Communication and Language in Animals

Abstract

AbstractEven before Darwin’s time, scholars speculated about the ability of animals to communicate and whether animals have language. Language is universal among humans, but language as vocalized speech utilizes orofacial musculature, and not all animals are as biologically equipped as humans. The origins of language have been conjectured since the seventeenth century, but the mouth-gesture theory has only recently been formalized and examined systematically. Brain localization in the left hemisphere for handedness asymmetry and speech is thought to support the theory, particularly since this has not been found in nonhuman primates. Recent discovery of “mirror” neurons in the brain contained in a neurological network that includes the motor region, Broca’s and Wernicke’s areas, and the orbitofrontal cortex suggests that speech and vocalization evolved from gesture in humans. It appears that at least one of Homo sapiens ancestors, Neanderthals, who had similarly shaped skulls, may also have had language.A related finding important to language was the discovery of the FOXP2 gene, a mutation in which results in verbal dyspraxia in humans. The FOXP2 gene has also been found in the remains of Neanderthals. Interestingly, despite the fact that nonhuman primates also display neural networks similar to humans and bear a FOXP2 gene that differs by only two amino acids, they have not developed communication abilities that would be considered language. One argument as to why language development has been lacking in nonhuman primates has been that their craniofacial musculature and vocal tract differ from both humans and Neanderthals.The FOXP2 gene belongs to a family of proteins that act as transcription regulators and is involved in the regulation of the development of the basal ganglia, which affects motor activity, and in related subcortical structures. The FOXP2 protein is highly conserved in certain songbirds and mammals and differs by only three amino acids in mice. Human language learning and bird song learning share many commonalities in the brain and behavior. Interestingly, impaired motor learning has been found in heterozygous Foxp2 ko mice. Vocal learning is a central feature of human language and has also been documented in some bird species but not in nonhuman primates. In this chapter, I hope to highlight what is known from anthropology, neurology, neurobiology, and genetics about language and communication in Homo sapiens and its predecessors and describe the similarities and differences between human and our nearest genetic nonhuman primates, as well as other vocalizing animals.Key wordsLanguageGestureVocalizationMirror neurons FOXP2 geneOrofacial musculatureSongbirdsNonhuman primatesNeanderthals