Topics in acoustics, production and perception of psittacine speech Item Type text; Dissertation-Reproduction (electronic) Authors Patterson, Dianne Karen, 1961- Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 07/10/2021 04:12:32 Link to Item http://hdl.handle.net/10150/282871 INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UME films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. 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UMI 300 North Zeeb Road Ann Arbor, MI 48103 2 THE UNIVERSITY OF ARIZONA ® GRADUATE COLLEGE As members of the Final Examination Conimittee, we certify that we have read the dissertation prepared by D"i^nne Patterson entitled TOPICS in AROU';TIR';. Prndiirl-inn snd Pprrpntinn of Ps'ittacinp Soepch and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Rnrtnr nf Phi1n<;nnhy Date Dr. Date Dr. Demer Date [ 9- Dr. Date Dr.Chiasson Da Final approval and acceptance of this dissertation is contingent upon the candidate's submission of the final copy of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. Diss^rtatiofi Direct Pepperberg Date 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the copyright holder. 4 ACKNOWLEDGEMENTS My thesis advisor. Dr. Irene Pepperberg spent hours, perhaps years of her time trying to teach me to write and think. After my early drafts, we always worked closely on the writing, rewriting, and editing. She suggested statistical tests and avenues of research that did not occur to me. She carefully (and frequently) reviewed my work and caught logical flaws and inadequacies. I cannot thank her enough. Every aspect of this dissertation has benefitted from the comments and suggestions of my committee members: Dr. Pepperberg, Dr. Green, Dr. Chiasson, Dr. Demers, and Dr. Qi. Special thanks also go to my son, who had to put up with my obsessive writing and to Tom Hicks for his caring, support, programming and editing. 5 DEDICAHON In fond memory of Dr. Kerry Green 6 TABLE OF CONTENTS ABSTRACT 8 L INTRODUCTION 10 THE PROBLEM AND ITS CONTEXT 10 LITERATURE REVIEW 11 THESIS FORMAT 19 N. PRESENT STUDY 22 ACOUSTIC STUDIES 22 ARTICULATION STUDIES 26 PERCEPTION STUDY 29 SUMMARY 31 REFERENCES 32 APPENDIX A: A COMPARATIVE STUDY OF HUMAN AND PARROT PRONATION: ACOUSTIC AND ARTICULATORY CORRELATES OF VOWELS 38 APPENDIX B: ACOUSTIC AND ARTICULATORY CORRELATES OF STOP CONSONANTS IN A PARROT AND A HUMAN SUBJECT 56 APPENDIX C: MECHANISMS OF AMERICAN ENGLISH VOWEL PRODUCTION IN A GREY PARROT {PSUTACUS ERITHACUS) 78 7 TABLE OF CONTENTS—Continued APPENDIX D: HOW PARROTS TALK: INSIGHTS BASED ON CT SCANS, IMAGE PROCESSING AND MATHEMATICAL MODELS 99 APPENDIX E: NORMALIZATION AND CATEGORIZATION PROCESSES: ADAPTING TO A SINGLE EXCEPTIONAL SPEAKER OVER TIME 169 8 ABSTRACT By examining psittacine speech (primarily from a Grey parrot, Psittacus erithacus, named Alex) in a series of two acoustic studies, two articulatory studies and one perceptual study, this dissertation demonstrates that some aspects of human language are not unique to our species. The first two studies identify frequency, intensity and durational aspects of, respectively, Alex's vowels (/i,I,e,e,£,D,a,o,U,u/) and stop consonants (/p,b,t,d,k,g/) that either differ from or resemble their human coimterparts (primarily I. M. Pepperberg). Our results indicate that Alex produces acoustically distinct phonemes using more high frequency information than do humans. In both studies, we use acoustic data to make predictions about articulation. We also compare Alex's speech to that of a mynah, and conclude that these species use different mechanisms to produce speech. The third and fourth study examine vowel articulation: The third study, an. X-ray videotape analysis, establishes that Alex configures his vocal tract in distinct ways for /i/ and /D/. The fourth study models more than 2800 Grey parrot vocal tract shapes as conjoined mbes with known area fimctions and calculates associated vowel formants. The relationship between these mathematical models and formant values for /i,I,e,s,se,D,0,o,U,u/ is consistent with findiags from the vowel study. X-ray study, Grese's unpubl. data and personal observations of relationships between Alex's vocal tract configurations and vowel production. The third and fourth studies show that Alex's "phonemes" are articulatorily distinct. The fifth study is perceptual and examines the relationship between acoustic characteristics of psittacine vowels and the accuracy with which 9 listeners perceive them. We find evidence that Alex's acoustically least "human" vowel, /i/, is very difficult for listeners to perceive unless they have substantial exposure to Alex (on the order of several months). More acoustically prototypical vowels, like foL are accurately identified even by less experienced listeners. We thus find that, at least for experienced listeners, Alex's "phonemes" are perceptually distinct. In sum, the dissertation provides acoustic, articulatory and perceptual evidence of phonemes and other phonetic structure in the speech of a psittacid. 10 1. INTRODUCTION The Problem and its Context My dissertation challenges the claim that certain properties of language are unique to humans. Lieberrtian (1996), for example, proposed that voluntary control of portions of the upper vocal tract for linguistic ends is uniquely human. Few researchers explore the possibility that such supposedly unique abihties might be manifested in a nonhuman subject. My dissertation, however, provides evidence that a Grey parrot (Psittacus erithacus) can learn voluntary control of portions of its upper vocal tract for linguistic ends, and describes a variety of phonetic phenomena in psittacine speech that have never been described in nonhumans. More specifically, I show that Grey parrot speech can be analyzed into acoustically, articulatorily and perceptually distinct sounds or "phonemes", and that contrary to findings for most birds, vocal tract resonances largely accoimt for the characteristics of these sounds. I focused my work on one Grey parrot, Alex, who has a referential vocabulary of over 100 words. Alex is an optimal subject for work on speech production and phonemes for three reasons: First, Alex produces copious speech. A large body of taped data is thus available for analysis and specific utterances can be elicited, with relative ease. Second, Alex has several referential minimal word pairs (e.g., "pea" /pi/ and "key" /ki/). The presence of these minimal word pairs is crucial for establishing the existence of phoneme-like contrasts (e.g., /p/ versus /k/) for the bird. Third, Alex engages in soHtary sound play during which he recombines elements to form novel utterances. This sound play suggests that Alex parses words into syllabic and subsyllabic elements and treats II speech sounds as interchangeable only if they belong to the same natural class (e.g., obstruents only substitute for other obstruents, never for vowels). Prompted by these data, I examined acoustic, articulatory and perceptual evidence of structure in Alex's speech. During the course of my research, questions regarding the mechanisms of avian sound production surfaced.