Primate Vocal Communication and the Evolution of Speech

2021 ◽  
Vol 30 (1) ◽  
pp. 55-60
Author(s):  
Julia Fischer

Studies of nonhuman primate communication are often motivated by the desire to shed light on the evolution of speech. In contrast to human speech, the vocal repertoires of nonhuman primates are evolutionarily highly conserved. Within species-specific constraints, calls may vary in relation to the internal state of the caller or social experience. Receivers can use signalers’ calls to predict upcoming events or behavioral dispositions. Yet nonhuman primates do not appear to express or comprehend communicative or informative intent. Signalers are sensitive to the relation between their own actions and receivers’ responses, and thus, signaling behavior can be conceived as goal directed. Receivers’ ability to integrate information from multiple sources renders the system flexible and powerful. Researchers who take a linguistic or biological perspective on nonhuman primate communication should be aware of the strengths and limitations of their approaches. Both benefit from a focus on the mechanisms that underpin signaling and responses to signals.

2019 ◽  
Vol 375 (1789) ◽  
pp. 20190045 ◽  
Author(s):  
Julia Fischer ◽  
Kurt Hammerschmidt

The extent to which vocal learning can be found in nonhuman primates is key to reconstructing the evolution of speech. Regarding the adjustment of vocal output in relation to auditory experience (vocal production learning in the narrow sense), effects on the ontogenetic trajectory of vocal development as well as adjustment to group-specific call features have been found. Yet, a comparison of the vocalizations of different primate genera revealed striking similarities in the structure of calls and repertoires in different species of the same genus, indicating that the structure of nonhuman primate vocalizations is highly conserved. Thus, modifications in relation to experience only appear to be possible within relatively tight species-specific constraints. By contrast, comprehension learning may be extremely rapid and open-ended. In conjunction, these findings corroborate the idea of an ancestral independence of vocal production and auditory comprehension learning. To overcome the futile debate about whether or not vocal production learning can be found in nonhuman primates, we suggest putting the focus on the different mechanisms that may mediate the adjustment of vocal output in response to experience; these mechanisms may include auditory facilitation and learning from success. This article is part of the theme issue ‘What can animal communication teach us about human language?’


2021 ◽  
Vol 7 (14) ◽  
pp. eabg0677
Author(s):  
Becca Franks ◽  
Christopher Ewell ◽  
Jennifer Jacquet

The unprecedented growth of aquaculture involves well-documented environmental and public-health costs, but less is understood about global animal welfare risks. Integrating data from multiple sources, we estimated the taxonomic diversity of farmed aquatic animals, the number of individuals killed annually, and the species-specific welfare knowledge (absence of which indicates extreme risk). In 2018, FAO reported 82.12 million metric tons of farmed aquatic animals from six phyla and at least 408 species—20 times the number of species of farmed terrestrial animals. The farmed aquatic animal tonnage represents 250 to 408 billion individuals, of which 59 to 129 billion are vertebrates (e.g., carps, salmonids). Specialized welfare information was available for 84 species, only 30% of individuals; the remaining 70% either had no welfare publications or were of an unknown species. With aquaculture growth outpacing welfare knowledge, immediate efforts are needed to safeguard the welfare of high-production, understudied species and to create policies that minimize welfare risks.


