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An Introduction to Animal Communication

The ability to communicate effectively with other individuals plays a critical role in the lives of all animals. Whether we are examining how moths attract a mate, ground squirrels convey information about nearby predators, or chimpanzees maintain positions in a dominance hierarchy, communication systems are involved. Here, I provide a primer about the types of communication signals used by animals and the variety of functions they serve. Animal communication is classically defined as occurring when “...the action of or cue given by one organism [the sender] is perceived by and thus alters the probability pattern of behavior in another organism [the receiver] in a fashion adaptive to either one both of the participants” (Wilson 1975). While both a sender and receiver must be involved for communication to occur (Figure 1), in some cases only one player benefits from the interaction. For example, female Photuris fireflies manipulate smaller, male Photinus fireflies by mimicking the flash signals produced by Photinus females. When males investigate the signal, they are voraciously consumed by the larger firefly (Lloyd 1975; Figure 2). This is clearly a case where the sender benefits and the receiver does not. Alternatively, in the case of fringe-lipped bats, Trachops cirrhosus , and tungara frogs, Physalaemus pustulosus , the receiver is the only player that benefits from the interaction. Male tungara frogs produce advertisement calls to attract females to their location; while the signal is designed to be received by females, eavesdropping fringe-lipped bats also detect the calls, and use that information to locate and capture frogs (Ryan et al . 1982). Despite these examples, there are many cases in which both the sender and receiver benefit from exchanging information. Greater sage grouse nicely illustrate such “true communication”; during the mating season, males produce strutting displays that are energetically expensive, and females use this honest information about male quality to choose which individuals to mate with (Vehrencamp et al . 1989).

Figure 1 A model of animal communication.

Figure 2:  Photinus fireflies. Courtesy of Tom Eisner.

Signal Modalities

Animals use a variety of sensory channels, or signal modalities, for communication. Visual signals are very effective for animals that are active during the day. Some visual signals are permanent advertisements; for example, the bright red epaulets of male red-winged blackbirds, Agelaius phoeniceus, which are always displayed, are important for territory defense. When researchers experimentally blackened epaulets, males were subject to much higher rates of intrusion by other males (Smith 1972). Alternatively, some visual signals are actively produced by an individual only under appropriate conditions. Male green anoles, Anolis carolinensis, bob their head and extend a brightly colored throat fan (dewlap) when signaling territory ownership. Acoustic communication is also exceedingly abundant in nature, likely because sound can be adapted to a wide variety of environmental conditions and behavioral situations. Sounds can vary substantially in amplitude, duration, and frequency structure, all of which impact how far the sound will travel in the environment and how easily the receiver can localize the position of the sender. For example, many passerine birds emit pure-tone alarm calls that make localization difficult, while the same species produce more complex, broadband mate attraction songs that allow conspecifics to easily find the sender (Marler 1955). A particularly specialized form of acoustic communication is seen in microchiropteran bats and cetaceans that use high-frequency sounds to detect and localize prey. After sound emission, the returning echo is detected and processed, ultimately allowing the animal to build a picture of their surrounding environment and make very accurate assessments of prey location. Compared to visual and acoustic modalities, chemical signals travel much more slowly through the environment since they must diffuse from the point source of production. Yet, these signals can be transmitted over long distances and fade slowly once produced. In many moth species, females produce chemical cues and males follow the trail to the female’s location. Researchers attempted to tease apart the role of visual and chemical signaling in silkmoths, Bombyx mori , by giving males the choice between a female in a transparent airtight box and a piece of filter paper soaked in chemicals produced by a sexually receptive female. Invariably, males were drawn to the source of the chemical signal and did not respond to the sight of the isolated female (Schneider 1974; Figure 3). Chemical communication also plays a critical role in the lives of other animals, some of which have a specialized vomeronasal organ that is used exclusively to detect chemical cues. For example, male Asian elephants, Elaphus maximus , use the vomeronasal organ to process chemical cues in female’s urine and detect if she is sexually receptive (Rasmussen et al . 1982).

Figure 3 Male silkmoths are more strongly attracted to the pheromones produced by females (chemical signal) than the sight of a female in an airtight box (visual signal). Tactile signals, in which physical contact occurs between the sender and the receiver, can only be transmitted over very short distances. Tactile communication is often very important in building and maintaining relationship among social animals. For example, chimpanzees that regularly groom other individuals are rewarded with greater levels of cooperation and food sharing (de Waal 1989). For aquatic animals living in murky waters, electrical signaling is an ideal mode of communication. Several species of mormyrid fish produce species-specific electrical pulses, which are primarily used for locating prey via electrolocation, but also allow individuals searching for mates to distinguish conspecifics from heterospecifics. Foraging sharks have the ability to detect electrical signals using specialized electroreceptor cells in the head region, which are used for eavesdropping on the weak bioelectric fields of prey (von der Emde 1998).

Signal Functions

Some of the most extravagant communication signals play important roles in sexual advertisement and mate attraction. Successful reproduction requires identifying a mate of the appropriate species and sex, as well as assessing indicators of mate quality. Male satin bowerbirds, Ptilonorhynchus violaceus , use visual signals to attract females by building elaborate bowers decorated with brightly colored objects. When a female approaches the bower, the male produces an elaborate dance, which may or may not end with the female allowing the male to copulate with her (Borgia 1985). Males that do not produce such visual signals have little chance of securing a mate. While females are generally the choosy sex due to greater reproductive investment, there are species in which sexual roles are reversed and females produce signals to attract males. For example, in the deep-snouted pipefish, Syngnathus typhle , females that produce a temporary striped pattern during the mating period are more attractive to males than unornamented females (Berglund et al . 1997). Communication signals also play an important role in conflict resolution, including territory defense. When males are competing for access to females, the costs of engaging in physical combat can be very high; hence natural selection has favored the evolution of communication systems that allow males to honestly assess the fighting ability of their opponents without engaging in combat. Red deer, Cervus elaphus , exhibit such a complex signaling system. During the mating season, males strongly defend a group of females, yet fighting among males is relatively uncommon. Instead, males exchange signals indicative of fighting ability, including roaring and parallel walks. An altercation between two males most often escalates to a physical fight when individuals are closely matched in size, and the exchange of visual and acoustic signals is insufficient for determining which animal is most likely to win a fight (Clutton-Brock et al . 1979). Communication signals are often critical for allowing animals to relocate and accurately identify their own young. In species that produce altricial young, adults regularly leave their offspring at refugia, such as a nest, to forage and gather resources. Upon returning, adults must identify their own offspring, which can be especially difficult in highly colonial species. Brazilian free-tailed bats, Tadarida brasiliensis , form cave colonies containing millions of bats; when females leave the cave each night to forage, they place their pup in a crèche that contains thousands of other young. When females return to the roost, they face the challenge of locating their own pups among thousands of others. Researchers originally thought that such a discriminatory task was impossible, and that females simply fed any pups that approached them, yet further work revealed that females find and nurse their own pup 83% of the time (McCracken 1984, Balcombe 1990). Females are able to make such fantastic discriminations using a combination of spatial memory, acoustic signaling, and chemical signaling. Specifically, pups produce individually-distinct “isolation calls”, which the mother can recognize and detect from a moderate distance. Upon closer inspection of a pup, females use scent to further confirm the pup’s identity. Many animals rely heavily on communication systems to convey information about the environment to conspecifics, especially close relatives. A fantastic illustration comes from vervet monkeys, Chlorocebus pygerythrus , in which adults give alarm calls to warn colony members about the presence of a specific type of predator. This is especially valuable as it conveys the information needed to take appropriate actions given the characteristics of the predator (Figure 4). For example, emitting a “cough” call indicates the presence of an aerial predator, such as an eagle; colony members respond by seeking cover amongst vegetation on the ground (Seyfarth & Cheney 1980). Such an evasive reaction would not be appropriate if a terrestrial predator, such as a leopard, were approaching.

Figure 4 Vervet monkeys. Many animals have sophisticated communication signals for facilitating integration of individuals into a group and maintaining group cohesion. In group-living species that form dominance hierarchies, communication is critical for maintaining ameliorative relationships between dominants and subordinates. In chimpanzees, lower-ranking individuals produce submissive displays toward higher-ranking individuals, such as crouching and emitting “pant-grunt” vocalizations. In turn, dominants produce reconciliatory signals that are indicative of low aggression. Communication systems also are important for coordinating group movements. Contact calls, which inform individuals about the location of groupmates that are not in visual range, are used by a wide variety of birds and mammals. Overall, studying communication not only gives us insight into the inner worlds of animals, but also allows us to better answer important evolutionary questions. As an example, when two isolated populations exhibit divergence over time in the structure of signals use to attract mates, reproductive isolation can occur. This means that even if the populations converge again in the future, the distinct differences in critical communication signals may cause individuals to only select mates from their own population. For example, three species of lacewings that are closely related and look identical are actually reproductively isolated due to differences in the low-frequency songs produced by males; females respond much more readily to songs from their own species compared to songs from other species (Martinez, Wells & Henry 1992). A thorough understanding of animal communication systems can also be critical for making effective decisions about conservation of threatened and endangered species. As an example, recent research has focused on understanding how human-generated noise (from cars, trains, etc) can impact communication in a variety of animals (Rabin et al . 2003). As the field of animal communication continues to expand, we will learn more about information exchange in a wide variety of species and better understand the fantastic variety of signals we see animals produce in nature.

