Chimpanzees differentially produce novel vocalizations to capture the attention of a human

Abstract

Chimpanzees produce numerous species-atypical signals when raised in captivity. Here we report contextual elements of the use of two captivity-specific vocal signals, the "raspberry" and the extended grunt. Results demonstrate that these vocalizations are not elicited by the presence of food; rather the data suggest that these vocalizations function as attention-getting signals. These findings demonstrate a heretofore underappreciated category of animal signals: novel signals invented in novel environmental circumstances. The invention and use of species-atypical signals, considered in relation to group differences in signaling repertoires in apes in their natural habitats, may index a generative capacity in these hominoid species without obvious corollary in other primate species.A heretofore little-studied, yet theoretically important class of animal signals are those produced uniquely within some, but not other populations of the same species. Nowak, Plotkin, and Jansen (2000) listed three putatively exhaustive categories of animal communication designs: "a finite repertoire of calls … ; a continuous analogue signal … ; and series of random variations on a theme" (p. 495). Clearly, the class of novel signals developed by animals is missing from that list. The number of such signals in both the auditory and visual domains is growing rapidly, with recent empirical research into the communicative repertoires of both captive and wild chimpanzees. Wild chimpanzees exhibit a number of group differences in their communicative repertoires, including parametric-as opposed to qualitativedifferences in their vocal repertoires (e.g., Crockford, Herbinger, Vigilant, & Boesch 2004), and qualitative differences in their visual signals, including patchy distribution of the leafclipping display (Nishida, 1980) Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Hostetter et al. 2001; Krause & Fouts 1997;Leavens et al. 2004a;Tomasello, Call, Nagell, Olguin, & Carpenter 1994). In these studies, food is typically placed outside the focal subject's home cage and is therefore out of reach from the subject. In these circumstances, chimpanzees and other great apes only gesture to the food when a human is present and visually oriented toward the subject Hostetter et al. 2001; Krause & Fouts 1997;Leavens, Hopkins, & Bard 1996;Leavens, Hopkins, & Thomas 2004b;Tomasello et al. 1994). Moreover, chimpanzees alternate their gaze between the referent (food) and the social agent while gesturing (Leavens & Hopkins 1998) and "repair" their gestural communication when it has failed (Leavens et al. ...

Learned vocal and breathing behavior in an enculturated gorilla

“…Several studies of captive chimpanzees (described above) reported their use of novel vocalizations and nonvocal sounds as voluntarily controlled attention getters with human interactants (Hopkins, et al 2007;Leavens et al 2004Leavens et al , 2010. These learned sounds included an unvoiced raspberry and also a voiced extended grunt, described as a low, loud, guttural sound made with the mouth open (also see Krauss and Fouts 1997, which noted the use of a raspberry as an attention getter by a sign-taught chimpanzee).…”

“…A set of studies found that captive chimpanzees housed at the Yerkes National Primate Research Center were more likely to use manual gestures to communicate with a visually attentive experimenter, but were more inclined to produce vocalizations and non-vocal sounds when the experimenter was inattentive or facing away (Hopkins et al 2007;Leavens et al 2004Leavens et al , 2010. For example, chimpanzees tactically employed vocalizations in the service of gaining the attention of an inattentive human interlocutor with access to food.…”

“…As evidence suggests that multiple modalities function together interdependently in modern language, a plausible hypothesis for its evolution is that multiple modalities also evolved together interdependently (Kendon 2009;McNeill 2012). Some ape gesture researchers are similarly coming to the conclusion that the evolution of language is best understood from a multimodal perspective (Hopkins et al 2007;Leavens 2003;Taglialatela et al 2011;Waller et al 2013). For example, Leavens (2003) proposed that, ''Because visual and vocal communication seem to be functionally linked in extant apes, language may have been multimodal from its inception'' (p. 233).…”

Where Apes and Songbirds are Left Behind: A Comparative Assessment of the Requisites for Speech

“…Nonhuman primates do show some modification of vocal output, but this seems to be based largely on modification of innate calls through altering positioning of the mouth or lips rather than through control of the larynx. For instance, chimpanzees can produce novel sounds to attract attention by puckering and vibrating their lips to create a "raspberry" sound (Hopkins, Taglialatela, & Leavens, 2007), and captive orangutans (Pongo pygmaeus) have spontaneously matched human whistles (Lameira et al, 2013). In contrast, in humans there is precise control of voicing itself, allowing for a far wider repertoire of different learned patterns.…”

Considering the role of social dynamics and positional behavior in gestural communication research

“…However, aside from a report of a captive orangutan imitating a human whistle without explicit training [Wich et al, 2008], there is no evidence that non-human primates invent new vocalizations without extensive human contact or human enculturation. Additionally, there is only limited evidence of flexible call production or usage outside of fixed social contexts [Hopkins et al, 2007;Janik & Slater, 2000;Marshall et al, 1999;Mitani & Brandt, 1994;Ouattara et al, 2009a;Seyfarth & Cheney, 1997;Seyfarth et al, 1980;Snowdon & Hodun, 1981;Tomasello & Zuberbühler, 2002]. Creating new signals and using them in multiple contexts are key aspects of human language, yet these phenomena are not pervasive in non-human primate vocal communication.…”