Summary: From the flashing of fireflies to the chirping of crickets and the beats of modern pop music, much of the natural world seems to be vibrating to the same rhythm.<\/p>\n
A new study reveals that communication signals across wildly different species tend to repeat at a nearly universal tempo of 2 hertz (two beats per second). Researchers suggest this isn\u2019t a coincidence, but a biological \u201cresonance\u201d where animal brains are naturally tuned to process information most efficiently at this specific pace.<\/p>\n
Key FactsBody Size Doesn\u2019t Matter: The 2Hz rule applies to tiny insects and large mammals alike, suggesting the constraint is in the nervous system, not the physical size of the animal.Biomechanical Overdrive: Animals can signal faster, panicked fireflies flicker at much higher rates, but they choose 2Hz for social communication because it\u2019s easier for the receiver to understand.The \u201cTaylor Swift\u201d Constant: Most popular music clusters around 120 beats per minute (BPM), which is exactly 2 hertz. This matches the human walking pace and the natural \u201ccadence\u201d of our speech.Computational Proof: Computer models of neural circuits confirmed they respond most strongly to signals within this narrow 0.5 to 4 hertz band.<\/p>\n
Source: Northwestern University<\/p>\n
Animal communication can look wildly different \u2014 flashing lights, chirping calls, croaking songs and elaborate dances. But new research from Northwestern University suggests many of these signals share a surprising feature: They repeat at nearly the same tempo.<\/p>\n
In a new study, Northwestern scientists found that communication signals across a wide range of species tend to repeat at about 2 hertz, or roughly two beats per second.<\/p>\n
The researchers propose this tempo might reflect a shared biological constraint. Animal brains, including humans, may be naturally tuned to process signals arriving at that pace. In other words, two beats per second may be a rhythmic \u201csweet spot\u201d that enables brains to detect signals more easily and process communication more efficiently.<\/p>\n
Understanding this potentially universal tempo could help scientists better interpret animal signaling and social behavior across species. The findings also hint that human perception of rhythms, including beats in popular music and the cadence of speech, may arise from the same neural timing principles found throughout nature.<\/p>\n
The\u00a0study was published today\u00a0(April 14) on in the journal\u00a0PLOS Biology.<\/p>\n
\u201cThere seems to be an abundance of organisms signaling or communicating at a relatively narrow band of tempos,\u201d said Northwestern\u2019s Guy Amichay, who led the study.<\/p>\n
\u201cThey all seem to stay around 2 or maybe 3 hertz. In principle, they could communicate at other rhythms. Physically, there is nothing preventing them from communicating at, say, 10 hertz, yet they do not.<\/p>\n
\u201cTo explain this phenomenon, we propose that this tempo of 2 hertz might be easier to understand because it resonates with your brain. It resonates with the human brain, firefly brain, sea lion brain, frog brain and so on.\u201d<\/p>\n
\u201cThere\u2019s a somewhat subtle point here: we suspect that getting the \u2018carrier\u2019 signal in the right tempo range is key to communicating efficiently,\u201d said Northwestern\u2019s\u00a0Daniel M. Abrams, the study\u2019s senior author.<\/p>\n
\u201cIt might not be that the tempo itself conveys any information, but it just serves as a baseline for getting attention, with actual content sent on top of it like musical notes following along with the beat in a song.\u201d<\/p>\n
Amichay is a research associate in Abrams\u2019 laboratory at Northwestern. An expert on synchronization and pattern formation, Abrams is a professor of engineering sciences and applied mathematics at Northwestern\u2019s\u00a0McCormick School of Engineering\u00a0and co-director of the\u00a0Northwestern Institute on Complex Systems\u00a0(NICO), as well as a member of the\u00a0National Institute for Theory and Mathematics in Biology\u00a0(NITMB). Amichay and Abrams co-authored the study with\u00a0Vijay Balasubramanian, the Cathy and Marc Lasry Professor of Physics at the University of Pennsylvania.<\/p>\n
Interactions between light and sound<\/p>\n
The study grew out of Amichay\u2019s project to understand how synchrony arises in nature. Along with some lab mates, Amichay visited Thailand to collect footage of firefly swarms, blinking together in the countryside. As he gazed at the fireflies for hours, Amichay could not help but notice an uncanny coincidence.<\/p>\n
\u201cAt some point, I thought that the flashing of the fireflies and the chirping of the nearby crickets were in sync with each other,\u201d Amichay said. \u201cMy colleagues noticed it too, and we thought that it was crazy that these two unrelated species would interact in such a way.\u201d<\/p>\n
