Sturdy, Smith, & George (2021) investigated whether dogs detect the natural correlation between pitch and timbre in human voices. Pitch is primarily determined by the fundamental frequency of the vocal folds, while timbre is influenced by vocal tract length. In humans, these features co-vary: men’s longer vocal tracts produce lower pitch and darker timbre, while women’s shorter vocal tracts result in higher pitch and brighter timbre.
To test canine sensitivity, researchers recorded a female voice delivering commands (“Sit,” “Lay down,” “Come here”). They then manipulated the recordings to adjust pitch, timbre, or both. Dogs responded normally to the original female voice and to synthesized male voices where pitch and timbre were altered together. However, when only one attribute—either pitch or timbre—was altered in isolation, dogs were less likely to obey commands.
These results suggest that dogs are not just passively responding to sound but are attuned to the natural covariation of human vocal cues. This ability likely supports their capacity to interpret human speech and categorize speaker identity, reinforcing the depth of dog–human communication.
Source: Sturdy, S. K., Smith, D. R. R., & George, D. N. (2021). Domestic dogs (Canis lupus familiaris) are sensitive to the correlation between pitch and timbre in human speech. Journal: Animal Cognition, Volume 25, Pages 545–554. Publication Date: 2021-10-29. Authors: Sasha K. Sturdy, David R. R. Smith, David N. George. References: 53. Citations: 2.
