The “alien language” experiment

Play the online game, see the growing tree!

Recently, we have been trying to discover where language structure comes from by building miniature “alien” languages in the lab and watching how they evolve as they are passed on from one learner to the next. This page gives some background of these experiments, featured on the BBC programme Horizon.

Language allows us to understand utterances we have never heard before, because we can take sentences and decompose them into recombinable parts (like words and phrases). This makes language uniquely powerful and means that language structure looks as if it has been “designed” for communication.

Normally, to explain the origins of design in nature, we appeal to Darwinian natural selection. This has lead many to believe that humans evolved to have language structure encoded in our genes. In particular, that our brains have adapted to be good at learning language.

We propose an alternative approach: language has adapted to be good at being learned by us. This can happen because language evolves culturally through being repeatedly learned and used by generations of individuals. This is the process we aim to recreate in the laboratory, having previously demonstrated how it works in computer simulations.

We create a miniature artificial language involving random strings of syllables paired with alien fruit pictures. A volunteer tries to learn this language, and then we test them by asking them to produce what the alien would have said for each picture. They find this task very hard, precisely because the language has no structure.

However, we want to see how language evolves, not just how it is learned, so we have designed a kind of “Chinese Whispers” (a.k.a. “Telephone”) game but using whole languages. Put simply, we give the second volunteer in the lab the language that the first person produced to learn from. After this, the third person learns from the second and so on.

The remarkable thing that happens is that, even though people are simply trying to give us back exactly the language we trained them on, the language evolves. Over a few “generations” of participants in our experiment, the language gets easier and easier to learn. Eventually, the participants can even understand perfectly the alien sentences for fruit pictures they have never seen before.

Language, because it is culturally transmitted, is an evolutionary system in its own right. Many of the adaptive features of linguistic structure arise from this process rather than having to be encoded specifically in our genes. Of course, the human brain provides the essential scaffolding for the cultural evolution of language in the first place, but it need not specify all the details innately.

For more information, you can read one of our original research papers.

You can also play an early version of an online cultural evolution experiment game relating to this work, and see the results of the ongoing evolving culture.