PS2111 CDL Lecture 4.pptx

PS2111 Mental Imagery Carlo De Lillo Mental images Imagery Mental representation of things that cannot be currently sensed Can be in any modality Hearing Smell Taste Touch Vision Visual imagery most reported in diary studies (Kosslyn et al 1990) most studied type of imagery in humans How can informa...

PS2111 Mental Imagery Carlo De Lillo Mental images Imagery Mental representation of things that cannot be currently sensed Can be in any modality Hearing Smell Taste Touch Vision Visual imagery most reported in diary studies (Kosslyn et al 1990) most studied type of imagery in humans How can information be represented Symbolic representations e.g. words On (Dog, sofa) “The dog is on the sofa” sematic features abstract knowledge associated with what is represented Analogic representations e.g. pictures spatial features concrete aspects and context of what is represented What are mental images based on Dual code theory (Paivio 1969, 1971) Symbolic code arbitrary symbols such as words used to represent features of objects Analogue code preserves main perceptual features of objects and their transformations as we would observe them by moving in the real world Human use both codes Propositional theory (e.g. Anderson and Bower 1973; Pylyshyn 1973, 1984). Propositions (mentalese) represent deep meaning of objects and their relationship Images, words and statements are all constructed from these deeper propositional representations Functional equivalence hypothesis (e.g. Jolicoeur and Kosslyn 1985; Peterson et al, 1992) Processes for constructing and manipulating mental images are similar to those used in visual perception Mental imagery not identical to perception but functionally equivalent to it What is the colour of the irn-bru label? You probably needed to form a mental image from memory to try to answer this question What are mental images useful for Answer queries and solve problems What is darker red a cherry or an apple? How many windows has the Fielding Johnson building? Make predictions What if questions (Moulton and Kosslyn 2009) Plan actions Cognitive map Map derived from navigating an environment Actively constructed from partial information Tolman (Honzik and Tolman 1930) maze navigation in rats Group A: rewarded to find food box until no errors are made Group B: not rewarded to find food box Group C: Rats not rewarded for 10 trials, then rewarded in 1 trial Group C makes errorless runs in trials following the rewarded one Conclusion: Group C acquired a cognitive map of the environment when freely exploring the maze Mental rotations Shepard and Metzler (1971) Participants decide if pairs of rotated images correspond to the same object Pair of images depict different degrees of rotation RT linearly related to degree of rotation Mental rotation similar to visually observing physical rotation of object Mental images are functionally equivalent to perception Image scaling Kosslyn (1983), in mental images: Details of large object are seen first To see details of small objects we need to zoom in By zooming in loss of information about large objects large object overflow To see whole large objects we need to zoom out again Mental images are like perceptions Operations on mental images resemble what we would see by moving towards or away from physical objects in the real world Image scanning e.g. Kosslyn et al (1978) map memorised until all landmarks can be reproduced in correct position from memory participants asked to travel on imagined map to reach given landmarks press a switch when they get there RT proportional to distance travelled on the map Try to memorise this image Now rotate it in your mind 90 degrees clockwise Did you see this? Are transformations of mental images just as effective as transformations of physical images? Slezak (1991, 1995) asked participants to: memorise one of these images imagine rotating it 90 degrees clockwise report what they saw none of them reported seeing figures that can be seen by rotating this slide mental images do not seem to preserve information as physical images Are mental maps affected by propositions, inferences and conceptual knowledge? Distance estimation from cognitive maps is affected by: density of landmarks in a map (Thorndyke 1981) Cluttered maps judged as larger presence of routes (McNamara et al 1984) Participants asked to decide if cities appeared on previously seen maps If a city is mentioned after one connected by route, participant respond faster Relative position is affected by heuristics Stevens and Coupe (1978) Imagined map of US Is Reno, Nevada, west or east of San Diego, California? Real map Inferred map Gender differences Many studies report a male advantage in mental rotations tests (e.g. Collins and Kimura 1997) Females outperform males in object location memory (Eals and Silverman 1994) Evolutionary interpretations based on foraging specialisation (Eals and Silverman 1994) Hunting: route learning, large scale travelling Gathering: learning sources of food in relation to landmarks Study array Object memory Object location memory Reading Essential Sternberg R.J. Cognitive Psychology (2009), Chapter 7. Knowledge Representation: Images and Propositions. Additional Eysenck, M.W ; Keane, M. T. 2010 Cognitive Psychology: A Student's Handbook, 7th Edition. Chapter 3. Collins, D. W., & Kimura, D. (1997). A large sex difference on a twodimensional mental rotation task. Behavioral Neuroscience, 111(4), 845–849. Eals M. and Silverman, (1994). The Hunter-Gatherer Theory of Spatial Sex Differences: Proximate Factors Mediating the Female Advantage in Recall of Object Arrays. Ethology and Sociobiology 15: 95-105.