In many, many ways, fish of the species Brienomyrus brachyistius do not speak at all like Barack Obama. For starters, they communicate not through a spoken language but through electrical pulses booped out by specialized organs found near the tail. Their vocabulary is also quite unpresidentially poor, with each individual capable of producing just one electric wave—a unique but monotonous signal. “It’s even simpler than Morse code,” Bruce Carlson, a biologist at Washington University in St. Louis who studies Brienomyrus fish, told me.
In at least one significant way, though, fish of the species Brienomyrus brachyistius do speak a little bit like Barack Obama. When they want to send an important message …
They stop, just for a moment.
Those gaps tend to occur in very particular patterns, right before fishy phrases and sentences with “high-information content” about property, say, or courtship, Carlson said. Electric fish have, like the former president, mastered the art of the dramatic pause—a rhetorical trick that can help listeners cue in more strongly to what speakers have to say next, Carlson and his colleagues report in a study published today in Current Biology.
“Fish can’t yell,” Kate Allen, a neuroscientist at Johns Hopkins University who wasn’t involved in the study, told me. But titrating the amount of time that passes between the signals they send might be the next best thing. (Brienomyrus, she said, seems to be deploying a version of the polarizing “emphasis clap” that’s found its way into so many tweets.)
These pauses might be especially useful for fish with such a limited repertoire of oratory tools. Each individual fish says just one word—its own signature electric wave, as distinctive as the way a person says their name: Barack. That voiciness alone can reveal the speaker’s age, sex, or even social status. But one special wave is all a fish gets, and it looks roughly the same every time: Barack Barack Barack. (A Barack fish cannot, sadly, even say Michelle.) To communicate a more context-dependent message, such as “Get away from me” or “Let’s mate,” fish have to tinker with the frequency at which the waves pulse out: Barack---Barack--BarackBarack--Barack---Barack says something different than Barack----Barack--Barack-BarackBarackBarackBarack. It’s pretty typical for several Baracks to cluster together in rapid succession; the fish can’t speak in phrases or sentences, per se, but these wildly intricate trains come pretty close.
You can listen here to get a sense of these patterns, which have been passed into an audio speaker:
From the listener’s perspective, the onslaught of Baracks means receiving and processing the exact same signal over and over and over. A few years ago, Tsunehiko Kohashi, then a postdoctoral fellow in Carlson’s lab, was sifting through old data when he noticed that this glut of identical electric waves seemed to be exhausting the listener’s brain cells. When these cells operate at full capacity, they’ll spark out a “message-received” signal (!!!!!) upon registering an inbound wave. But the longer the cells are stimulated with the same signals, the less enthusiastic their responses become (!!). The weary cells, Kohashi soon discovered, need a sensory palate cleanser—a pause of about a second or more—to recover and reset. “That allows the animal to better understand and interpret the signal,” Kory Evans, a fish biologist at Rice University who wasn’t involved in the study, told me.
Kohashi and his colleagues decided to confirm the findings by observing a fresh batch of live laboratory fish. They set up pairs of animals in adjacent tanks and linked the watery chambers with electrodes so that the fish could discourse. Then, they selectively muted segments of each fish’s speech for two seconds apiece. The team found that when speaker fish spewed signals at a blistering rate, the listeners’ noggins quickly zonked out. A carefully placed pause, however, whipped their brains back into shape—and prompted the listeners to send out their own burst of electric signals in return (MichelleMichelleMichelle), a sort of “Okay, okay, you’ve got my attention” response.
Fish intentions are difficult to assess. (The electric fish did not respond intelligibly to requests for comment.) But the Brienomyrus species does seem to be actively punctuating its conversations with pauses, the team found—the piscine equivalent of “on purpose.” When the researchers pasted electrodes onto fish tanks to record the conversations within, they found that the animals paused more frequently while cohabiting with a roommate than when they were housed alone. The positions of the pauses also seemed to precede big bursts of speech—signals that Carlson suspects were helping fish court each other, or stake out a piece of real estate. A pause, he said, is a message in and of itself, a silent way of saying “It’s time to take me seriously.”
Plugging a pause into human language is, for the most part, pretty trivial—a matter of taking a breath or a beat, or a keystroke or two that slightly lengthens a page. Short silences pepper monologues and dialogues, even in writing (hello, em dashes, semicolons, ellipses). But for an electric fish, the difference between
can be much more fraught.
Electric fish use signals to interact not just with one another but with the watery world around them. The waves they produce help them sense their surroundings, a process called electrolocation. To maintain their bearings, fish will hum out signals almost constantly; when they pause, “it’s like they’re closing their eyes for a period of time,” Allen, of Johns Hopkins, told me. Verbal hiatuses, so to speak, don’t happen willy-nilly.
Scientists have long known that electric fish that lose fights will deliberately go mum for many seconds at a time and slink away in silence, like an attempt to evade detection by their electrically sensitive rivals. The findings from Carlson’s team represent a new kind of pause—a shorter one that can keep a dialogue going, rather than grind it to a halt. “This is a pause that’s attention-grabbing,” Sophie Picq, an electric-fish biologist at Michigan State University who wasn’t involved in the study, told me.
Humans have yet to fully crack the fish’s electric code. Still unclear are the contexts in which Brienomyrus most often uses pauses, or how these conversational gaps shake out when animals are gabbing in groups. Researchers also can’t be certain how deep the parallels between fish and human go. Among people, pauses can be moving and memorable. They create contrast between signal and noise; they capture focus and build anticipation—the perfect strategy for a politician teeing up sound bites. When people hear pauses, studies have shown, they better internalize the information that comes next. But pauses can also reflect nervousness or confusion, or an utter lack of knowledge—the manifestation of a person who’s desperately grasping for words. Pauses can be ambiguous or manipulative, leaving the listener on tenterhooks. They can … perhaps … be—much like adverbs, adjectives, and florid language—really, truly, egregiously overused; no one wants to wait forever for a simple statement, conveying a single and uncomplicated idea, to just come to a close.
It’s hard to imagine an electric fish cavorting with this much complexity. But years of research have taught Kohashi that Brienomyrus is a lot more human than some might like to think. When the fish communicate, whether through pulses or body language, they’re constantly asserting themselves. (Electric animals are, unsurprisingly, keen on showing one another who’s in charge.) Kohashi has seen fish be selfish and arrogant. He’s seen fish be bullied, and get downright depressed. The fish clearly make one another feel. “Some fish are,” he said, pausing, “assholes.”
But Kohashi thinks the fish have plenty to teach us about decorum as well, and the importance of hitting the reset button from time to time. (Since performing these experiments, he thinks he’s become a better public speaker.) The babble of Brienomyrus also delightfully claps back against the common misconception that fish are just “simple-minded creatures that blub about in bowls,” Evans, of Rice, told me. “They’re far more complex than we give them credit for.”