How Would We Know If We're Talking to Aliens?

A follow-up to my review of Xenolinguistics.

Suppose we encounter aliens and begin linguistic fieldwork in earnest. Or, suppose that we have reason to believe we may have finally successfully decoded a language of cetaceans or cephalopods (who for all practical purposes in this context may as well be aliens, despite living with us on Earth). How would we be able to tell that we actually got it right--that we understand what they mean, and that they understand what we mean? In particular, how would we overcome the Clever Hans Effect?

Language is ultimately a noisy and lossy channel; a great deal of human communication involves the receiver inferring what the sender probably meant, not directly extracting information that is unambiguously encoded in the linguistic signal itself. And even among humans, this can frequently go wrong, resulting is misinterpretations. But at least living humans can object when they are misinterpreted, and try to correct the miscommunication. That is much, much harder for nonhumans with whom we do not already share a language--and for dead or otherwise unavailable humans who have left behind undeciphered documents.

In these situations, it is all too easy to impute meaning from our own minds onto signals that arise from a totally different intent, or have no meaning at all. And if we're only reading out the information that we unintentionally inserted ourselves, we're not really communicating, are we?

So, there need to be ways to validate our decipherments--ways to obtain information from a non-human entity that we know we could not have provided ourselves. One option, which has been used with human texts, is to hold out validation data; if you can decipher the hieroglyphics on the Rosetta Stone without reference to anything but the Rosetta Stone, and then the system you derived turns out to produce sensible-looking results for other collections of hieroglyphics, then you've probably got it right. If you claim to have deciphered the entire Voynich Manuscript, big deal, it's only the 10th claim this year; but if you claim to have deciphered a few pages in isolation, and other people can use your system to make sense of the rest of it, that would be a much stronger claim.

Theoretically, this could be done with aliens as well. We have, as a species, collected quite a lot of recordings of whale song that could serve as validation data, for example. But it does require special circumstances to be able to collect that data. For example, if we find some technologically-primitive tribe in an alien rainforest (or even an Earthly rainforest for that matter), who do not have written records to reference, would we be terribly surprised if they objected to us setting up equipment to record everything they say just so we can analyze it later? It would be much better to have access to interactive methods, even though interaction itself increases the risk of Clever Hans events.

Another option is to attempt to make predictions about the real world based on alien-sourced data--but this also requires special circumstances, insofar as you must find a subject area which humans do not already know about, but can verify. For example, we haven't explored much of the ocean, but we have the ability to dive to specific places in the ocean if it's worth it. So, if someone claims that a whale or a squid gave them the location of a shipwreck, and then we go and find that shipwreck, that's good evidence that they can really communicate. Another option would be checking on solutions to mathematical problems--but, of course, that only works if the aliens have mathematics, and are more advanced than us in at least one area. "We don't know how to answer that." is sadly both a perfectly reasonable true response, and extremely easy to fake. Additionally, even when they exist, those kinds of natural situations can get expensive to investigate. 

The obvious alternative is to manufacture such situations. Place the alien in a test environment hidden from the human communicator. Allow the human communicator access to the alien, such that the alien is their only source of information about the test environment. See if they can describe it accurately afterwards. If a human can extract information that is verifiably available through no means other than communication with an alien, then we can be confident in the decipherment scheme used for such communication.

Of course, this does require a certain degree of cooperation from the alien! Ultimately, establishing verifiably accurate communication with an alien species depends largely on the motivation that they have for communicating with us, and their ability to understand our desires prior to establishing linguistic communication. Also note that verifying that we have deciphered a language is entirely different from verifying that an alien species has language. There are observational experiments that can rule out any option other than individuals communicating arbitrary information with each other in an open-ended system, such as observing dolphins executing coordinated swim routines together that they have never done before, and so could not have learned from observation. One instance of that type could be attributed to a limited-usage para-linguistic system, but many observations of individuals acting on information they could only have obtained by communication with another individual allows eventually building up a strong case for the existence of language in an alien species, even if we have no idea how it works.

One significant point brought up in the Xenolinguistics book is that we do not currently have the fieldwork techniques that would be necessary for reliably deciphering and documenting alien languages. Creating protocols for identifying the existence of languages to high degree of certainty is one of those gaps--when we do fieldwork with humans, we can assume with a high degree of certainty that they do use language, and we merely need to figure out their particular language. But if you encountered a bunch of electroceptive alien fish, would it even cross your mind that they might have language and might be worth talking to? But another significant gap is precisely in creating those protocols to validate that our understanding is correct. When working with other humans, there is a huge amount of shared context and instinctual knowledge that we can use to guide our investigation--you don't have to speak another person's language to understand the significance of deictic pointing, or to realize when they are upset or happy. But when it comes to non-human creatures (particularly those, unlike dogs, whom we have not already bred to share understandable signals with us; and unlike cats, whom we have spent enough time with to have some understanding of their desires and body language), all of that goes out the window, and we have to start from a place of no assumptions, and rigorous scientific validation of every conclusion if we are to avoid misunderstanding and misleading ourselves. If you're looking for more ways to incorporate linguistics into science fiction, here you go: propose the missing protocols!

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