatial and object imagers References: Goldstein, E. Bruce. (2019). Cognitive Psychology: Connecting Mind, Research and Everyday Experience (5th Edition). Cengage Learning.