Vomeronasal organ – auxiliary olfactory organ that detects chemosensory cues

Altricial – the state of being born in an immature state and relying exclusively on parental care for survival during early development

Refugia – areas that provide concealment from predators and/or protection from harsh environmental conditions

Conspecifics – organisms of the same species

References and Recommended Reading

Balcombe, J.P. Vocal recognition of pups by mother Mexican free-tailed bats, Tadarida brasiliensis mexicana . Animal Behaviour 39 , 960-966 (1990). Berglund, J., Rosenqvist G. and Bernet P. Ornamentation predicts reproductive success in female pipefish. Behavioral Ecology and Sociobiology 40 , 145-150 (1997). Clutton-Brock, T., Albon S., Gibson S. & Guinness F. The logical stag: Adaptive aspects of fighing in the red deer. Animal Behaviour 27 , 211-225 (1979). de Waal F.B.M. Food sharing and reciprocal obligations among chimpanzees. Journal of Human Evolution 18 , 433–459 (1989).

Hauser, M. 1997. The Evolution of Communication . Cambridge, MA: MIT Press. Lloyd, J.E. Aggressive mimicry in Photuris: signal repertoires by femmes fatales. Science 197 , 452-453 (1975).

Marler, P. Characteristics of some animal calls. Nature 176 , 6-8 (1955). Martinez Well, M. & Henry C.S. The role of courtship songs in reproductive isolation among populations of green lacewings of the genus Chrysoperla . Evolution 46 , 31-43 (1992). McCracken, G.F. Communal nursing in Mexican free-tailed bat maternity colonies. Science 223 , 1090-1091(1984).

Rabin, L.A., McCowan B., Hooper S.L & Owings D.H. Anthropogenic noise and its effect on animal communication: an interface between comparative psychology and conservation biology. International Journal of Comparative Psychology 16 , 172-192 (2003). Ryan M.J., Tuttle M.D., & Rand A.S. Sexual advertisement and bat predation in a neotropical frog. American Naturalist 119 , 136–139 (1982). Schneider, D. The sex attractant receptors of moths. Scientific American 231 , 28-35 (1974). Seyfarth, R.M., Cheney D.L. & Marler P. Monkey responses to three different alarm calls: Evidence for predator classification and semantic communication. Science 210 , 801-803 (1980). Smith, D. The role of the epaulets in the red-winged blackbird, ( Agelaius phoeniceus ) social system. Behaviour 41 , 251-268 (1972).

Vehrencamp, S.L., Bradbury J.W., & Gibson R.M. The energetic cost of display in male sage grouse. Animal Behaviour 38 , 885-896 (1989). von der Emde, G. Electroreception. In D. H. Evans (ed.). The Physiology of Fishes , pp. 313-343. Boca Raton, FL: CRC Press (1998). Wilson, E.O. Sociobiology: The New Synthesis . Cambridge, MA: Harvard University Press (1975).

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The Animals Are Talking. What Does It Mean?

Language was long understood as a human-only affair. New research suggests that isn’t so.

Credit... Illustration by Denise Nestor

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By Sonia Shah

• Published Sept. 20, 2023 Updated Sept. 22, 2023

Can a mouse learn a new song?

Such a question might seem whimsical. Though humans have lived alongside mice for at least 15,000 years, few of us have ever heard mice sing, because they do so in frequencies beyond the range detectable by human hearing. As pups, their high-pitched songs alert their mothers to their whereabouts; as adults, they sing in ultrasound to woo one another. For decades, researchers considered mouse songs instinctual, the fixed tunes of a windup music box, rather than the mutable expressions of individual minds.

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But no one had tested whether that was really true. In 2012, a team of neurobiologists at Duke University, led by Erich Jarvis, a neuroscientist who studies vocal learning, designed an experiment to find out. The team surgically deafened five mice and recorded their songs in a mouse-size sound studio, tricked out with infrared cameras and microphones. They then compared sonograms of the songs of deafened mice with those of hearing mice. If the mouse songs were innate, as long presumed, the surgical alteration would make no difference at all.

Jarvis and his researchers slowed down the tempo and shifted the pitch of the recordings, so that they could hear the songs with their own ears. Those of the intact mice sounded “remarkably similar to some bird songs,” Jarvis wrote in a 2013 paper that described the experiment, with whistlelike syllables similar to those in the songs of canaries and the trills of dolphins. Not so the songs of the deafened mice: Deprived of auditory feedback, their songs became degraded, rendering them nearly unrecognizable. They sounded, the scientists noted, like “squawks and screams.” Not only did the tunes of a mouse depend on its ability to hear itself and others, but also, as the team found in another experiment, a male mouse could alter the pitch of its song to compete with other male mice for female attention.

Inside these murine skills lay clues to a puzzle many have called “the hardest problem in science”: the origins of language. In humans, “vocal learning” is understood as a skill critical to spoken language. Researchers had already discovered the capacity for vocal learning in species other than humans, including in songbirds, hummingbirds, parrots, cetaceans such as dolphins and whales, pinnipeds such as seals, elephants and bats. But given the centuries-old idea that a deep chasm separated human language from animal communications, most scientists understood the vocal learning abilities of other species as unrelated to our own — as evolutionarily divergent as the wing of a bat is to that of a bee. The apparent absence of intermediate forms of language — say, a talking animal — left the question of how language evolved resistant to empirical inquiry.

When the Duke researchers dissected the brains of the hearing and deafened mice, they found a rudimentary version of the neural circuitry that allows the forebrains of vocal learners such as humans and songbirds to directly control their vocal organs. Mice don’t seem to have the vocal flexibility of elephants; they cannot, like the 10-year-old female African elephant in Tsavo, Kenya, mimic the sound of trucks on the nearby Nairobi-Mombasa highway. Or the gift for mimicry of seals; an orphaned harbor seal at the New England Aquarium could utter English phrases in a perfect Maine accent (“Hoover, get over here,” he said. “Come on, come on!”).

But the rudimentary skills of mice suggested that the language-critical capacity might exist on a continuum, much like a submerged land bridge might indicate that two now-isolated continents were once connected. In recent years, an array of findings have also revealed an expansive nonhuman soundscape, including: turtles that produce and respond to sounds to coordinate the timing of their birth from inside their eggs; coral larvae that can hear the sounds of healthy reefs ; and plants that can detect the sound of running water and the munching of insect predators . Researchers have found intention and meaning in this cacophony, such as the purposeful use of different sounds to convey information. They’ve theorized that one of the most confounding aspects of language, its rules-based internal structure, emerged from social drives common across a range of species.

With each discovery, the cognitive and moral divide between humanity and the rest of the animal world has eroded. For centuries, the linguistic utterances of Homo sapiens have been positioned as unique in nature, justifying our dominion over other species and shrouding the evolution of language in mystery. Now, experts in linguistics, biology and cognitive science suspect that components of language might be shared across species, illuminating the inner lives of animals in ways that could help stitch language into their evolutionary history — and our own.

For hundreds of years, language marked “the true difference between man and beast,” as the philosopher René Descartes wrote in 1649. As recently as the end of the last century, archaeologists and anthropologists speculated that 40,000 to 50,000 years ago a “human revolution” fractured evolutionary history, creating an unbridgeable gap separating humanity’s cognitive and linguistic abilities from those of the rest of the animal world.

Linguists and other experts reinforced this idea. In 1959, the M.I.T. linguist Noam Chomsky, then 30, wrote a blistering 33-page takedown of a book by the celebrated behaviorist B.F. Skinner, which argued that language was just a form of “verbal behavior,” as Skinner titled the book, accessible to any species given sufficient conditioning. One observer called it “perhaps the most devastating review ever written.” Between 1972 and 1990, there were more citations of Chomsky’s critique than Skinner’s book, which bombed.

The view of language as a uniquely human superpower, one that enabled Homo sapiens to write epic poetry and send astronauts to the moon, presumed some uniquely human biology to match. But attempts to find those special biological mechanisms — whether physiological, neurological, genetic — that make language possible have all come up short.

One high-profile example came in 2001, when a team led by the geneticists Cecilia Lai and Simon Fisher discovered a gene — called FoxP2 — in a London family riddled with childhood apraxia of speech, a disorder that impairs the ability of otherwise cognitively capable individuals to coordinate their muscles to produce sounds, syllables and words in an intelligible sequence. Commentators hailed FoxP2 as the long sought-after gene that enabled humans to talk — until the gene turned up in the genomes of rodents, birds, reptiles, fish and ancient hominins such as Neanderthals, whose version of FoxP2 is much like ours. (Fisher so often encountered the public expectation that FoxP2 was the “language gene” that he resolved to acquire a T-shirt that read, “It’s more complicated than that.”)

The search for an exclusively human vocal anatomy has failed, too. For a 2001 study, the cognitive scientist Tecumseh Fitch cajoled goats, dogs, deer and other species to vocalize while inside a cineradiograph machine that filmed the way their larynxes moved under X-ray. Fitch discovered that species with larynxes different from ours — ours is “descended” and located in our throats rather than our mouths — could nevertheless move them in similar ways. One of them, the red deer, even had the same descended larynx we do.

Fitch and his then-colleague at Harvard, the evolutionary biologist Marc Hauser, began to wonder if they’d been thinking about language all wrong. Linguists described language as a singular skill, like being able to swim or bake a soufflé: You either had it or you didn’t. But perhaps language was more like a multicomponent system that included psychological traits, such as the ability to share intentions; physiological ones, such as motor control over vocalizations and gestures; and cognitive capacities, such as the ability to combine signals according to rules, many of which might appear in other animals as well.

