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CogPsych ~10
Chapter 10: Visual Imagery
Question | Answer |
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What is visual imagery? | Seeing in the absence of a visual stimulus. |
What is mental imagery? | It is the ability to recreate the sensory world in the absence of physical stimuli. |
What did Wundt state about imagery? | Images were one of the three basic elements of consciousness, along sensations and feelings. He also proposed that because images accompany thought, studying images was a way of studying thinking? |
What is the imageless thought debate? | Some psychologists believe that thought is impossible without an image. Otherwise argued that thinking can occur without images. |
What evidence is there supporting that thinking can occur without images? | Galton (1883) observed that people who had great difficulty forming visual images were still quite capable of thinking. |
What was the behaviourist attitude towards imagery? | They thought the study of imagery unproductive as visual images are invisible to everyone except the person experiencing them. Watson (1928) thought them "unproven" and "mythological" and so unworthy of stuyd. |
How did Alan Paivio's (1963) work on memory link behaviour and cognition? | He showed that it was easier to remember concrete nouns that can be imaged that it is to remember abstract nouns. |
Describe Alan Paivio's (1963) study on memory, which used the paired-associate learning technique. | Subjects were presented with pairs of words during a study period. They were then presented with the first word from each pair, and were tasked to recall the word that was paired with it during the study period. |
What is the conceptual peg hypothesis, as proposed by Paivio (1963)? | Concrete words create images that other words can "hang onto". (e.g. boat-hat - boat image created - provides places for hat to be placed). |
While Paivio inferred cognitive processes by measuring memory, what did Shepard & Metzler (1971) use to infer cognitive processes? | Mental chronometry. |
What is mental chronometry? | Determining the amount of time needed to carry out various cognitive tasks. |
Describe Shepard & Metzler's (1971) experiment using mental chronometry. | They saw pictures of pairs of objects. Their task was to indicate ASAP whether the objects were same/different. They found that the time it took to decide that the two views were of the same object was linearly correlated to how different the angles were. |
What did Shepard & Metzler's (1971) experiment find? | Subjects were mentally rotating one of the views to see whether it matched the other one. |
What was the importance of Shepard & Metzler's (1971) study? | 1. One of the first to apply quantitative methods to the study of imagery 2. and suggest that imagery and perception may share the same mechanisms - the spatial experience for both imagery and perception matches the layout of the actual stimulus. |
What is mental scanning? | Subjects create mental images and then scan them in their minds. |
Describe Kosslyn's (1973) study on imagery using mental scanning. | Subjects memorized a picture of an object (boat) and created an image of that object in their mind and to focus on one part of the boat. They then looked for another part of the boat, and to press the true button when they found this part or false if not |
What did Kosslyn (1973) find in his study? | It took longer for subjects to find parts that are located farther from the initial point of focus because that would be |
What was Lea's (1975) alternative explanation for kosslyn's study? | As subject scanned, they may have ecountered other interesting parts and this distraction may have increased reaction time. |
Describe Kosslyn et al's (1978) scanning experiment. | Subjects scanned an image of an island, and 7 locations. They then formed an image of a black speck moving along a straight line between their location and one of those locations. . Time taken was noted. |
What did Kosslyn et al (1978) discover in their scanning experiment? | They found that it took longer to scan between greater distances on the image, supporting the idea that visual imagery is spatial in nature. |
What is 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? |
What is the difference between Kosslyn and Pylyshyn's interpretations of Kosslyn's research? | The former supported the idea that the mechanism responsible for imagery involved a spatial representation. Pylyshyn, however, argued that just because we experience imagery as spatial doesn't mean that the underlying representation is spatial. |
What is an epipenomenon? | Something that accompanies the real mechanism but is not actually part of the mechanism. |
What did Pylyshyn propose? | Mental images are an epiphenomenon - indicate that something is happening in the mind, but don't tell us how it is happening. He proposed that the mechanism underlying imagery is not spatial but propositional. |
What is a propositional representation? How does it differ from a spatial representation? | Relationships can be represented by abstract symbols e.g. equation/statement. Spatial representations would involve a spatial layout showing objects. ("the cat is under the table" vs cat under table picture) |
