Evidence for Human-Like Conversational Strategies in An
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EVIDENCE FOR HUMAN-LIKE CONVERSATIONAL STRATEGIES IN AN AFRICAN GREY PARROT'S SPEECH by ERIN NATANNIE COLBERT-WHITE (Under the Direction of Dorothy Fragaszy) ABSTRACT Researchers have established many similarities in the structure and function of human and avian communication systems. This dissertation investigated one unique nonhuman communication system—that of a speech-using African Grey parrot. In the same way that humans learn communicative competence (i.e., knowing what to say and how given a particular social context), I hypothesized that Cosmo the parrot‘s vocalizations to her caregiver, BJ, would show evidence of similar learning. The first study assessed turn-taking and the thematic nature of Cosmo‘s conversations with BJ. Results confirmed that Cosmo took turns during conversations which were very similar to humans‘ average turn-taking time. She also maintained thematically linked dialogues, indicating strategic use of her vocal units. The second study investigated Cosmo‘s ability to take BJ‘s auditory perspective by manipulating the distance between the two speakers. As predicted, Cosmo vocalized significantly more loudly when her owner was out of the room, and those vocalizations classified as social (e.g., kiss sounds) were uttered significantly more loudly than vocalizations which were considered nonsocial (e.g., answering machine beep sounds). These results suggested Cosmo may be able to take the perspective of a social partner, an ability others have documented in Greys using alternative tasks. Strategic use of vocalizations was revisited in Studies 3 and 4. The third study examined Cosmo‘s requesting behavior by comparing three separate corpora (i.e., bodies of text): Cosmo‘s normal vocalizations to BJ without requesting, Cosmo‘s vocalizations following a denied request, and Cosmo‘s vocalizations following an ignored request. Cosmo treated all three speech contexts differently; distributions and rate of use of speech, nonspeech, social, and nonsocial vocalizations differed significantly. The results of the fourth study supported the third study‘s findings. While Cosmo did not use phrases which BJ classified as ―jokes‖ significantly more often following a refused request (which would indicate strategic use of vocalizations to manipulate affect), her vocalization patterns indicated that she perceived the refusal condition as being different from normal conversation. While the results can be compared to child sociocognitive development, my findings may also be extended to wild Greys‘ communication system to learn more about the species‘ natural capabilities. INDEX WORDS: African Grey parrot, language, communication, turn-taking, communicative competence, perspective-taking, requesting, humor EVIDENCE FOR HUMAN-LIKE CONVERSATIONAL STRATEGIES IN AN AFRICAN GREY PARROT'S SPEECH by ERIN NATANNIE COLBERT-WHITE BS, Denison University, 2007 MS, University of Georgia, 2009 A Dissertation Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY ATHENS, GEORGIA 2013 © 2013 Erin Natannie Colbert-White All Rights Reserved EVIDENCE FOR HUMAN-LIKE CONVERSATIONAL STRATEGIES IN AN AFRICAN GREY PARROT'S SPEECH by ERIN NATANNIE COLBERT-WHITE Major Professor: Dorothy Fragaszy Committee: Gary Baker Michael Covington Adam Goodie Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia May 2013 DEDICATION I dedicate this dissertation to Betty Jean Craige and Cosmo. Without them, my graduate career would have been far less exciting. iv ACKNOWLEDGEMENTS To my adviser Dr. Dorothy Fragaszy, I say thank you for your patience and support. To committee members Drs. Michael Covington, Adam Goodie and Gary Baker, I appreciate your thoughtful input throughout the process, and great conversations along the way. I thank my family, friends, and mentors who supported me throughout the years. In addition, I offer special thanks to Hannah Hall, Marisol Macias, and Rachel Callery for their help with data collection and organization, as well as Dominic Byrd for his artistic ability and encouragement. Thank you to Michael Amlung, Sarah Whitaker, and (especially!) Vijay Veeraghattam for second-semester writing motivation. I also thank the University of Georgia State Botanical Gardens for existing. The gardens helped me get over my brief battle with senioritis in January 2013. I learned that giant banana leaves and papaya trees are an inspirational and motivational force. Above all, I thank both Betty Jean Craige and Cosmo for their participation and excitement, along with Betty Jean‘s continued support and confidence in me to show the world just how phenomenal Cosmo is! v TABLE OF CONTENTS Page ACKNOWLEDGEMENTS .................................................................................................v LIST OF TABLES ........................................................................................................... viii LIST OF FIGURES .............................................................................................................x CHAPTER 1 INTRODUCTION AND LITERATURE REVIEW .........................................1 LANGUAGE IN ACTION ..........................................................................1 NONHUMAN LANGUAGE RESEARCH .................................................3 2 STUDY #1: TURN-TAKING AND DIALOGUE ..........................................14 INTRODUCTION .....................................................................................16 METHOD ..................................................................................................19 RESULTS ..................................................................................................22 DISCUSSION ............................................................................................26 3 STUDY #2: PERCEPTUAL PERSPECTIVE-TAKING ................................57 INTRODUCTION .....................................................................................59 METHOD ..................................................................................................64 RESULTS ..................................................................................................67 DISCUSSION ............................................................................................71 4 STUDY #3: DENIED AND IGNORED REQUESTS ....................................91 INTRODUCTION .....................................................................................93 vi METHOD ..................................................................................................98 RESULTS ................................................................................................101 DISCUSSION ..........................................................................................106 5 STUDY #4: MANIPULATING AFFECT THROUGH ―JOKES‖ ...............136 INTRODUCTION ...................................................................................138 METHOD ................................................................................................141 RESULTS ................................................................................................145 DISCUSSION ..........................................................................................147 6 GENERAL CONCLUSIONS ........................................................................170 SUMMARY OF FINDINGS FROM PRESENT STUDY ......................171 THE ROLE OF ECOLOGICAL RELEVANCE .....................................176 FUTURE DIRECTIONS .........................................................................179 CONCLUSIONS......................................................................................180 vii LIST OF TABLES Page Table 2.1: Nonword sound coding scheme ........................................................................36 Table 2.2: Length, turn, interruption, and theme data for each conversation ....................38 Table 2.3: Conversation initiations made by Betty Jean....................................................48 Table 2.4: Single and multiple turns within turns ..............................................................49 Table 2.5: Longest single-turn turn-taking event ...............................................................50 Table 2.6: Common themes in dialogues and their respective frequencies .......................51 Table 3.1: Nonword sound coding scheme ........................................................................83 Table 3.2: Social and nonsocial vocalization classification ...............................................85 Table 3.3: Volume (dB) of vocalizations for classifications and social contexts ..............88 Table 4.1: Nonword sound coding scheme ......................................................................117 Table 4.2: Social and nonsocial vocalization classification .............................................119 Table 4.3: Twenty most frequently uttered vocalizations and respective frequencies ....122 Table 4.4: Conversation excerpts containing repetition and redirection .........................123 Table 4.5: Conversation excerpts containing interruption ...............................................125 Table 4.6: Conversation except containing a denied then met request ............................127 Table 4.7: Conversation excerpts containing persistence and refocusing .......................129 Table 4.8: Conversation excerpt containing