Dogs howling to the theme song from “Law and Order” could give us insight into how humans became a musical species, and could even give insights into how language evolved.
Ani Patel (Tufts University), a fellow in the Azrieli Program in Brain, Mind & Consciousness, is one of the few researchers pursuing cross species musical research. His most recent work took him to Youtube, where thanks to a popular internet meme he was able to study whether dogs can intentionally adjust pitch – a capability previously thought to be limited to humans.
Patel found that nine of the 10 dogs he studied were capable of holding stable pitches when howling, and three were able to restrain their howling to a fairly narrow frequency range equivalent to less than a major second musical interval. Patel and his team presented this initial research at the International Conference on Music Perception and Cognition last month.
The next step is to see if the dogs change their pitch range to coincide with a pitch-adjusted version of the song. “If so, then a key aspect of singing is not uniquely human” said Patel.
Though researchers have been interested the evolution of our musical ability and its relationship to language since Darwin’s time, Patel is one of the few pursuing cross-species research to shed light on the connection.
Previously, Patel and his team showed that another species could move in synchrony with a musical beat across a wide range of tempi. They showed that parrots have the ability, which surprisingly our close relatives chimpanzees and monkeys seem to lack. Unlike chimps or monkeys, parrots can imitate complex sounds. Patel has argued that the brain circuitry for ‘vocal learning’ (which humans and parrots share, and which we use to learn the sounds of speech) laid the foundations for the evolution of beat processing.
While some birds may share the human sense of rhythm, Patel has found that when songbirds learn to recognize human melodies, they use very different acoustic cues than humans do. His recent paper in the Proceedings of the National Academy of Sciences shows that “they process melodies more like the way we process speech,” says Patel. “This shows that our mental experience of melody may be very different from many other species.” Patel’s recent work with dogs is an effort to see if other species can coordinate pitches the same way that humans do.
“One of the things that people do all over the world when they sing is that they sing with others. When you sing with others you consciously try to regulate your pitches in relation to other people’s pitches,” he says. Some researchers believe the ability is unique to humans, possibly arising to support group musical behavior and social bonding.
To test whether only humans have this ability, one needs to study other animals that vocalize together. “There’s not that many animals out there that do prolonged pitch vocalizations in groups,” says Patel. “One such species is wolves, who howl in packs.”
Patel hit on the idea of studying dogs howling to music. Dogs are descended from wolves, and “certain dogs howl reliably to specific pieces of music, probably because something in the music sounds howl-like to them,” he says.
Patel also wants to study dogs to examine the extent to which other animals share some of our capacities for processing structure in sequences of sound. Particularly, he wants to explore whether dogs can acquire implicit knowledge of harmonic structure through exposure to music.
“One of the precursors for syntactic processing in language is just acquiring some basic understanding of how the pieces of a communication system fit together,” says Patel. That means implicitly learning that there are principles by which words are combined into sentences and by which tones are combined into melodies. Some of the same cognitive processes that allow us to grasp the structure of music also seem to be important for language development.
Patel says human brains seem to be ready to pick up patterns of words and tones, probably because evolution has adapted them to do so. For example, children develop knowledge of language and musical patterns through exposure, without formal instruction about what the structural rules are.
“If we’re interested in whether evolution has specialized our brains for that then we want to look at whether other animals spontaneously pick up those things when they’re exposed to them,” says Patel.
He thinks dogs, having lived with humans for thousands of years and been exposed to human music, could be a viable model for behavioral research on music perception. In a recent brief for the Psychonomic Bulletin & Review, he cites research showing that dogs are more attentive to human behavior and cues than primates, possess a hearing range and frequency resolution capable of basic music perception, and have an auditory short-term memory better than monkeys, all of which should allow them to learn musical patterns.
If dogs do indeed develop knowledge of musical structure through extended exposure, it would mean the ability to learn a grammatical (rule-based) system though mere exposure is not a unique feature of human cognition and consciousness.
Patel notes that since dogs are now being studied in brain-imaging experiments, one could eventually study the neural responses of dogs to musical structure, and also study their neural reward pathways to see if they experience pleasure from music in a similar way to humans.
“I don’t think anybody’s studied dog music cognition from a scientific stand point,” he says. “Being part of CIFAR is helping me think outside the box in terms of ways of approaching the evolution of human cognition. I think it’s making me more willing to pursue these questions and to see them in a bigger framework of what’s distinct about human consciousness.”