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Proquest Dissertations Examining the Role of Object Size in Judgments of Lateral Separation by Robert H. Thomson A thesis submitted to the Faculty of Graduate and Postdoctoral Affairs in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Cognitive Science Carleton University Ottawa, Ontario ©2011 Robert H. Thomson Library and Archives Bibliotheque et 1*1 Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington OttawaONK1A0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-81556-4 Our file Notre r6f6rence ISBN: 978-0-494-81556-4 NOTICE: AVIS: The author has granted a non­ L'auteur a accorde une licence non exclusive exclusive license allowing Library and permettant a la Bibliotheque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'lnternet, preter, telecommunication or on the Internet, distribuer et vendre des theses partout dans le loan, distribute and sell theses monde, a des fins commerciales ou autres, sur worldwide, for commercial or non­ support microforme, papier, electronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in this et des droits moraux qui protege cette these. Ni thesis. Neither the thesis nor la these ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent etre imprimes ou autrement printed or otherwise reproduced reproduits sans son autorisation. without the author's permission. In compliance with the Canadian Conformement a la loi canadienne sur la Privacy Act some supporting forms protection de la vie privee, quelques may have been removed from this formulaires secondaires ont ete enleves de thesis. cette these. While these forms may be included Bien que ces formulaires aient inclus dans in the document page count, their la pagination, il n'y aura aucun contenu removal does not represent any loss manquant. of content from the thesis. 1+1 Canada ii ABSTRACT The goal of the present research was to examine the influence of object size on judgments of lateral separation using a one-shot change detection paradigm. Prior research on judgments of separation (e.g., Levin & Haber, 1993) argued that visual angle is the predominant determiner of judgments of depth and separation (i.e., exocentnc distance). Gogel and Da Silva (1987a) proposed a two-process theory to explain depth judgments. This theory states that both perceptual (e.g., visual angle) and cognitive factors (e.g., familiar size) influence people's ability to judge the distance to an object. The present research consists of four experiments which extended the investigation of size cues to judgments of lateral separation and evaluated their consistency with Gogel's theory of off-sized perceptions. Experiments 1 and 3 used a forced-choice response, finding a significant influence of object size on distance judgments. Participants accurately detected changes in linear separation. Concurrent changes in object size, however, significantly reduced the accuracy of distance judgments. Moreover, pattern mask duration was varied and two interference conditions were included in Experiment 3. Longer mask durations appeared to exacerbate a trend to underestimate distances and the effectiveness of size cues was somewhat reduced by the interference task. These results are compatible with the view that size cues typically influence a secondary, cognitive stage of processing whose effect is diminished due to competition for resources with the interference task. Experiments 2 and 4 replicated the results of Experiments 1 and 3 using a distance reproduction task. In Experiment 2, participants dragged the mouse to reproduce a distance given in a source image from memory. Similar to the forced-choice results of Experiments 1 and 3, changing object size was reflected in a linear change in distance iii reproductions. In Experiment 4, participants both estimated line lengths using a given square as a metric (line estimates) and produced lines of n square-lengths (line production). The results of Experiment 4 provided converging evidence that object size influences judgments of lateral separation regardless of response type. In summary, the present research identifies that object size is a significant determiner of judgments of lateral separation consistent with the predictions of Gogel's Theory of Off-sized Perceptions. IV ACKNOWLEDGEMENTS I would like to thank Dr. Aryn Pyke for her encouragement during the formulation of the topic and experiments. Without her support and understanding I would not have been able complete this project. I would also like to thank Dr. Guy Lacroix for taking a chance and accepting me as a student, when at the time I had no dissertation topic and little research experience. Whether listening through dozens of brainstorming sessions or reading the document over and over, I always had someone pushing me forward. I would also like to thank Dr. Rob West and