Fitch, whom I spoke to by Zoom in his office at the University of Vienna, drafted a paper with Hauser as a “kind of an argument against Chomsky,” he told me. As a courtesy, he sent the M.I.T. linguist a draft. One evening, he and Hauser were sitting in their respective offices along the same hall at Harvard when an email from Chomsky dinged their inboxes. “We both read it and we walked out of our rooms going, ‘What?’” Chomsky indicated that not only did he agree, but that he’d be willing to sign on to their next paper on the subject as a co-author. That paper, which has since racked up more than 7,000 citations, appeared in the journal Science in 2002.

Squabbles continued over which components of language were shared with other species and which, if any, were exclusive to humans. Those included, among others, language’s intentionality, its system of combining signals, its ability to refer to external concepts and things separated by time and space and its power to generate an infinite number of expressions from a finite number of signals. But reflexive belief in language as an evolutionary anomaly started to dissolve. “For the biologists,” recalled Fitch, “it was like, ‘Oh, good, finally the linguists are being reasonable.’”

Evidence of continuities between animal communication and human language continued to mount. The sequencing of the Neanderthal genome in 2010 suggested that we hadn’t significantly diverged from that lineage, as the theory of a “human revolution” posited. On the contrary, Neanderthal genes and those of other ancient hominins persisted in the modern human genome, evidence of how intimately we were entangled. In 2014, Jarvis found that the neural circuits that allowed songbirds to learn and produce novel sounds matched those in humans, and that the genes that regulated those circuits evolved in similar ways. The accumulating evidence left “little room for doubt,” Cedric Boeckx, a theoretical linguist at the University of Barcelona, noted in the journal Frontiers in Neuroscience. “There was no ‘great leap forward.’”

As our understanding of the nature and origin of language shifted, a host of fruitful cross-disciplinary collaborations arose. Colleagues of Chomsky’s, such as the M.I.T. linguist Shigeru Miyagawa, whose early career was shaped by the precept that “we’re smart, they’re not,” applied for grants with primatologists and neuroscientists to study how human language might be related to birdsong and primate calls. Interdisciplinary centers sprang up devoted specifically to the evolution of language, including at the University of Zurich and the University of Edinburgh. Lectures at a biannual conference on language evolution once dominated by “armchair theorizing,” as the cognitive scientist and founder of the University of Edinburgh’s Centre for Language Evolution, Simon Kirby, put it, morphed into presentations “completely packed with empirical data.”

One of the thorniest problems researchers sought to address was the link between thought and language. Philosophers and linguists long held that language must have evolved not for the purpose of communication but to facilitate abstract thought. The grammatical rules that structure language, a feature of languages from Algonquin to American Sign Language, are more complex than necessary for communication. Language, the argument went, must have evolved to help us think, in much the same way that mathematical notations allow us to make complex calculations.

Ev Fedorenko, a cognitive neuroscientist at M.I.T., thought this was “a cool idea,” so, about a decade ago, she set out to test it. If language is the medium of thought, she reasoned, then thinking a thought and absorbing the meaning of spoken or written words should activate the same neural circuits in the brain, like two streams fed by the same underground spring. Earlier brain-imaging studies showed that patients with severe aphasia could still solve mathematical problems, despite their difficulty in deciphering or producing language, but failed to pinpoint distinctions between brain regions dedicated to thought and those dedicated to language. Fedorenko suspected that might be because the precise location of these regions varied from individual to individual. In a 2011 study, she asked healthy subjects to make computations and decipher snatches of spoken and written language while she watched how blood flowed to aroused parts of their brains using an M.R.I. machine, taking their unique neural circuitry into account in her subsequent analysis. Her fM.R.I. studies showed that thinking thoughts and decoding words mobilized distinct brain pathways . Language and thought, Fedorenko says, “really are separate in an adult human brain.”

At the University of Edinburgh, Kirby hit upon a process that might explain how language’s internal structure evolved. That structure, in which simple elements such as sounds and words are arranged into phrases and nested hierarchically within one another, gives language the power to generate an infinite number of meanings; it is a key feature of language as well as of mathematics and music. But its origins were hazy. Because children intuit the rules that govern linguistic structure with little if any explicit instruction, philosophers and linguists argued that it must be a product of some uniquely human cognitive process. But researchers who scrutinized the fossil record to determine when and how that process evolved were stumped: The first sentences uttered left no trace behind.

Kirby designed an experiment to simulate the evolution of language inside his lab. First, he developed made-up codes to serve as proxies for the disordered collections of words widely believed to have preceded the emergence of structured language, such as random sequences of colored lights or a series of pantomimes. Then he recruited subjects to use the code under a variety of conditions and studied how the code changed. He asked subjects to use the code to solve communication tasks, for example, or to pass the code on to one another as in a game of telephone. He ran the experiment hundreds of times using different parameters on a variety of subjects, including on a colony of baboons living in a seminaturalistic enclosure equipped with a bank of computers on which they could choose to play his experimental games.

What he found was striking: Regardless of the native tongue of the subjects, or whether they were baboons, college students or robots, the results were the same. When individuals passed the code on to one another, the code became simpler but also less precise. But when they passed it on to one another and also used it to communicate, the code developed a distinct architecture. Random sequences of colored lights turned into richly patterned ones; convoluted, pantomimic gestures for words such as “church” or “police officer” became abstract, efficient signs. “We just saw, spontaneously emerging out of this experiment, the language structures we were waiting for,” Kirby says. His findings suggest that language’s mystical power — its ability to turn the noise of random signals into intelligible formulations — may have emerged from a humble trade-off: between simplicity, for ease of learning, and what Kirby called “expressiveness,” for unambiguous communication.

For Descartes, the equation of language with thought meant animals had no mental life at all: “The brutes,” he opined, “don’t have any thought.” Breaking the link between language and human biology didn’t just demystify language; it restored the possibility of mind to the animal world and repositioned linguistic capacities as theoretically accessible to any social species.

The search for the components of language in nonhuman animals now extends to the far reaches of our phylogenetic tree, encompassing creatures that may communicate in radically unfamiliar ways.

This summer, I met with Marcelo Magnasco, a biophysicist, and Diana Reiss, a psychologist at Hunter College who studies dolphin cognition, in Magnasco’s lab at Rockefeller University. Overlooking the East River, it was a warmly lit room, with rows of burbling tanks inhabited by octopuses, whose mysterious signals they hoped to decode. Magnasco became curious about the cognitive and communicative abilities of cephalopods while diving recreationally, he told me. Numerous times, he said, he encountered cephalopods and had “the overpowering impression that they were trying to communicate with me.” During the Covid-19 shutdown, when his work studying dolphin communication with Reiss was derailed, Magnasco found himself driving to a Petco in Staten Island to buy tanks for octopuses to live in his lab.

During my visit, the grayish pink tentacles of the octopus clinging to the side of the glass wall of her tank started to flash bright white. Was she angry? Was she trying to tell us something? Was she even aware of our presence? There was no way to know, Magnasco said. Earlier efforts to find linguistic capacities in other species failed, in part, he explained, because we assumed they would look like our own. But the communication systems of other species might, in fact, be “truly exotic to us,” Magnasco said. A species that can recognize objects by echolocation, as cetaceans and bats can, might communicate using acoustic pictographs, for example, which might sound to us like meaningless chirps or clicks. To disambiguate the meaning of animal signals, such as a string of dolphin clicks or whalesong, scientists needed some inkling of where meaning-encoding units began and ended, Reiss explained. “We, in fact, have no idea what the smallest unit is,” she said. If scientists analyze animal calls using the wrong segmentation, meaningful expressions turn into meaningless drivel: “ad ogra naway” instead of “a dog ran away.”

An international initiative called Project CETI, founded by David Gruber, a biologist at the City University of New York, hopes to get around this problem by feeding recordings of sperm-whale clicks, known as codas, into computer models, which might be able to discern patterns in them, in the same way that ChatGPT was able to grasp vocabulary and grammar in human language by analyzing publicly available text. Another method, Reiss says, is to provide animal subjects with artificial codes and observe how they use them.

Reiss’s research on dolphin cognition is one of a handful of projects on animal communication that dates back to the 1980s, when there were widespread funding cuts in the field, after a top researcher retracted his much-hyped claim that a chimpanzee could be trained to use sign language to converse with humans. In a study published in 1993, Reiss offered bottlenose dolphins at a facility in Northern California an underwater keypad that allowed them to choose specific toys, which it delivered while emitting computer-generated whistles, like a kind of vending machine. The dolphins spontaneously began mimicking the computer-generated whistles when they played independently with the corresponding toy, like kids tossing a ball and naming it “ball, ball, ball,” Reiss told me. “The behavior,” Reiss said, “was strikingly similar to the early stages of language acquisition in children.”

The researchers hoped to replicate the method by outfitting an octopus tank with an interactive platform of some kind and observing how the octopus engaged with it. But it was unclear whether such a device might interest the lone cephalopod. An earlier episode of displeasure led her to discharge enough ink to turn her tank water so black that she couldn’t be seen. Unlocking her communicative abilities might require that she consider the scientists as fascinating as they did her.

While experimenting with animals trapped in cages and tanks can reveal their latent faculties, figuring out the range of what animals are communicating to one another requires spying on them in the wild. Past studies often conflated general communication, in which individuals extract meaning from signals sent by other individuals, with language’s more specific, flexible and open-ended system. In a seminal 1980 study, for example, the primatologists Robert Seyfarth and Dorothy Cheney used the “playback” technique to decode the meaning of alarm calls issued by vervet monkeys at Amboseli National Park in Kenya. When a recording of the barklike calls emitted by a vervet encountering a leopard was played back to other vervets, it sent them scampering into the trees. Recordings of the low grunts of a vervet who spotted an eagle led other vervets to look up into the sky; recordings of the high-pitched chutters emitted by a vervet upon noticing a python caused them to scan the ground.