1998 ◽  
Vol 21 (4) ◽  
pp. 499-511 ◽  
Author(s):  
Peter F. MacNeilage

The species-specific organizational property of speech is a continual mouth open-close alternation, the two phases of which are subject to continual articulatory modulation. The cycle constitutes the syllable, and the open and closed phases are segments – vowels and consonants, respectively. The fact that segmental serial ordering errors in normal adults obey syllable structure constraints suggests that syllabic “frames” and segmental “content” elements are separately controlled in the speech production process. The frames may derive from cycles of mandibular oscillation present in humans from babbling onset, which are responsible for the open-close alternation. These communication- related frames perhaps first evolved when the ingestion-related cyclicities of mandibular oscillation (associated with mastication [chewing] sucking and licking) took on communicative significance as lipsmacks, tonguesmacks, and teeth chatters – displays that are prominent in many nonhuman primates. The new role of Broca's area and its surround in human vocal communication may have derived from its evolutionary history as the main cortical center for the control of ingestive processes. The frame and content components of speech may have subsequently evolved separate realizations within two general purpose primate motor control systems: (1) a motivation-related medial “intrinsic” system, including anterior cingulate cortex and the supplementary motor area, for self-generated behavior, formerly responsible for ancestral vocalization control and now also responsible for frames, and (2) a lateral “extrinsic” system, including Broca's area and surround, and Wernicke's area, specialized for response to external input (and therefore the emergent vocal learning capacity) and more responsible for content.


2021 ◽  
Author(s):  
Anne C Sabol ◽  
Alison L Greggor ◽  
Bryce Masuda ◽  
Ronald R Swaisgood

Vocal communication serves an important role in driving animals' social interactions and ultimately their survival. However, natural vocal behavior can erode in human care. Determining if animals in conservation breeding programs exhibit and respond appropriately to species-specific vocalizations is therefore important for ensuring their survival post-release. We tested whether endangered 'alala (Corvus hawaiiensis), which are extinct in nature, have retained their natural responses to survival-relevant vocal calls. We conducted our studies on breeding populations derived from a small number of founding 'alala maintained in human care since their extinction in the wild in 2002. We presented pairs of 'alala with alarm, territorial intrusion, and two types of control playback calls (a non-threatening territorial maintenance call and a novel heterospecific call). 'Alala were significantly more likely to approach the speaker following alarm call playback than other call types, and were more likely to respond to territorial intrusion calls with the same aggressive territorial calls. Males were more likely to make these aggressive calls than females, mirroring their roles in territory defense. We also found individual consistency in the level of vocal behavior response across all call types, indicating that some individuals are more vocal than others. These results are encouraging, showing that 'alala exhibit relevant, species-specific behaviors despite generations under human care. It does illustrate, however, that all individuals do not respond uniformly, so vocal response may be an important factor to consider in determining the release suitability of individuals.


2019 ◽  
pp. 135406881988013
Author(s):  
Andrea Ceron ◽  
Elisa Volpi

What are the effects of party defections on the attitudes of politicians who remain loyal to the party? We answer by combining multiple sources of data into a comprehensive novel data set on parliamentary party switching, to estimate how this affects the perceived distance between a politician and his party. Focusing on the theory of cognitive dissonance and the black sheep effect, we hypothesize that politicians perceive themselves closer to their parties when those parties recently suffered defections. The effect should be greater among incumbent politicians as they directly experience divisions, but also among officials dissatisfied with the leadership as their dissonance should be stronger. Statistical analyses of data from two elite surveys, on a sample of 13,256 politicians belonging to 92 parties that ran in 28 elections held between 2005 and 2015 in 14 countries, provide support for our hypotheses and shed light on the consequences of intra-party defections.


Viruses ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 902 ◽  
Author(s):  
Shannon M. Murray ◽  
Maxine L. Linial

Foamy viruses (FVs), also known as spumaretroviruses, are complex retroviruses that are seemingly nonpathogenic in natural hosts. In natural hosts, which include felines, bovines, and nonhuman primates (NHPs), a large percentage of adults are infected with FVs. For this reason, the effect of FVs on infections with other viruses (co-infections) cannot be easily studied in natural populations. Most of what is known about interactions between FVs and other viruses is based on studies of NHPs in artificial settings such as research facilities. In these settings, there is some indication that FVs can exacerbate infections with lentiviruses such as simian immunodeficiency virus (SIV). Nonhuman primate (NHP) simian FVs (SFVs) have been shown to infect people without any apparent pathogenicity. Humans zoonotically infected with simian foamy virus (SFV) are often co-infected with other viruses. Thus, it is important to know whether SFV co-infections affect human disease.


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