Dr. Jim Davies for donating extra lab space which allowed me to dedicate myself to full-time data collection and analyses during the home stretch. Finally, I would like to thank my parents George and Paula Thomson, who taught me to work to the best of my ability and follow through, even when a problem seems insurmountable. V TABLE OF CONTENTS Abstract ii Acknowledgements iv Table of Contents v List of Figures viii List of Tables xi Introduction 1 Terminological Conventions 5 The Size-Distance Invariance Hypothesis 6 Limitations and Modifications of the Classical SDIH 8 The Role of Task Instructions on Size and Distance Judgments 8 The Role of Visual Illusions and the Size-Distance Paradox 12 The Moon Illusion 13 The Ebbinghaus Illusion 15 The Muller-Lyer Illusion 18 Visual illusions: Dissociating Perception and Prior Knowledge 20 The Role of Size and Distance Cues on Depth Perception 22 Distance Cues 22 The Equidistance Tendency 24 The Specific Distance Tendency 25 The Role of Distance Cues in Size and Depth Constancy 27 Direct Reports of the Familiar Size Cue 29 Indirect Reports of the Familiar Size Cue 34 The Theory of Off-Sized Perceptions 36 Limitations of the Theory of Off-Sized Perceptions 42 The Incompleteness of Dual-Process Models 43 Extending the Theory of Off-Sized Perceptions 48 Investigative Approach 54 The One-Shot Change Detection Methodology 56 Extending the Change Detection Paradigm 58 VI Hypotheses 62 Summary 66 General Method 68 Materials 68 Apparatus 68 Stimuli 69 Procedure 71 Experiment 1 74 Method 77 Participants 77 Materials 77 Procedure 77 Results 79 Accuracy 80 Response Latencies 83 Patterns of Errors 86 Discussion 88 Experiment 2 99 Method 101 Participants 101 Materials 101 Procedure 102 Results 103 Accuracy 104 Response Latencies 106 Patterns of Errors 108 Discussion 110 Experiment 3 117 Method 119 Participants 119 Materials 119 vii Procedure 120 Results 122 Accuracy 123 Response Latencies 129 Patterns of Errors 132 Discussion 134 Experiment 4 140 Method 143 Participants 143 Materials 143 Procedure 143 Results 145 Line Production Task 145 Line Magnitude Estimation Task 149 Discussion 152 General Discussion 157 Summary of Experiments 158 Implications of Off-Sized Perceptions in Exocentric Distances 160 The Anisotropy of Visual Space 163 Re-Examining the Evidence for Dual-Process Models 165 The Role of Object Size in the Mapping of Visual Space 166 Original Contributions of the Change Detection Task 171 Future Work 172 Summary 176 References 180 Appendix A: List of Descriptive Statistics 197 Appendix B: Experiment 3 Interference Condition Stimuli 214 Vlll LIST OF FIGURES Figure 1. The moon illusion. No matter the moon's location in the sky, the distance between an observer and the actual path of the moon remains relatively constant. Nonetheless, observers perceive the moon to become smaller as it approaches its zenith 13 Figure 2. The Ebbinghaus illusion. The Ebbinghaus illusion is created when two target circles of identical sizes, one flanked by smaller circles and the other flanked by larger circles are presented side by side. This stimulus arrangement generates the illusion that the target circles are of different sizes 16 Figure 3. Two examples of the Muller-Lyer illusion. In the traditional Muller-Lyer image (on the left), the orientation of the arrowheads affects the perception of the length of the lines. In the variant on the right, the arrowheads are replaced by squares. The lower line is perceived shorter even though it is the same length as the upper line. 18 Figure 4. An example of a convex (left) and concave (right) simulated 3D corner. Due to perspective size constancy, it is theorized that the left image is longer because the line is apparently farther in depth in the convex corner than the concave corner 19 Figure 5. Sample process model minimally required to account for the predictions of the theory of off-sized perceptions 46 Figure 6. Illustrations showing how exocentric distance perception may be similar to size perception. In both examples, an observer is making a judgment based on visual angle and relative depth to a target. The difference is that for exocentric perceptions the target is empty space (the inter-object distance), while for perceived size the target is the object 53 Figure 7. Perspective acts as a size cue. This use of perspective is considered an unconscious inference outside the domain of psychophysics. Image reproduced from "The Motion Aftereffect" (1998, p.505). Mather, G. Verstraten F., Anstis, S. (eds). MIT 60 Figure 8. An example of how relative size cue can affect distance perception. Despite the inter-object distance being the same between the source and target images, the relative size of the distance is four objects in the source image and three objects in IX the target image.
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