At the time, The New York Times ran a front-page story heralding the discovery of a “rudimentary ‘language’” in vervet monkeys. But critics objected that the calls might not have any properties of language at all. Instead of being intentional messages to communicate meaning to others, the calls might be involuntary, emotion-driven sounds, like the cry of a hungry baby. Such involuntary expressions can transmit rich information to listeners, but unlike words and sentences, they don’t allow for discussion of things separated by time and space. The barks of a vervet in the throes of leopard-induced terror could alert other vervets to the presence of a leopard — but couldn’t provide any way to talk about, say, “the really smelly leopard who showed up at the ravine yesterday morning.”

Toshitaka Suzuki, an ethologist at the University of Tokyo who describes himself as an animal linguist, struck upon a method to disambiguate intentional calls from involuntary ones while soaking in a bath one day. When we spoke over Zoom, he showed me an image of a fluffy cloud. “If you hear the word ‘dog,’ you might see a dog,” he pointed out, as I gazed at the white mass. “If you hear the word ‘cat,’ you might see a cat.” That, he said, marks the difference between a word and a sound. “Words influence how we see objects,” he said. “Sounds do not.” Using playback studies, Suzuki determined that Japanese tits, songbirds that live in East Asian forests and that he has studied for more than 15 years, emit a special vocalization when they encounter snakes. When other Japanese tits heard a recording of the vocalization, which Suzuki dubbed the “jar jar” call, they searched the ground, as if looking for a snake. To determine whether “jar jar” meant “snake” in Japanese tit, he added another element to his experiments : an eight-inch stick, which he dragged along the surface of a tree using hidden strings. Usually, Suzuki found, the birds ignored the stick. It was, by his analogy, a passing cloud. But then he played a recording of the “jar jar” call. In that case, the stick seemed to take on new significance: The birds approached the stick, as if examining whether it was, in fact, a snake. Like a word, the “jar jar” call had changed their perception.

Cat Hobaiter, a primatologist at the University of St. Andrews who works with great apes, developed a similarly nuanced method. Because great apes appear to have a relatively limited repertoire of vocalizations, Hobaiter studies their gestures. For years, she and her collaborators have followed chimps in the Budongo forest and gorillas in Bwindi in Uganda, recording their gestures and how others respond to them. “Basically, my job is to get up in the morning to get the chimps when they’re coming down out of the tree, or the gorillas when they’re coming out of the nest, and just to spend the day with them,” she told me. So far, she says, she has recorded about 15,600 instances of gestured exchanges between apes.

To determine whether the gestures are involuntary or intentional, she uses a method adapted from research on human babies. Hobaiter looks for signals that evoke what she calls an “Apparently Satisfactory Outcome.” The method draws on the theory that involuntary signals continue even after listeners have understood their meaning, while intentional ones stop once the signaler realizes her listener has comprehended the signal. It’s the difference between the continued wailing of a hungry baby after her parents have gone to fetch a bottle, Hobaiter explains, and my entreaties to you to pour me some coffee, which cease once you start reaching for the coffeepot. To search for a pattern, she says she and her researchers have looked “across hundreds of cases and dozens of gestures and different individuals using the same gesture across different days.” So far, her team’s analysis of 15 years’ worth of video-recorded exchanges has pinpointed dozens of ape gestures that trigger “apparently satisfactory outcomes.”

These gestures may also be legible to us, albeit beneath our conscious awareness. Hobaiter applied her technique on pre-verbal 1- and 2-year-old children, following them around recording their gestures and how they affected attentive others, “like they’re tiny apes, which they basically are,” she says. She also posted short video clips of ape gestures online and asked adult visitors who’d never spent any time with great apes to guess what they thought they meant. She found that pre-verbal human children use at least 40 or 50 gestures from the ape repertoire, and adults correctly guessed the meaning of video-recorded ape gestures at a rate “significantly higher than expected by chance,” as Hobaiter and Kirsty E. Graham, a postdoctoral research fellow in Hobaiter’s lab, reported in a 2023 paper for PLOS Biology.

The emerging research might seem to suggest that there’s nothing very special about human language. Other species use intentional wordlike signals just as we do. Some, such as Japanese tits and pied babblers, have been known to combine different signals to make new meanings. Many species are social and practice cultural transmission, satisfying what might be prerequisite for a structured communication system like language. And yet a stubborn fact remains. The species that use features of language in their communications have few obvious geographical or phylogenetic similarities. And despite years of searching, no one has discovered a communication system with all the properties of language in any species other than our own.

For some scientists, the mounting evidence of cognitive and linguistic continuities between humans and animals outweighs evidence of any gaps. “There really isn’t such a sharp distinction,” Jarvis, now at Rockefeller University, said in a podcast. Fedorenko agrees. The idea of a chasm separating man from beast is a product of “language elitism,” she says, as well as a myopic focus on “how different language is from everything else.”

But for others, the absence of clear evidence of all the components of language in other species is, in fact, evidence of their absence. In a 2016 book on language evolution titled “Why Only Us,” written with the computer scientist and computational linguist Robert C. Berwick, Chomsky describes animal communications as “radically different” from human language. Seyfarth and Cheney, in a 2018 book, note the “striking discontinuities” between human and nonhuman loquacity. Animal calls may be modifiable; they may be voluntary and intentional. But they’re rarely combined according to rules in the way that human words are and “appear to convey only limited information,” they write. If animals had anything like the full suite of linguistic components we do, Kirby says, we would know by now. Animals with similar cognitive and social capacities to ours rarely express themselves systematically the way we do, with systemwide cues to distinguish different categories of meaning. “We just don’t see that kind of level of systematicity in the communication systems of other species,” Kirby said in a 2021 talk.

This evolutionary anomaly may seem strange if you consider language an unalloyed benefit. But what if it isn’t? Even the most wondrous abilities can have drawbacks. According to the popular “self-domestication” hypothesis of language’s origins, proposed by Kirby and James Thomas in a 2018 paper published in Biology & Philosophy, variable tones and inventive locutions might prevent members of a species from recognizing others of their kind. Or, as others have pointed out, they might draw the attention of predators. Such perils could help explain why domesticated species such as Bengalese finches have more complex and syntactically rich songs than their wild kin, the white-rumped munia, as discovered by the biopsychologist Kazuo Okanoya in 2012; why tamed foxes and domesticated canines exhibit heightened abilities to communicate, at least with humans, compared with wolves and wild foxes; and why humans, described by some experts as a domesticated species of their ape and hominin ancestors, might be the most talkative of all. A lingering gap between our abilities and those of other species, in other words, does not necessarily leave language stranded outside evolution. Perhaps, Fitch says, language is unique to Homo sapiens, but not in any unique way: special to humans in the same way the trunk is to the elephant and echolocation is to the bat.

The quest for language’s origins has yet to deliver King Solomon’s seal, a ring that magically bestows upon its wearer the power to speak to animals, or the future imagined in a short story by Ursula K. Le Guin, in which therolinguists pore over the manuscripts of ants, the “kinetic sea writings” of penguins and the “delicate, transient lyrics of the lichen.” Perhaps it never will. But what we know so far tethers us to our animal kin regardless. No longer marooned among mindless objects, we have emerged into a remade world, abuzz with the conversations of fellow thinking beings, however inscrutable.

Sonia Shah is a science journalist and the author, most recently, of “The Next Great Migration: The Beauty and Terror of Life on the Move.” She is currently writing a book on the history and science of human exceptionalism. Denise Nestor is an artist and illustrator in Dublin. She is known for her finely detailed hand-drawn art, often inspired by nature.

An earlier version of this story referred incorrectly to Robert C. Berwick’s field of study. He is a computer scientist and computational linguist, not a linguist.

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February 7, 2023

How Scientists Are Using AI to Talk to Animals

Portable sensors and artificial intelligence are helping researchers decode animal communication—and begin to talk back to nonhumans

By Sophie Bushwick

Irene Rinaldi

In the 1970s a young gorilla known as Koko drew worldwide attention with her ability to use human sign language. But skeptics maintain that Koko and other animals that “learned” to speak (including chimpanzees and dolphins) could not truly understand what they were “saying”—and that trying to make other species use human language , in which symbols represent things that may not be physically present, is futile.

“There's one set of researchers that's keen on finding out whether animals can engage in symbolic communication and another set that says, ‘That is anthropomorphizing. We need to understand nonhuman communication on its own terms,’” says Karen Bakker, a professor at the University of British Columbia and a fellow at the Harvard Radcliffe Institute for Advanced Study. Now scientists are using improved sensors and artificial-intelligence technology to observe and decode how a broad range of species, including plants , already share information with their own methods. This field of “digital bioacoustics” is the subject of Bakker's 2022 book The Sounds of Life: How Digital Technology Is Bringing Us Closer to the Worlds of Animals and Plants (Princeton University Press).

Scientific American spoke with Bakker about how technology can help humans communicate with creatures such as bats and honeybees —and how these conversations are forcing us to rethink our relationship with other species.

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[ An edited transcript of the interview follows. ]

Can you give us a brief history of humans attempting to communicate with animals?

There were numerous attempts in the mid-20th century to try to teach human language to nonhumans, primates such as Koko. And those efforts were somewhat controversial. As we look back, one view we have now (that may not have been so prevalent then) is that we were too anthropocentric in our approaches. The desire then was to assess nonhuman intelligence by teaching nonhumans to speak like we do—when in fact we should have been thinking about their abilities to engage in complex communication on their own terms, in their own embodied way, in their own worldview.

