Researchers in MIT’s CSAIL and CETI project are using machine learning to decipher the “phonetic alphabet of the sperm whale,” revealing complex communication patterns and deepening our understanding of animal language systems.

This study, which analyzed thousands of Caribbean sperm whales, revealed a complex, structured communication system that challenges the idea that complex communication is unique to humans. This work not only advances our understanding of marine biology, but also contributes to broader conservation efforts and parallel research into alien communication.

Whales in myth and science

For thousands of years, the fascination of whales has excited the human consciousness, considering these ocean giants as mysterious inhabitants of the sea depths. From the biblical Leviathan to Herman Melville’s majestic Moby Dick, whales are at the center of mythology and folklore. Although cetology, or whale science, has improved our knowledge of these marine mammals, especially in the last century, studying whales has remained a major challenge.

Now, thanks to machine learning, we’re a little closer to understanding these gentle giants. Researchers at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) and the CETI (Cecetalar Translation Initiative) project recently used algorithms to decipher the “sperm whale phonetic alphabet,” revealing complex structures in sperm whale communication that are similar to human phonetic and communication systems. in other countries. animal kinds

Discovery of sperm whale communication

A new open access study recently published in the journal Nature Communication The study shows that sperm whale codes, or the short clicks they use to communicate, vary significantly in structure depending on the context of the conversation, revealing much more about the communication system. is more complex than previously understood.

The nine thousand codes observed by the Dominican Sperm Whale Project in Eastern Caribbean sperm whale families became an important starting point in unraveling the complex communication system of these creatures. In addition to data collection, the team used image recognition and classification algorithms as well as body recording equipment. It turns out that sperm whale communication is not actually random or simple, but is structured in a complex, combinatorial way.

Acoustic Labeling article

The researchers identified something like a “sperm whale phonetic alphabet,” in which various elements they call “rhythm,” “tempo,” “rubato,” and “ornamentation” interact to form a broad array of discernible codes. For example, whales systematically varied certain aspects of their codas based on speech context; for example, seamlessly changing the duration (rubato) of their calls or adding additional decorative clicks. But even more remarkable, they found that the basic building blocks of these codes can be combined in a combinatorial manner, allowing whales to produce a wide repertoire of different vocalizations.

The experiments were conducted using acoustic biological tags (specifically so-called “D tags”) fitted to whales belonging to the Eastern Caribbean clade. These tags captured the intricate details of the whales’ vocal patterns. Developing new data visualization and analysis techniques, CSAIL researchers found that individual sperm whales can emit different patterns of code during long exchanges, rather than repeating the same code. These patterns, they say, are subtle and include fine-grained variations that other whales also create and recognize.

“Our findings point to the existence of structured information content and also challenge the popular view of many linguists that complex communication is unique to humans,” says Daniela Rus. “Our next steps will be to unravel the meaning behind these messages and explore the relationships between what is said and group actions at a social level.” Credit: Alex Shipps/MIT CSAIL

The importance of whale communication

“We are pushing into the unknown to decipher the secrets of sperm whale communication without any prior ground truth data,” says Daniela Roos, director of CSAIL and professor of electrical engineering and computer science (EECS) at MIT. “Using machine learning is important to identify the characteristics of their communication and predict what they will say next.

“Our results demonstrate the existence of structured information content and also challenge the popular view of many linguists that complex communication is unique to humans. This is a step towards showing that previously undiscovered levels of communication complexity in other species are deeply linked to behavior. Our next steps are to decipher the meaning behind these messages.” and to explore the relationships between what is said and group actions at the social level.”

whaling

The sperm whale has the largest brain of any known animal. This is accompanied by highly complex social behaviors within families and cultural groups that require strong communication for coordination, especially under pressure conditions such as deep-sea fishing.

Whales owe a great debt to MacArthur Fellow Roger Payne, a former CETI project consultant, whale biologist, conservationist, and key figure in shaping their musical careers. In a famous article Science In 1971’s Humpback Whale Songs Payne documented how whales could sing. Their work later became the catalyst for the Save the Whales movement, a successful and timely conservation initiative.

“Roger’s research highlights the impact of science on society. His discovery that whales sing led to passage of the Marine Mammal Protection Act and helped save many whale species from extinction. This interdisciplinary research now brings us closer to what sperm whales sing.” says David Gruber, CETI Project Leader and Founder and Distinguished Professor of Biology at the City University of New York.

Future CETI research now aims to determine whether elements such as rhythm, tempo, ornamentation, and rubato carry specific communicative intentions and could potentially provide insight into “pattern duality,” a linguistic phenomenon in which simple elements combine to convey complex meanings previously thought to be unique. to human language.

Aliens are among us

“One of the intriguing aspects of our study is that it fits a hypothetical scenario of contact with an alien species,” said Pratyusha Sharma, a CSAIL member and MIT PhD student in EECS who is the study’s lead author. “This involves a completely different environment and communication protocols where interactions differ significantly from human norms.” “It’s about understanding a species with different characteristics,” he says. “We investigate how to interpret the basic units of meaning in their communications. It’s not just about teaching animals a subset of human language, it’s also about decoding a naturally evolving communication system within their unique biological and ecological constraints. “Fundamentally, our work could lay the groundwork for deciphering how an ‘alien civilization’ might communicate and provide insight into the creation of algorithms or systems to understand completely unfamiliar forms of communication.”

“Many animal species have a repertoire of several different signals, but we are just beginning to understand the extent to which they combine these signals to create new messages,” said Robert Seyfarth, professor emeritus of psychology at the University of Pennsylvania. did not participate in the research. research.

“Scientists are particularly interested in whether combinations of signals vary depending on the social or environmental context in which they are presented, and in the extent to which combinations of signals obey distinct ‘rules’ that listeners recognize. The problem is particularly difficult when it comes to cetaceans, because scientists often cannot see their subjects or determine the content of the communication in full detail.” “However, this paper provides new and intriguing details about call combinations and their underlying rules in sperm whales.”