What makes human communication so special?

Vienna, January 31, 2021 -- Human expression is open-ended, versatile and diverse, ranging from ordinary language use to painting, from exaggerated displays of affection to micro-movements that aid coordination. In their new research "Expression unleashed: The evolutionary & cognitive foundations of human communication", published online as a preprint ready for external commentary by Cambridge University Press on January 5, Senior Researcher Thom Scott-Phillips and Associate Professor Christophe Heintz  from Central European University (CEU)’s Department of Cognitive Science explain how and why humans, and only humans, evolved the cognitive capacities that, in turn, lead to massive diversity and open-endedness in how humans express themselves and communicate with one another. 

The researchers claim that this expressive diversity is united by an interrelated suite of cognitive capacities, the evolved functions of which are the expression and recognition of informative intentions. Language use is but one of these modes of expression, albeit one of manifestly high importance. They make cross-species comparisons, describe how the relevant cognitive capacities can evolve in a gradual manner, and survey how unleashed expression facilitates not only language use but novel behavior in many other domains too, focusing on the examples of joint action, teaching, punishment and art, all of which are ubiquitous in human societies but relatively rare in other species. 

The paper will be published in Behavioral & Brain Sciences in February, where it will be accompanied by commentaries from leading researchers in cognitive and evolutionary science, along with a reply from the authors. See a recent article about the research in New Scientist here.

Details and examples:

 Humans communicate and express themselves in many different ways – through language, pointing, nodding, winking, improvised behaviour (like hand gestures), subtle body movements (that connect dance partners) and the open-ended expressiveness of art. This richness and versatility is unique to humans. Bees, for example, communicate about the location of flowers and the quantity of their nectar, but apparently nothing else! What makes human communication so special? 

According to a new theory developed by CEU researchers Christophe Heintz and Thom Scott-Phillips, only humans have this type of communication because they are so socially cooperative. It doesn’t always seem so, of course. When your neighbour just keeps talking even when you’re trying to get away, or when one car driver is aggressive towards another, that doesn’t seem cooperative. But according to Heintz and Scott-Phillips, under the surface of all these communicative behaviours is still cooperation. 

When humans recognise that someone is trying to communicate with them, they unconsciously assume the other human is trying to help them. This is why, for instance, you still understand spoilers even if you’d prefer not to. You might know your friend is about the spoil the movie for you, and yet your mind automatically assumes they are being helpful, and so you understand the spolier even though you don’t want to. This is why we cannot ‘un-understand’ what others say. We don’t always believe what others mean, but we understand what they want us to believe. 

Going further, when a car driver aggressively tells another to get out of the way, this car driver is, in a way, being helpful with providing clear evidence of the intended meaning! People adjust their tone, words, body movements and anything else they might use to communicate, all to give the most useful evidence they can for what they mean. 

According to the CEU researchers, these cognitive capacities can only evolve in massively social species, where there are many opportunities for mutually beneficial interaction, and dangers of being tricked and misinformed. Author Thom Scott-Phillips says, “Humans find flexible and open communication so natural and ‘easy’ that we don’t always recognise how remarkable it is. But it’s very different to other species, and deep down it depends on a delicate balance of cooperation and vigilance”. 

The question for Heintz and Scott-Phillips was what makes us human. As evolutionary psychologists, they noticed how other great apes do sometimes behave with the intention to inform others, and how close this is to what humans do, but not yet the same—because the assumption of cooperativeness is missing. Strikingly, this assumption seems to be present in dogs, who unconsciously assume that when human owners attempt to get their attention, it is indeed worthwhile to pay attention. On the other hand, dogs do not have the same sort of deep social and Machiavellian intelligence that great apes have, which enable them to understand a wide variety of motives and ideas in communication. Humans combine dog-like assumptions of cooperativeness with great ape social skills.

Photo credit:

Elisabeth Warren (Primatologist, University of St. Andrews, Scotland)

Central European University (CEU) is accredited in the United States, Austria, and Hungary, and offers English-language bachelor's, master's and doctoral programs in the social sciences, the humanities, law, environmental sciences, management and public policy. With two campuses located in the heart of Central Europe – Vienna, Austria and Budapest, Hungary – CEU has a distinct academic and intellectual focus. The university combines the comparative study of the region's historical, cultural, and social diversity with a global perspective on areas of critical enquiry including good governance, sustainable development and social transformation.