One of the terms used in the book is the notion of umwelt , which is this idea of the lived experience of organisms. If we are attentive to the umwelt of another organism, we wouldn't expect a honeybee to speak human language, but we would become very interested in the fascinating language of honeybees, which is vibrational and positional. It's sensitive to nuances such as the polarization of sunlight that we can't even begin to convey with our bodies. That is where the science is today. The field of digital bioacoustics—which is accelerating exponentially and unveiling fascinating findings about communication across the tree of life—is now approaching these animals and asking not “Can they speak like humans?” but “Can they communicate complex information to one another? How are they doing so? What is significant to them?” I would say that's a more biocentric approach, or at the very least it's less anthropocentric.

Taking a bigger view, I think it's also important to acknowledge that listening to nature, “deep listening,” has a long and venerable tradition. It's an ancient art that is still practiced in an unmediated form. There are long-standing Indigenous traditions of deep listening that are deeply attuned to nonhuman sounds. So if we combine digital listening—which is opening up vast new worlds of nonhuman sound and decoding that sound with artificial intelligence—with deep listening, I believe that we are on the brink of two important discoveries. The first is language in nonhumans. And that's a very controversial statement, which we can dig into. The second is: I believe we're at the brink of interspecies communication.

What kind of technology is enabling these breakthroughs?

Digital bioacoustics relies on very small, portable, lightweight digital recorders, which are like miniature microphones that scientists are installing everywhere from the Arctic to the Amazon. You can put these microphones on the backs of turtles or whales. You can put them deep in the ocean or on the highest mountaintop or attach them to birds. They can record continuously, 24/7, in remote places scientists cannot easily reach, even in the dark, and without the disruption that comes from introducing human observers in an ecosystem.

That instrumentation creates a data deluge, and that is where artificial intelligence comes in—because the same natural-language-processing algorithms that we are using to such great effect in tools such as Google Translate can also be used to detect patterns in nonhuman communication.

What's an example of these communication patterns?

In the bat chapter where I discuss the research of Yossi Yovel of Tel Aviv University, there's a particular study in which his team monitored [nearly two] dozen Egyptian fruit bats for two and a half months and recorded their vocalizations. They then adapted a voice-recognition program to analyze [15,000 of] the sounds, and the algorithm correlated specific sounds with specific social interactions captured via videos—such as when two bats fought over food. Using this, the researchers were able to classify the majority of bats' sounds. That is how Yovel and other researchers such as Gerry Carter of the Ohio State University have been able to determine that bats have much more complex language than we previously understood. Bats argue over food; they distinguish between genders when they communicate with one another; they have individual names , or “signature calls.” Mother bats speak to their babies in an equivalent of “ motherese .” But whereas human mothers raise the pitch of their voices when talking to babies, mother bats lower the pitch—which elicits a babble response in the babies that learn to “speak” specific words or referential signals as they grow up. So bats engage in vocal learning.

That's a great example of how deep learning is able to derive these patterns from this instrumentation, all of these sensors and microphones, and reveal to us something that we could not access with the naked human ear. Because most of bat communication is in the ultrasonic, above our hearing range, and because bats speak much faster than we do, we have to slow it down to listen to it, as well as reduce the frequency. So we cannot listen like a bat, but our computers can. The next insight is that our computers can also speak back to the bat. The software produces specific patterns and uses those to communicate back to the bat colony or to the beehive, and that is what researchers are now doing.

How are researchers talking to bees?

The honeybee research is fascinating. A researcher named Tim Landgraf of Freie Universität Berlin studies bee communication, which, as I mentioned earlier, is vibrational and positional. When honeybees “speak” to one another, it's their body movements, as well as the sounds, that matter. Now computers, and particularly deep-learning algorithms, are able to follow this because you can use computer vision, combined with natural-language processing. They have now perfected these algorithms to the point where they're actually able to track individual bees, and they're able to determine what impact the communication of an individual might have on another bee. From that emerges the ability to decode honeybee language. We found that they have specific signals. Researchers have given these signals funny names. Bees toot; they quack. There's a “hush” or “stop” signal, a whooping “danger” signal. They've got piping [signals related to swarming] and begging and shaking signals, and those all direct collective and individual behavior .

The next step for Landgraf was to encode this information into a robot that he called RoboBee. Eventually, after seven or eight prototypes, he came up with a “bee” that could enter the hive, and it would essentially emit commands that the honeybees would obey. So Landgraf's honeybee robot can tell the other bees to stop, and they do. It can also do something more complicated, which is the very famous waggle dance—it's the communication pattern they use to convey the location of a nectar source to other honeybees. This is a very easy experiment to run, in a way, because you put a nectar source in a place where no honeybees from the hive have visited. You then instruct the robot to tell the honeybees where the nectar source is, and then you check whether the bees fly there successfully. And indeed, they do. This result happened only once, and scientists are not sure why it worked or how to replicate it. But it is still an astounding result.

This raises a lot of philosophical and ethical questions. You could imagine such a system being used to protect honeybees—you could tell honeybees to fly to safe nectar sources and not polluted ones that had, let's say, high levels of pesticides. You could also imagine this could be a tool to domesticate a previously wild species that we have only imperfectly domesticated or to attempt to control the behavior of other wild species. The insights about the level of sophistication and the degree of complex communication in nonhumans raise some very important philosophical questions about the uniqueness of language as a human capacity.

What impact is this technology having on our understanding of the natural world?

The invention of digital bioacoustics is analogous to the invention of the microscope. When Dutch scientist Antonie van Leeuwenhoek started looking through his microscopes, he discovered the microbial world, and that laid the foundation for countless future breakthroughs. So the microscope enabled humans to see anew with both our eyes and our imaginations. The analogy here is that digital bioacoustics, combined with artificial intelligence, is like a planetary-scale hearing aid that enables us to listen anew with both our prosthetically enhanced ears and our imagination. This is slowly opening our minds not only to the wonderful sounds that nonhumans make but to a fundamental set of questions about the so-called divide between humans and nonhumans, our relationship to other species. It's also opening up new ways to think about conservation and our relationship to the planet. It's pretty profound.

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• 1 Department of Psychology, University of Maryland, Baltimore, MD, United States
• 2 Department of Biology and the Center for Translational Social Neuroscience, Emory University, Atlanta, GA, United States

Editorial on the Research Topic Neurological insights into communication and synchrony between others: what animal and human group communication can tell us

Communication is the cornerstone of human interaction, serving as the conduit through which ideas are exchanged, relationships are formed, and societies thrive. While we often think of communication using overt means, such as physical gestures and speaking to others, the intricacies of communication extend far beyond explicit communication, encompassing non-verbal cues and physiological actions that shape our understanding and interpretation of social interactions ( Phutela, 2015 ; Symons et al., 2016 ). In fact, given the recent advances in artificial intelligence, interpersonal interaction can be extended to occur not between individuals, but instead between individuals and computer, further complicating the role of covert cues. Additionally, recent advancements in neurological research in both animal and human studies have shed light on the underlying mechanisms of non-verbal behavior, offering profound insights into the complexities of human group dynamics and interpersonal communication (e.g., Hirsch et al., 2018 ). Indeed, understanding human communication may require delving into the methods and findings of animal models, as animal models have offered significant insight into human psychopathology ( Heller, 2016 ). Thus, in this Research Topic, we explore the intersection of human, artificial intelligence, and animal research regarding non-verbal communication. We highlight five seminal articles that contribute to our understanding of human communication utilizing diverse tools to understand these phenomena such as metacognition, animal models, and dyadic human interactions.

One article, Neurophysiological and Emotional Influences on Team Communication and Metacognitive Cyber Situational Awareness During a Cyber Engineering Exercise , demonstrates advancements in neurological technology and how they contribute to the understanding of human communication ( Ask et al. ). Researchers examine the realm of cyber operations, where human-to-human communication plays a pivotal role in achieving shared situational awareness for effective decision-making. Utilizing the Orient, Locate, Bridge (OLB) model, researchers investigate the neural correlates of metacognitive cyber situational awareness among cyber cadets. Their findings underscore the influence of neurophysiological and emotional factors on team communication, revealing the importance of vagal tone in shaping metacognitive judgments and mood. This study provides essential insights into the cognitive processes underlying effective communication in cyber defense, and more broadly, to hierarchical communication. Together, these results pave the way for innovative approaches to recruitment, education, and training in this critical domain.

A possible explanation for the relationship between vagal tone and communicative success in cyber operations is emotional state. Functional Graph Contrastive Learning of Hyperscanning EEG Reveals Emotional Contagion Evoked by Stereotype-Based Stressors shows how humans can transmit emotion to one another without being consciously aware ( Huang et al. ). Authors show how emotional contagion pervades dyadic interactions, shaping the dynamics of collaborative tasks and influencing performance outcomes. This article also employed EEG-based hyperscanning to unravel the neural mechanisms underlying emotional contagion in the context of stereotype-based stressors. Through functional graph contrastive learning (fGCL), researchers suggest the impact of emotional contagion on participants' neural activity patterns, revealing its substantial role in modulating performance trajectories. This study contributes valuable insights into the neural underpinnings of emotional dynamics in dyads, enriching our understanding of social interactions in diverse contexts.

