Contextual Variation in Contextual Variation in Chimpanzee Pant Hoots and its Chimpanzee Pant Hoots and its

Implications for Referential Implications for Referential CommunicationCommunication

Hugh NotmanHugh Notman¹¹

Biological AnthropologyBiological Anthropology

Athabasca UniversityAthabasca University

Drew RendallDrew Rendall²²

Department of PsychologyDepartment of Psychology

University of LethbridgeUniversity of Lethbridge

The “referential” paradigmThe “referential” paradigm

Call structure is Call structure is arbitrary with respect arbitrary with respect to referentto referent

Receivers attending to Receivers attending to acoustic structure for acoustic structure for cues to context cues to context

Information-transfer Information-transfer functionfunction

““Semantic” utterances? Semantic” utterances?

Photo: Cheney & Seyfarth

Photo: Roger Fouts “Next of Kin”

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1. Referential Model1. Referential Model

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2. Syntactical Model2. Syntactical Model

Shortcomings of referential Shortcomings of referential and syntax modelsand syntax models

Assumes caller and receiver attend to the Assumes caller and receiver attend to the same referent(s)same referent(s)

Syntax model ignores function of calls used Syntax model ignores function of calls used singularlysingularly

Problems assigning context to calls: Problems assigning context to calls: assumes static link between call and assumes static link between call and contextcontext

Notman and Rendall 2005 Notman and Rendall 2005 . . Animal Behaviour, Animal Behaviour, 7070, 177-, 177-

190.190. Analyzed chimpanzee pant hoots Analyzed chimpanzee pant hoots

from Budongo forest, Ugandafrom Budongo forest, Uganda 201 calls from 7 males201 calls from 7 males

INDIVIDUAL INDIVIDUAL MALEMALE

AGE CLASSAGE CLASS NUMBER OF NUMBER OF CALLSCALLS

JmJm AdultAdult 3131

MuMu AdultAdult 3636

DnDn AdultAdult 3030

BkBk AdultAdult 3333

NkNk Young adultYoung adult 2525

ZfZf Young adultYoung adult 3030

MaMa AdultAdult 1616

TOTALTOTAL 201201

Pant HootsPant Hoots

Results summaryResults summary

Most salient variation in chimpanzee Most salient variation in chimpanzee pant hoots is between pant hoots is between individualsindividuals, , not contextsnot contexts..

Pant hoots show structural Pant hoots show structural differences between “travel” and differences between “travel” and “non-travel” contexts“non-travel” contexts

Results summaryResults summary

Most salient variation in chimpanzee Most salient variation in chimpanzee pant hoots is between pant hoots is between individualsindividuals, , not contexts.not contexts.

Pant hoots show structural Pant hoots show structural differences between “travel” and differences between “travel” and “non-travel” contexts“non-travel” contexts

Travel Arrive at food Rest

““Travel” Pant Hoot (ground)Travel” Pant Hoot (ground)

Resting (tree)Resting (tree)

Subtle structural differences evident Subtle structural differences evident between some contexts reflect different between some contexts reflect different effects on vocal production introduced by effects on vocal production introduced by variable arousal and the physical demands variable arousal and the physical demands on vocal effort associated with calling in on vocal effort associated with calling in those contexts.those contexts.

This, in part, dependent on elevation of caller, This, in part, dependent on elevation of caller, social circumstance (arriving at food, looking to social circumstance (arriving at food, looking to join others, etc) and physical activity join others, etc) and physical activity (running/walking/resting) of caller.(running/walking/resting) of caller.

Ie., source of variation Ie., source of variation incidentalincidental to caller to caller activityactivity

3. “Embedded context” 3. “Embedded context” modelmodel

Ground vs. treeLocation in range Knowledge of area resourcesDirection of travel (if >1 call)Current social relationship

Implications for referential Implications for referential communicationcommunication

Any referential function for pant hoots likely Any referential function for pant hoots likely based in mechanisms involved in the based in mechanisms involved in the inferential abilities on the part of listeners inferential abilities on the part of listeners

NOT mechanisms underlying the production NOT mechanisms underlying the production of referential contrasts in callers of referential contrasts in callers

This “production/comprehension” This “production/comprehension” asymmetry also evident in signaling asymmetry also evident in signaling systems of other animals AND in language systems of other animals AND in language trained apes.trained apes.

Advantages of embedded Advantages of embedded context modelcontext model

Helps explain lack of contextual specificity Helps explain lack of contextual specificity (as well as inconsistent receiver response) (as well as inconsistent receiver response) to specific call types to specific call types

A more “holistic” approach to A more “holistic” approach to understanding communication (involves understanding communication (involves dimensions associated with acoustic dimensions associated with acoustic structure, receiver perception and structure, receiver perception and cognition as it relates to prior knowledge cognition as it relates to prior knowledge and experience).and experience).

Implications for language…?Implications for language…?

AcknowledgementsAcknowledgements

Natural Sciences and Engineering Natural Sciences and Engineering Research Council of Canada (NSERC)Research Council of Canada (NSERC)

University of CalgaryUniversity of Calgary Calgary ZooCalgary Zoo The Budongo Forest ProjectThe Budongo Forest Project Drew Rendall; Mary Pavelka; Vernon Drew Rendall; Mary Pavelka; Vernon

Reynolds; John Vokey. Reynolds; John Vokey.