Alien communication may be washing over the Earth this very moment. The trouble is, we may not be able to separate their message from the rest of all the noise coming out of the cosmos.
But we may soon get some help by studying a surprising species: dolphins.
A new study published in the journal Animal Cognition, found that bottlenose dolphins "speak" to each other while solving problems. And the dolphins in the study weren't just saying "hi" as they worked, but were discussing their cooperation on the task.
The two bottlenose dolphins studied were given a canister that encouraged cooperation to open it. Although cracking it open solo was possible, it was designed to be much more challenging. The dolphins made more vocalizations (burst pulses) while opening the can together than while working alone, suggesting their success came in part from chatting.
And, as it turns out, learning about dolphin language could also be a huge help in the Search for Extraterrestrial Intelligence (SETI).
Dolphin communication adheres to a rough linguistic rule that unites human languages, called Zipf's law, and could be a sign that "dolphinese" is our species' first brush with a complex language that's not one of ours.
Named for linguist George Zipf, the law states that the frequency of a language's common words follow a logarithmic trend — the most common word in a language appears twice as often as the second most common word, and the most common appears three times as often as the third, and so on for the entire language's vocabulary.
The graph below shows how Zipf's law applies to a sampling of world languages. The line's slope (steepness) averages out to about -1. If we spoke a random selection of words without meaning, this frequency line would have a slope of 0, as all the meaningless words have an equal chance of occurring.
Dolphin "language," it seems, fits neatly into this graph.
In a 2011 study, SETI researchers observed the speech from infancy to adulthood of dolphins, and found that their "word" frequency graph had a slope of -0.95. By comparison, squirrel monkeys' grammatically random communication had a slope of -0.06, and chemically-emmitted communication used by cotton plants had a slope of -1.6 — not random, but too redundant for language.
Zipf's law isn't a perfect test of language complexity, but it does show that "dolphinese" may exhibit some of the grammatical rules and forms we call syntax, one of the foundations of language.
Observing complex, non-human "languages" could be a huge help in deciphering alien messages, mainly because we're so used to Earth languages. If an alien species managed to send an intelligent greeting to Earth, we may not be able to discern it from noise or static.
But if we consider that the carefree-seeming squeaks and whistles of dolphins might actually make up a complex, nuanced language, we may be better equipped to decipher something even stranger — like messages from an alien world.