Attention to not only one's emotional state, but one's physiological state, can impact communication and interpersonal synchrony, as shown in Autonomic Synchrony Induced by Hyperscanning Interoception During Interpersonal Synchronization Tasks ( Balconi et al. ). This article demonstrates that social interactions are inherently dynamic, characterized by reciprocal influences on emotional states and physiological rhythms. This work investigates the role of autonomic synchrony in dyadic interpersonal synchronization tasks, exploring the impact of interoceptive focus on physiological coherence. By employing hyperscanning techniques, researchers reveal higher synchrony between paired participants in heart rate variability (HRV), skin conductance level (SCL), and heart rate (HR) during tasks involving focused attention on one's own breathing. These findings highlight the interplay between interoception and interpersonal synchrony, offering new avenues for studying psychophysiological coherence in real-time social interactions. This research also shows how human communication and synchrony can be seen not only though explicit communication and neurological activity, but also cardiovascular responses.

Other research takes a more cellular approach, looking at mirror neuron systems (MNS; Bonini, 2017 ), which are essential in understanding the intentions and movements of others. In, Effects of Avatar Shape and Motion on Mirror Neuron System Activity , researchers explored the role of the MNS in perceiving humanness in avatars, shedding light on how avatar characteristics impact neural activity ( Miyamoto et al. ). Application of electroencephalogram (EEG) analysis demonstrated activation of the MNS in response to human-like avatar shapes and motions, highlighting the importance of considering both visual and kinematic cues in avatar design and interpreting the intentions of others through physical movement. These findings offer valuable insights for enhancing inter-avatar communication and fostering a sense of social presence in virtual environments. Further, they demonstrate how understanding human communication in humans is an automatic process that can extend beyond assessing other humans, even down to the neuronal level.

Animal research provides further evidence for the influence of non-verbal communication. In Listening to Your Partner: Serotonin Increases Male Responsiveness to Female Vocal Signals in Mice , researchers explore how the context surrounding vocal communication can significantly influence the perception of vocal signals ( Hood and Hurley ). Specifically, authors examined serotonin's role in modulating behavioral responses to vocal signals in mice. By manipulating serotonin levels systemically and locally in the inferior colliculus (IC), researchers uncover the nuanced effects of serotonin on vocal behavior, highlighting the neurotransmitter's role in modulating male responsiveness to female vocal signals. These findings underscore the importance of considering neurotransmitter systems in understanding the mechanisms of context-dependent communication.

In conclusion, the articles presented in this Research Topic offer a multifaceted exploration of non-verbal communication from neurological perspectives, spanning human and animal research domains. From cyber defense decision-making to avatar design in virtual environments, interpersonal synchrony in social interactions, emotional contagion in dyadic tasks, and autonomic synchrony to serotonergic modulation of vocal perception, these studies illuminate the diverse facets of non-verbal behavior and its underpinnings. By integrating insights from human and animal models, we can deepen our understanding of communication dynamics and pave the way for future advancements in understanding an innate human behavior.

Author contributions

RA: Conceptualization, Writing – original draft. MW: Conceptualization, Writing – review & editing.

The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article.

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Bonini, L. (2017). The extended mirror neuron network: anatomy, origin, and functions. The Neuroscientist 23, 56–67. doi: 10.1177/1073858415626400

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Hirsch, J., Adam Noah, J., Zhang, X., Dravida, S., and Ono, Y. (2018). A cross-brain neural mechanism for human-to-human verbal communication. Soc. Cogn. Affect. Neurosci. 13, 907–920. doi: 10.1093/scan/nsy070

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Keywords: synchrony, human communication, EEG, vocal signaling, non-verbal communication

Citation: Amey RC and Warren MR (2024) Editorial: Neurological insights into communication and synchrony between others: what animal and human group communication can tell us. Front. Hum. Neurosci. 18:1415166. doi: 10.3389/fnhum.2024.1415166

Received: 10 April 2024; Accepted: 15 April 2024; Published: 02 May 2024.

Edited and reviewed by: Lutz Jäncke , University of Zurich, Switzerland

Copyright © 2024 Amey and Warren. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Rachel C. Amey, ramey.ameyc@gmail.com

This article is part of the Research Topic

Neurological Insights into Communication and Synchrony between others: What Animal and Human Group Communication can tell us.

An introduction to multimodal communication

• Original Paper
• Published: 17 July 2013
• Volume 67 , pages 1381–1388, ( 2013 )

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• James P. Higham 1 &
• Eileen A. Hebets 2  

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Though it has long been known that animal communication is complex, recent years have seen growing interest in understanding the extent to which animals give multicomponent signals in multiple modalities, and how the different types of information extracted by receivers are interpreted and integrated in animal decision-making. This interest has culminated in the production of the present special issue on multimodal communication, which features both theoretical and empirical studies from leading researchers in the field. Reviews, comparative analyses, and species-specific empirical studies include manuscripts on taxa as diverse as spiders, primates, birds, lizards, frogs, and humans. The present manuscript serves as both an introduction to this special issue, as well as an introduction to multimodal communication more generally. We discuss the history of the study of complexity in animal communication, issues relating to defining and classifying multimodal signals, and particular issues to consider with multimodal (as opposed to multicomponent unimodal) communication. We go on to discuss the current state of the field, and outline the contributions contained within the issue. We finish by discussing future avenues for research, in particular emphasizing that ‘multimodal’ is more than just ‘bimodal’, and that more integrative frameworks are needed that incorporate more elements of efficacy, such as receiver sensory ecology and the environment.

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Acknowledgments

We are very grateful to Esteban Fernandez-Juricic and two anonymous reviewers for comments on a previous draft of this manuscript. We extend our special thanks to Theo Bakker, James Traniello, and Saskia Hesse for their considerable help with the production of this special issue.

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Higham, J.P., Hebets, E.A. An introduction to multimodal communication. Behav Ecol Sociobiol 67 , 1381–1388 (2013). https://doi.org/10.1007/s00265-013-1590-x

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Call of the wild: the new science of human-animal communication

Degrees in this emerging field offer fascinating research opportunities and career options

I f your pets could speak, what would they tell you? Experts at the animal-computer interaction lab at the Open University (OU) are close to finding out. There, animal behaviour specialists work with designers to create the kind of technology that helps animals communicate and work alongside humans more naturally – to raise the alarm if an owner falls ill, put a wash on, or switch out the lights for an owner who has a disability.

“If you give animals more of a voice, they can make themselves better understood. It’s as though they can talk back to us – and this can be very valuable,” says Clara Mancini, a communication and design expert who founded the lab back in 2011. “We are researching with them, allowing animals to participate in the design process.”

This is a niche area of an already niche field – but dozens of master’s at UK universities relate to animal behaviour in some form; some research-led, some practical.

Working closely with charities, the OU’s lab has collaborated with the likes of Dogs for Good and Medical Detection Dogs. Traditionally, medical detection dogs trained to sniff out cancerous cells have learned to sit down in front of positive samples. But for a dog, this is an unnatural response to an exciting smell, says Mancini, and limits what they can reveal. Her team have created a sort of sniffing platform with pressure pads that measures a dog’s spontaneous response to an odour. Mancini hopes this will allow scientists to detect more nuances in a dog’s reaction, revealing more about the stage or concentration of the cancer, for example. Other projects include designing an alarm – in the shape of a sausage, no less – that an assistance dog could pull if a diabetic owner suffers a hypoglycaemic attack. Researchers have also designed large snout-friendly buttons for assistance dogs in the home.

While the OU’s lab is unique in the UK, the University of Stirling is also offering a master’s in human animal interaction. Many taught courses, such as a new master’s in animal behaviour at the University of St Andrews , aim to act as a springboard into a research career.

Students at Exeter’s MSc in animal behaviour spend a week on Lundy Island observing abundant wildlife, including puffins, guillemots, razorbills and kittiwakes, not to mention the island’s rare breed Soay sheep, says programme director Dr Lisa Leaver, an animal behaviour expert with a background in psychology who founded the course in 2003. “Most of our graduates go on to do PhDs,” she says.

“Some work in science education departments in zoos, or go on to teach, or work with conservation charities.” A research apprenticeship forms a significant part of the course, she says, with subjects as varied as social structure of killer whale groups to male signalling of fiddler crabs on Portuguese beaches.

Understanding animals better has wider moral implications, Mancini believes. “We tend only to listen to our own voice and that’s dangerous. We have forgotten we are part of something bigger – and if we don’t adjust our perspective, we are eventually going to destroy the planet.”

Experience: ‘I measure the bond between animals and humans’

Lauren Samet, 33, is about to complete her PhD in animal welfare and nutrition. Interview by Helena Pozniak

I still pinch myself that I’m here. I’ve always loved animals and wanted to help make a positive change. I’m the first person in my family to go to university. After I graduated in biological sciences from the University of East Anglia , I applied to all the big animal charities – to zoos and to conservation organisations. But animal welfare is so competitive, you need a specialist qualification.

I saved up to take an MSc in animal welfare at Northampton University . It was right up my street, I loved the research element. My supervisor gave me confidence and encouragement to take on a PhD – I never even thought I’d do a master’s, let alone research. During my PhD I’ve worked part-time as a nutritionist for Marwell Zoo for a year on maternity leave cover, which was an amazing experience as those jobs are like gold dust. I’ve also worked as a pet nutritionist in Yorkshire and lectured on an animal science degree.

My research looks at anxiety in dogs and whether herbal supplements actually do have a calming effect. I joined the research team of the Dogs Trust in spring. This is the kind of work I wanted when I first graduated, but I now realise I needed to take the research route to get here. When we are collecting data, we work directly with dogs. Our team is running a groundbreaking longitudinal study looking at dog health, welfare and behaviour. I’m working to develop a tool that measures the bond between humans and animals.

