Lots of animals communicate with each other, from tiny mice to enormous whales. But none of those forms of communication share even a small fraction of the richness of human language. Still, finding new examples of complex communications can tell us things about the evolution of language and what cognitive capabilities are needed for it.
On Monday, researchers reported what may be the first instance of a human-like language ability in another species. They have evidence that suggests that elephants refer to each other by individual names, and the elephant being referred to recognizes when it's being mentioned. The work could benefit from replication with a larger population and number of calls, but the finding is consistent with what we know about the sophisticated social interactions of these creatures.
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he researcher worked with recordings of elephant calls made in three distinct social contexts. One was a contact call, made when a group member is far enough away that they are no longer visible and was used to re-establish contact. A second is greeting calls, which are made when an individual approaches another. And the third was a caregiving call given to young offspring within the group. Calls were used for analysis if the researchers could clearly identify a recipient of the call.
The rumbles elephants produce are harmonically complex, and it's difficult to identify important features by looking over things like frequency plots. So, the researchers used two methods of examining them. One was a machine-learning approach called a random forest model that can be used for classification tasks. Separately, they used audio analysis software to identify the degree to which any two calls share common features.
Once the system was set up, it correctly identified the recipient in over a quarter of the calls analyzed, much higher than would be expected based on random chance. That may seem low, but recall that it may not always be necessary to call out an individual's name each time you communicate with them.
The researchers also analyzed calls from one individual directed toward another. They had higher levels of similarity to each other than they did to any calls to different individuals. This was true regardless of social relationships among the individuals or the context in which the call was being made. Social context also mattered as it was easier to detect names in contact and caregiving contexts.