What is a depictive representation? | Representations that are like realistic pictures of an object, so that parts of the representation correspond to parts of the object. |
In addition to suggesting that Kosslyn's results can be explained in terms of propositional representations, what else did Pylyshyn propose? | He suggested that scanning time increases with distance as subjects responded to the tasks based on what they know about what usually happens when they are looking at a real scene. (staging a scene) |
What is the tacit knowledge explanation, as proposed by Pylyshyn? | It states that subjects unconsciously use knowledge about the world in making their judgments. |
Describe Finke & Pinker's (1982) study on mental scanning. | Subjects were presented a four dot display and 2 s later an arrow, and indicated whether the arrow was pointing to any of the dots they had just seen. It was found that they took longer to respond for greater distances between the arrow and the dot. |
How did Finke & Pinker's (1982) study on mental scanning counter Pylyshyn's tacit knowledge explanation of Kosslyn's mental scanning results? | Subjects wouldn't have had time to memorize the distances between the arrow and the dot before making their judgments, and so unlikely that they used tacit knowledge about how long it should take to get from one point to another. |
Describe Kosslyn's (1978) study on that the relationship between viewing distance and the ability to perceive details in mental images. | Subjects imagined 2 animals next to each other and they were standing close enough to the larger animal that it filled most of their visual field. He then asked questions like "Does the rabbit have whiskers?" before they found that part and answered ASAP. |
How did Kosslyn's (1978) study demonstrate that the relationship between viewing distance and the ability to perceive details also occurred for mental images? | Subjects answered questions about the rabbit more rapidly when it filled more of the visual field (1.870 vs 2.020 ms). |
What is a mental walk task? | A task in which subjects imagined that they were walking toward a mental image. |
Describe Kosslyn's experiment using the mental walk task. | He asked them to imagine animals. Subjects were to estimate how far away from the animal they were when they began to experience "overflow" (when the image filled the visual field or when its edges started becoming fuzzy). |
What did Kosslyn's mental walk experiment discover? | Subjects had to move closer for small animals (less than 1 foot away from a mouse) than for larger animals (about 11 feet) just as they would have to do if they were walking towards actual animals. |
Describe Parky's (1910) study and results on interaction between perception and imagery. | Subjects mentally projected images of common objects onto a secretly back-projected screen, and then described this image. The descriptions matched the images that Perky was projecting, and none of them were aware that there was an actual picture. |
Describe Farah's (1985) study on perception and imagery. | Subjects imagined either the letter H or the letter T on a screen. They were then flashed two squares, one of which contained a target letter, and they had to guess which square the letter came from. |
What did Farah's (1985) study find? | The target letter was detected more accurately when the subject had been imagining the same letter rather than the different letter. Thus, perception and imagery share mechanisms. |
Why is the propositional approach still not ruled out? | 1. Anderson (1978): still can't rule out the propositional explanation despite evidence 2. Farah (1988): always possible that subjects can still be unknowingly influenced by past experience - difficult to rule out on de basis of behavioural experiments |
What did Farah (1988) suggest as evidence for perception-imagery relationships instead of behavioural experiments? | We should also investigate how the brain responds to visual imagery. Brain imaging experiments provided additional data regarding the physiology of imagery. |
Describe Kreiman et al's (2000) study on the physiology of imagery. | He found neurons that responded to some objects but not to others, and that these neurons fired in the same way when the person imagined the object. He called them "imagery neurons". |
How did Bihan et al's (1993) study showed that both perception and imagery activate the imagery cortex? | Activity in the striate cortex increased both when a person observed stimuli and imagined the same stimuli. In addition, asking subjects to think about imagery questions generated a greater response in the striate cortex than non-imagery questions. |
How does the size of the object affect activation in the visual cortex? | Perceiving small objects causes activity in the back of the visual cortex, and looking at larger objects causes activity to spread toward the front of the visual cortex. |
Described Kosslyn's (1995) study on imagery and activation. | Subjects created small, medium and large visual images in a scanner. Small visual images caused activity at the back of the brain, but increases in size brought the activity forward to the front just as it does for perception. |