At this level you can carry out research that’s needed to support positive policy changes, as well as having an impact on the welfare of thousands of animals. This is my dream job.

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10.2: Human Language versus Animal Communication

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Human Language versus Animal Communication, from Sarah Harmon

Video Script

part of it. I know a number of you have felt it was difficult throughout this whole process; I’m not going to argue. But when we talk about the actual neural components to language—how the brain processes language—this is where things get really technical.

For this section on animal vs human communication, this is evidence that we have up to this point. It's still evolving and we're still learning, but I can be more confident with what we're saying and what we're presenting here. There is so much that we're still learning about this thing between our ears and how it processes everything, including language, that this is constantly evolving. Just for a frame of reference, I am recording this mid-August of 2021; by the time you watch this, there could be some significant advances, and I won't know it until we get there. Just know that everything I’m presenting is with a grain of salt, in the sense of I am presenting the latest that we have up to this point. There is much more research to come, there is also more research underway and, additionally, our understanding of everything is changing. I'm confident and what I’m going to present for this chapter, but understand that things are changing.

Let's start off with a discussion that we had back in Chapter 1 when we talked about animal communication and human language. Let's refresh our memories a bit; let's go back to those attributes or hallmarks of human language . We understand that human beings have something that is potentially unique, if not very rare, that this form of communication—we talk with arbitrary signs and signals, we talk about things in front of us and not in front of us., we transmit aspects of our culture of our lives, we make an infinite use of finite means, we only have a certain number of vocabulary or lexicon, we only have a certain number of ways that we can put them into a phrase, and yet we can say anything that comes to mind, that we are productive and creative and constantly changing and adapting with our language, we can talk about all these things and ourselves, we can create, we can express and we can talk about things that are not just here in now, not just immediate needs, we go well beyond that. Just think of this class alone!

There are some similar aspects that we see in other forms of animal communication, but limitedly. Let me explain a little bit. There's no question that all animals have some form of communication to express their needs and basic desires; that's not in-argument. The question is: Are they be able to talk about things, not in front of themselves? Are they able to talk about hypotheticals, or make suggestions? Are they able to talk about things that happened in the past, or what may happen in the future?

Maybe. This is why I’m going to say maybe. We know, for example, that most species of birds are able to describe where food or mates are when they're not in front of them—as if to say, “Oh yeah, that flower, that is about five miles that way. That's a really good place to go get nectar.” We know that birds and bees tend to do this, and we see other mammals, especially other primates, have aspects to this in their forms of communication. However, we're still not sure what they actually do among their species.

We are not talking about mimicking human language, and that's a really crucial piece of this argument. We are not talking about when we try to teach a parrot how to talk, or when we try and force another primate to learn a primary sign language. That is not how they communicate with each other, and so we have to abolish that concept entirely.

Because we understand that what a different species used to communicate with its peers is going to be different than what humans do, the research that I’m referring to requires analyzing, observing and being descriptive about what species do amongst their own kind, and to a lesser extent to other animals in the region.

When we talk about animal communication, I love this old The Far Side comic—I'm sorry, I’m a Gen X and The Far Side was part of my upbringing.

It encapsulates everything that we think of about animal communication versus human language, as far as what we say to them versus what they hear and understand. I absolutely love and adore The Far Side , especially this comic but I’ll give you an example in real life. I have a cat her name is Bella and she is 16. When I think about my cat, and I’ve had her since she was a kitten since she was three months old, there's a ton of things that we communicate to each other through voice and through body language. She tells me when she needs attention and love, and when she thinks I need attention and love. She tells me very clearly when she has no food in her bowl or its old food and it's not acceptable anymore. She plays well, not so much anymore, but certainly when she was younger, and she definitely communicates that when I go away, she doesn't like that, and when I come home, she makes that very well known. I communicate to her when she does it behavior that I do not approve of, like if she were to scratch the furniture—which she's never done save for once, and it was to get my attention because I forgot to feed her, so she knows how to get my attention. We have a form of communication. When I am at a low point, she's one of those folks I confide in; I cry and she's there. She cuddles me, and I cuddle her; I tell her all my hopes, fears, desires and wishes. and she purrs.

Now, does she understand what I’m saying? Or, is she like The Far Side comic where she just hears noise and she doesn't know what it is? I don't speak cat and she doesn't speak human, so I don't know what really is able to be communicated as far as displacement, as far as productivity or creativity. We certainly have arbitrary sounds and meanings for those sounds. It has often been said, the cats probably learn to meow because of humans their interactions with humans. When they meow in certain ways, humans do certain activities, and it's a symbiotic relationship. I think there's some of that that's true. But she's not able to tell me her deepest hopes, wishes and desires; she's not able to tell me what she thinks might happen in the future, or what did happen in the past. I don't know what she thinks really, although as I’m saying this, she's walking around my feet right now, because she's clearly telling me she doesn't want me talking like this, she doesn't want the camera and she doesn't want the lights. She wants me on the bed right now; she's able to communicate her needs and basic desires. But not much more. Is that to say that she can do that with a different cat? Who's to say?

Where we have been starting to observe a few pieces with respect to animal communication and whether they might have a language, primarily, has to do with our primate cousins. We know certain things to be true. First of all, their vocal tracks are not like human vocal tracks; they are well more primitive, to the point that they cannot produce the sounds that we can produce. We know that part that goes out the window. Yes, it is true that, certainly for other great apes like chimpanzees and gorillas, some have been taught American Sign Language, in particular, and a few other primary sign languages. But—and this is a huge ‘but’—their learning is very slow and formulaic, and they basically get stuck at the level of a three-year-old. If you remember telegraphic speech from child language acquisition in the previous chapter, they're not able to do much more than that, at least not in ASL. They're also not able to create with ASL very well at all. Therefore, I would argue that you can throw out using any kind of human language with a primate; it's probably not going to work.

All that being said, there is quite a bit of evidence to suggest that they might have something primitive. I’m saying the term ‘primitive’, but I do not want you to think that this is a prescriptive use of it. It's saying that this is a very early stage, and maybe in a millennium or several they might have the capability to use a language, much like a human language. At this stage, we don't know. What do we know is that chimpanzees and other great apes are able to teach each other tools. Chimpanzees are particularly good at this, but even we see this in gorillas and some other great apes. We also know that other primates use sounds to communicate things beyond basic needs and desires, not just a warning system, not just to say, “Hey, I need food” or “Hey, I need sex.” You do observe them using the sounds in more arbitrary ways. But—and this is an incredibly important point—we are still trying to decipher what those calls and sounds mean. When we observe our primate cousins teaching each other how to use tools, they are not necessarily using a vocal communication to do it. There is some kind of gesturing. I don't really want to call a sign language yet, because I think it's too early to say that, but our colleagues and primatologist are showing us that our primate cousins, especially the great apes are able to use some kind of communication that's at a higher level than what most other animals do.

Primates are an interesting discussion. What is also interesting, and this is in the video below is Zipf’s Law, and the video is going to go a little more into that. Here's the interesting thing: It could be that dolphins in particular might have a language. You may have heard of studies on dolphin communication before, and this is an area that continuously evolves. Suffice it to say we are very much at the precipice of understanding what other animals do when they need to talk to each other, when they need to communicate to one another, beyond their basic needs, hopes and desires. We are still learning so much about what our own brains do, let alone what other brains of other animals do. So, we'll come back to this—maybe not in this class, and maybe not in the next year, but certainly in the future, so keep an eye on this.

10.1.2 More on Zipf's Law, from NOVA Wonders (PBS)

To finish things off, watch the video below about Zipf's Law, and why we still have so much more to learn about other animals and their methods of communication. (The video is captioned.)

Will we ever be able to have a conversation with animals?

L ast December, the Whale SETI scientific team had a 20-minute conversation with a humpback whale. The experiment, which took place on the Alaskan coast, entailed reproducing sounds made by a whale attempting to make contact, through an underwater loudspeaker. The University of California Davis’ Dr. Brenda McCowan, lead author of the study, stated that this was the “first communicative exchange between humans and humpback whales in humpback ‘language.’” Or as Finding Nemo ’s Dory would put it, it is the first time that humans have managed to “speak whale.”

The arrival of artificial intelligence (AI) and machine learning have set expectations on their head when it comes to achieving complex communication with other species . These technologies allow experts to analyze animals’ sounds, movements and behaviors with a speed and precision that would be impossible for unassisted humans. In the Whale SETI team’s study, for example, this technology was essential to be able to decode and reproduce the whales’ calls. They used advanced equipment to listen and analyze recordings of the animals’ sounds, which helped scientists to detect patterns and variations in their communication, as well as variations in the tone of their calls and in the way they produce sounds.

Kate Armstrong, director of the Interspecies Internet program, is convinced that in the future, we will be able to decode and understand the language of various animal species with a high level of precision. “In a certain sense, we’re already doing it,” she explains on a videocall, pointing out that one of the great challenges in the compilation of data for communication with other species is the presence of noise. “That’s why most of the studies that have been reported on by the media have been done on species who live underwater, where it is easier to extract data,” she says. “This technological advancement brings with it the need to think carefully about how we use these tools and consider implementing regulations to ensure ethical and responsible use.”

The world’s limits

Speaking with an animal using their own language has certain limitations. For example, the recent interaction with the humpback whale was not a conversation in the human sense. That is to say, there was no exchange of ideas or complex meaning. Instead, it was an exchange of sounds that showed that whales can respond in an intelligent and adaptive manner to auditory signals. Researchers interpreted this as proof that whales can participate in a kind of “dialogue” using their own system of audio communication. “Although we can decode their sounds or gestures, differences in cognition and behavior between humans and other species can limit the depth and kind of communication possible,” says Armstrong.

