Georgia State University ScholarWorks @ Georgia State University Psychology Dissertations Department of Psychology 12-17-2015 An Investigation of Emergent Perceptual Phenomena in Primates: Illusions and Biases in Decision-Making Audrey E. Parrish Georgia State University Follow this and additional works at: https://scholarworks.gsu.edu/psych_diss Recommended Citation Parrish, Audrey E., "An Investigation of Emergent Perceptual Phenomena in Primates: Illusions and Biases in Decision-Making." Dissertation, Georgia State University, 2015. https://scholarworks.gsu.edu/psych_diss/146 This Dissertation is brought to you for free and open access by the Department of Psychology at ScholarWorks @ Georgia State University. It has been accepted for inclusion in Psychology Dissertations by an authorized administrator of ScholarWorks @ Georgia State University. For more information, please contact [email protected]. AN INVESTIGATION OF EMERGENT PERCEPTUAL PHENOMENA IN PRIMATES: ILLUSIONS AND BIASES IN DECISION-MAKING by AUDREY E. PARRISH Under the Direction of Michael J. Beran, PhD, and Sarah F. Brosnan, PhD ABSTRACT The perceptual system operates ideally to reveal rapidly processed, accurate and functional information to an organism. However, illusory phenomena emerge when there is discontinuity between sensory input and perception on the basis of misleading contexts. Because illusions emerge as a byproduct of an otherwise functional and efficient perceptual system, they provide a means to understand better mechanisms of perception within and across species. Beyond anatomical and functional similarities in the visual system across primates, nonhuman primate species reveal intriguing similarities in the perception of visual illusions with one another and humans. This dissertation explored visual illusions across the Order Primates, including human adults and children, chimpanzees, rhesus monkeys, and capuchin monkeys, with a focus on when, why and for whom geometric illusions emerge. Geometric illusions occur when a target’s perceived properties (e.g., size, shape, color) are impacted by an illusory context. Specifically, I focused on similarities and differences in perceptual mechanisms across primate species and on the role of attention in illusion emergence. I also assessed the translational impact of visual illusions on everyday decision-making (i.e., food-choice behavior). Overall, this research demonstrated that illusions are complex, and they emerged differently across species as a function of processing mode (i.e., global versus local processing) and attentional control. Further, not all illusions were perceived equally. External factors including illusory array design (i.e., the relationship between target and inducer stimuli) and testing paradigm directly impacted illusion perception. Response competition emerged if the illusory array was too heavily weighted towards inducing stimuli, such that the inducers were the more salient element within the array relative to the target stimulus. These methodological challenges proved to be especially true for local processors (e.g., monkeys) that first perceived the individual elements within an array prior to perceiving the global figure. The manner in which illusions are presented to pre- and non-verbal species can constrain or perhaps create a scaffold for illusory perception. Comparative research as in this dissertation provides a deeper understanding of how context influences perception and choice and will shed light on how we see and subsequently interact with our world. INDEX WORDS: Perception, Visual illusions, Decision making, Biases, Nonhuman primates, Comparative AN INVESTIGATION OF EMERGENT PERCEPTUAL PHENOMENA IN PRIMATES: ILLUSIONS AND BIASES IN DECISION-MAKING by AUDREY E. PARRISH A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the College of Arts and Sciences Georgia State University 2015 Copyright by Audrey E. Parrish 2015 AN IVESTIGATION OF EMERGENT PERCEPTUAL PHENOMENA IN PRIMATES: ILLUSIONS AND BIASES IN DECISION-MAKING by AUDREY E. PARRISH Committee Chair: Michael J. Beran Sarah F. Brosnan Committee: David A. Washburn Chris M. Conway Electronic Version Approved: Office of Graduate Studies College of Arts and Sciences Georgia State University December 2015 iv DEDICATION I dedicate this dissertation to those who have supported me during this journey, especially my family. To Gio, my loving husband and best friend, I treasure your constant encouragement and support – I could not have done this without you by my side. I also thank my parents, Ellen and Herb, who have always encouraged me to reach for the stars. Your unconditional love and support make it possible to chase my dreams. To my sisters and their families and my grandparents, I am forever grateful for your support, love, and laughter. v ACKNOWLEDGEMENTS To my committee chairs, Michael J. Beran and Sarah F. Brosnan, who have mentored, guided, and supported me throughout my graduate career and the writing of my dissertation. To Mike, I am forever indebted to your mentorship, support, and friendship throughout my time at GSU. You’ve always reminded me that, above all else, science should be fun! To Sarah, thank you for your guidance and for pushing me to be a better scientist! I further thank my committee members, David A. Washburn and Chris M. Conway, and also Charles R. Menzel for your support throughout this dissertation and in my graduate training. I also would like to thank the 2CI Primate Social Cognition, Evolution & Behavior fellowship and the Duane. M. Rumbaugh Fellowship for the generous support of my research. Finally, I thank my fellow graduate students (past and present) and everyone from the Language Research Center, including the primates. vi TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................. v 1 INTRODUCTION .................................................................................................... 14 1.1 Literature Review ............................................................................................... 16 1.1.1 Perception ..................................................................................................... 16 1.1.2 Visual Illusions ............................................................................................. 16 1.1.3 Illusions in Animals ...................................................................................... 21 1.1.4 Ebbinghaus-Titchener Illusion and Delboeuf Illusion ............................... 27 1.1.5 Comparative Variance Explored .................................................................. 33 1.2 Current Aims ...................................................................................................... 43 1.3 Predictions ........................................................................................................... 44 1.4 References ........................................................................................................... 45 1.5 Figures ................................................................................................................. 64 2 PERCEIVING COMPLEXITY: ............................................................................. 69 PERCEPTUAL PROCESSING MODE IN MONKEYS ............................................ 69 2.1 Methods ............................................................................................................... 70 2.1.1 Subjects ......................................................................................................... 70 2.1.2 Apparatus ...................................................................................................... 71 2.1.3 Stimuli ........................................................................................................... 71 2.1.4 Procedure ...................................................................................................... 72 2.2 Results ................................................................................................................. 73 vii 2.2.1 Capuchin Monkeys ....................................................................................... 73 2.2.2 Rhesus Monkeys ........................................................................................... 74 2.3 Discussion ............................................................................................................ 76 2.4 References ........................................................................................................... 80 2.5 Figures ................................................................................................................. 84 3 DO YOU SEE WHAT I SEE? A COMPARATIVE INVESTIGATION OF THE DELBOEUF ILLUSION IN HUMANS (HOMO SAPIENS), RHESUS MONKEYS (MACACA MULATTA), AND CAPUCHIN MONKEYS (CEBUS APELLA) .................................................................................................................... 90 3.1 Experiment 1 ....................................................................................................... 93 3.1.1 Methods ......................................................................................................... 93 3.1.2 Results ......................................................................................................... 100 3.1.3 Discussion ..................................................................................................