After analyzing their own recordings, the team concluded that the species were not synchronizing with one another. Instead, they were sending independent signals at very similar tempos \u2014 around two-to-three pulses per second.\u00a0<\/p>\n
To investigate whether the firefly-cricket coincidence reflected a broader pattern, Amichay and Abrams analyzed previously published studies of animal communication across a wide range of species. These rhythmic signals included: firefly flashes, cricket chirps, frog calls, birds\u2019 mating displays, sound and light pulses from fish and vocals and gestures from mammals.<\/p>\n
Despite enormous differences in body sizes, habitats and communication methods, the team found that many species repeat signals within a narrow range of roughly 0.5 to 4 hertz (1 to 4 beats per second). The pattern spans animals that communicate through sound, light or movement, suggesting a common underlying principle.<\/p>\n
\u201cIf you try to catch a firefly, it panics and flickers much faster,\u201d Amichay said. \u201cBiomechanically, they are able to signal faster. So, we wondered if there might be a deeper reason why very different systems signal at this tempo and not any other tempo.\u201d<\/p>\n
From crickets to concerts<\/p>\n
As Amichay and Abrams searched for a hidden principle, they happened to meet Balasubramanian, who studies neuroscience and theoretical physics, at an NITMB conference. Balasubramanian noted that the biophysics of a single neuron operates at the same rhythm.<\/p>\n
Neurons require time to integrate information before firing again. Because of this biological constraint, neural circuits tend to respond most strongly to signals arriving every few hundred milliseconds \u2014 roughly two times per second.<\/p>\n
To test this idea, the team built computer models of simple neural circuits and examined how they responded to signals at different tempos. According to the models, the circuits respond most strongly to signals within the same 2 hertz range observed across animal communication. That means communication signals may have evolved to match the rhythms that brains process most easily.<\/p>\n
According to Amichay, musicologists have long noted that popular songs cluster around 120 beats per minute, which is exactly 2 hertz.<\/p>\n
\u201cThat rhythm fits our body; it fits our limbs,\u201d he said. \u201cWe walk roughly at 2 hertz, so it\u2019s easy for us to dance to music that\u2019s 2 hertz. Of course, more experimental music can have drastically different beats. But if you turn on the radio and hear Taylor Swift \u2014 that\u2019s often 2 hertz.\u201d<\/p>\n
Amichay said he hopes the study inspires other researchers to examine a broader range of species and directly measure how brains respond to different communication rhythms.<\/p>\n
Those efforts could reveal whether this potentially universal tempo is a fundamental feature of neural systems and possibly lead to new insights into how it influences behavior across species.<\/p>\n
\u201cIt\u2019s tempting to think there\u2019s a deeper connection here \u2014 that maybe we\u2019re all on the same shared wavelength,\u201d Amichay said. \u201cBut we\u2019re still exploring what this might mean.\u201d<\/p>\n
Funding: The study, \u201cA universal animal communication tempo resonates with the receiver\u2019s brain,\u201d was supported by NICO, the Buffett Institute for Global Affairs and the National Institute for Theory and Mathematics in Biology.<\/p>\n
Key Questions Answered:Q: Does this mean animals are actually \u201cdancing\u201d to the same beat as us?<\/p>\n
A: In a biological sense, yes! While a cricket isn\u2019t \u201clistening\u201d to the radio, its brain is built to find 2Hz signals easy to process, just like ours. We find 120 BPM music \u201ccatchy\u201d because it resonates with the fundamental timing of our neurons.<\/p>\n
Q: If 2Hz is so efficient, why don\u2019t we talk that fast all the time?<\/p>\n
A: We actually do come close! The \u201ccadence\u201d or rhythm of human speech often falls into this 2-3Hz range. We use it as a skeleton to hang our words on, making it easier for the listener\u2019s brain to stay \u201clocked in\u201d to what we are saying.<\/p>\n
Q: Could this help us talk to animals?<\/p>\n
A: It gives us a \u201cfrequency\u201d to start with. If we want to get an animal\u2019s attention\u2014whether it\u2019s a dog or a swarm of bees, sending a signal at 2Hz is essentially \u201cknocking on the door\u201d of their brain in a way they are evolutionarily primed to answer.<\/p>\n
Editorial Notes:This article was edited by a Neuroscience News editor.Journal paper reviewed in full.Additional context added by our staff.About this neuroscience research news<\/p>\n
Author:\u00a0Amanda Morris<\/a>
Source:\u00a0Northwestern University<\/a>
Contact:\u00a0Amanda Morris \u2013 Northwestern University
Image:\u00a0The image is credited to Neuroscience News<\/p>\n