Linguist Mamen Hornos questions “if it is really possible to translate thought between species.” Hornos argues that, even if we share some experiences of reality with other animals, like cause-effect relationships and spatial orientation, we don’t know if they can understand profound human ideas. “And there could also be important things for animals that we don’t understand.”

Hornos mentions philosopher Ludwig Wittgenstein’s famous aphorism: “The limits of my language are the limits of my world.” This idea suggests that our way of seeing and understanding the world is closely connected to our language. When it comes to human-animal communication, each species may be limited by its own linguistic and conceptual perception of the world. Interspecies communication might never be completely symmetrical or complete, since each species perceives and understands the world through its own linguistic and cognitive “lens.”

The limits of language

Before anyone believed that it was possible to decode the language of whales, there were scientists who conducted famous experiments in an attempt at teaching human language to animals. For example, in 1966, only three years after the novel Planet of the Apes came out, two researchers named Allen and Beatrix Gardner adopted a chimpanzee named Washoe in order to investigate the linguistic capabilities of primates. They treated her as if she were a human child and taught her how to communicate using American Sign Language, a method of communication used by Deaf people. Washoe learned more than 350 signs and could use them to form simple phrases and express ideas of some complexity.

In another case in 1977, a researcher named Irene Pepperberg worked with a parrot named Alex. She taught him more than 100 words and Alex learned to recognize shapes, materials and numbers. He even invented a new way to say “apple,” because the original word was hard for him to pronounce with his beak, which is designed for cracking nuts and seeds. Dr. Pepperberg later recalled that he last words Alex said to her before he died in his cage were, “You be good. I love you. See you tomorrow.”

J.M. Mulet, scientific researcher and author, says that, even though there have been “very optimistic” studies at certain points that announced that their researchers had achieved complex communication with animals, these ultimately did not convince language experts. He cites the case of the gorilla Koko, who was trained by psychologist Francine Patterson. It was said that Koko had learned more than 1,000 words in sign language and could carry on conversations. But Mulet doubts that Koko really understood that she was using a new language.

In a passage in which he examines similar work done with other primates, Mulet writes, “It would not be normal, if a chimpanzee was aware of knowing a new communication system, for it not to try to teach it to other chimpanzees, or ask any questions.” In fact, there’s no proof that any non-human animal has asked a question in the sense that humans understand and use questions. Asking questions does not just entail the use of a symbolic language: it also requires self-awareness and the understanding of concepts that are more complex than the communication of basic needs. “The chimpanzee only uses this language when their human instructor directs it at him. For him, it is not communication, but rather, a game,” says the expert.

For Hornos, what keeps an animal of superior intelligence, like some primates, from being able to use human language in the same way that we do, is that they don’t have a hierarchical understanding of language, but rather a linear one. To understand this, think of the phrase “the cat eats fish.” In linear processing, we would understand this sentence by simply reading it word by word, in order: “The,” “cat,” “eats,” “fish.” Each word is understood individually, one after the other. Now, in hierarchical processing, we analyze how the terms are grouped and related. “The cat” is the subject and “eats fish” is the predicate. In this view, we see not only individual words, but also how they relate to each other: the subject “the cat” performs the action of “eating” the object “fish.” Thus, while linear processing sees words one after another, hierarchical processing sees more complex relationships and structures between groups of words.

“There is a hierarchical structure in human language that animals do not have,” explains Hornos. “Animals understand signs and symbols, but they do not have the capacity to understand the syntactic structure and more complex implications of language.”

However, some scientists argue that, given that humans evolved from ancestors that they have in common with other species, there should be a certain continuity or evolutionary relationship between our communication systems and those of other species. Hornos says that the evolution of language doesn’t have to be a linear or progressive process. “Evolution is not always gradual. Similar to life itself, which has significant moments that change us, when it comes to evolution, important leaps also take place,” she says.

Will our relationship with animals change?

Armstrong holds that one of the most significant goals of the Interspecies Internet project is that a better comprehension of the language of animals will increase our empathy towards them. “Understanding the language of endangered species can give us valuable information when it comes to their conservation. For example, knowing what animals communicate about their threats or mating needs can help conservationists make better informed decisions when it comes to protecting habitats and species.” According to the expert, as we better understand how animals communicate, we may come to recognize and value their intelligence and cognitive abilities more highly, and change the way we view and treat them legally and socially.

According to Marta Amat Grau, a PhD in veterinary medicine who is head of the ethology service at the Autonomous University of Barcelona’s faculty of veterinary medicine, progress in the understanding of animal language and communication is positively influencing our relationship with pets. Grau explains that “many behavioral problems stem from a lack of understanding of how we communicate with dogs and cats.”

“Today, we have ample knowledge to interpret, for example, a cat’s meows or a dog’s barks, especially when we analyze them in conjuncture with their body language, which can indicate whether they are experiencing anxiety or seeking attention,” she explains. She also mentions that in recent years, apps have appeared that are designed to translate the sounds or behaviors of pets into a language more understandable to humans. However, she warns that most of these apps have no scientific backing.

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Animal behavior research is getting better at keeping observer bias from sneaking in – but there’s still room to improve

Professor and Associate Head of Psychology, University of Tennessee

Disclosure statement

Todd M. Freeberg does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

University of Tennessee provides funding as a member of The Conversation US.

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Animal behavior research relies on careful observation of animals. Researchers might spend months in a jungle habitat watching tropical birds mate and raise their young. They might track the rates of physical contact in cattle herds of different densities. Or they could record the sounds whales make as they migrate through the ocean.

Animal behavior research can provide fundamental insights into the natural processes that affect ecosystems around the globe, as well as into our own human minds and behavior.

I study animal behavior – and also the research reported by scientists in my field. One of the challenges of this kind of science is making sure our own assumptions don’t influence what we think we see in animal subjects. Like all people, how scientists see the world is shaped by biases and expectations, which can affect how data is recorded and reported. For instance, scientists who live in a society with strict gender roles for women and men might interpret things they see animals doing as reflecting those same divisions .

The scientific process corrects for such mistakes over time, but scientists have quicker methods at their disposal to minimize potential observer bias. Animal behavior scientists haven’t always used these methods – but that’s changing. A new study confirms that, over the past decade, studies increasingly adhere to the rigorous best practices that can minimize potential biases in animal behavior research.

Biases and self-fulfilling prophecies

A German horse named Clever Hans is widely known in the history of animal behavior as a classic example of unconscious bias leading to a false result.

Around the turn of the 20th century , Clever Hans was purported to be able to do math. For example, in response to his owner’s prompt “3 + 5,” Clever Hans would tap his hoof eight times. His owner would then reward him with his favorite vegetables. Initial observers reported that the horse’s abilities were legitimate and that his owner was not being deceptive.

However, careful analysis by a young scientist named Oskar Pfungst revealed that if the horse could not see his owner, he couldn’t answer correctly. So while Clever Hans was not good at math, he was incredibly good at observing his owner’s subtle and unconscious cues that gave the math answers away.

In the 1960s, researchers asked human study participants to code the learning ability of rats. Participants were told their rats had been artificially selected over many generations to be either “bright” or “dull” learners. Over several weeks, the participants ran their rats through eight different learning experiments.

In seven out of the eight experiments , the human participants ranked the “bright” rats as being better learners than the “dull” rats when, in reality, the researchers had randomly picked rats from their breeding colony. Bias led the human participants to see what they thought they should see.

Eliminating bias

Given the clear potential for human biases to skew scientific results, textbooks on animal behavior research methods from the 1980s onward have implored researchers to verify their work using at least one of two commonsense methods.

One is making sure the researcher observing the behavior does not know if the subject comes from one study group or the other. For example, a researcher would measure a cricket’s behavior without knowing if it came from the experimental or control group.

The other best practice is utilizing a second researcher, who has fresh eyes and no knowledge of the data, to observe the behavior and code the data. For example, while analyzing a video file, I count chickadees taking seeds from a feeder 15 times. Later, a second independent observer counts the same number.

Yet these methods to minimize possible biases are often not employed by researchers in animal behavior, perhaps because these best practices take more time and effort.

In 2012, my colleagues and I reviewed nearly 1,000 articles published in five leading animal behavior journals between 1970 and 2010 to see how many reported these methods to minimize potential bias. Less than 10% did so. By contrast, the journal Infancy, which focuses on human infant behavior, was far more rigorous: Over 80% of its articles reported using methods to avoid bias.

It’s a problem not just confined to my field. A 2015 review of published articles in the life sciences found that blind protocols are uncommon . It also found that studies using blind methods detected smaller differences between the key groups being observed compared to studies that didn’t use blind methods, suggesting potential biases led to more notable results.

In the years after we published our article, it was cited regularly and we wondered if there had been any improvement in the field. So, we recently reviewed 40 articles from each of the same five journals for the year 2020.

We found the rate of papers that reported controlling for bias improved in all five journals , from under 10% in our 2012 article to just over 50% in our new review. These rates of reporting still lag behind the journal Infancy, however, which was 95% in 2020.

All in all, things are looking up, but the animal behavior field can still do better. Practically, with increasingly more portable and affordable audio and video recording technology, it’s getting easier to carry out methods that minimize potential biases. The more the field of animal behavior sticks with these best practices, the stronger the foundation of knowledge and public trust in this science will become.

• Animal behavior
• Research methods
• Research bias
• STEEHM new research

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