Earlier this year, it was widely reported that chimpanzees could modify their calls to fit in with new groups. This research was centered around the relocation of a group of chimps from a Dutch zoo to one in Scotland, and claimed that over three years the continental apes learned a Scottish brogue. But now a different group of researchers has raised their doubts over this initial study, sparking a debate within the world of primatology.
The original piece of research followed incoming chimps from the Netherlands, and tracked changes in their calls as they integrated with a group of Scottish chimps, specifically looking at their grunt in reference to apples provided by keepers. They concluded that over time, the new chimps gave up their “Dutch” call for apples and instead started using the “Scottish” one. The implication, and what was then reported by the media, was that this shed light on the evolution of language, as the apes were able to pick up “accents” and new “words.”
But in a letter to Current Biology, another group of primatologists claims that these conclusions were overstated and that the calls from the Dutch chimps were actually not that different from the Scottish ones from the outset. They also report that the original study did not take into account the fact that the new chimps could simply have been “over aroused” when they first moved to Scotland, and that the change in their call could be in response to them settling in.
“Closer inspection of the data reveals that both groups largely overlapped in the range of calls they were originally giving in response to the apples,” Dr. Brandon Wheeler, one of the co-authors of the criticism of the original study, told BBC News. “There is a lot of variation in the data; there are clearly some individuals who are changing more than others.” In fact, he and his colleagues took the original data and worked it to show that there was only weak evidence for changes in vocalizations.
In light of these criticisms, the scientists who penned the first study have responded. They retort that if indeed the chimps were subject to high levels of arousal or excitement from being in a new and different environment, these differences would be seen in other behaviors aside from just their vocalizations. They also claim that the Scottish apes were exposed to other changes with the addition of 11 unknown chimps, but their vocalizations didn’t alter in this instance. Finally, they too took their original data again and reanalyzed it to show that it did indeed indicate a shift towards similar calls across the three years.
“We think that we've addressed the points that they bring up,” explained Dr. Simon Townsend, who co-authored the original study, to BBC News. “It's an interesting critique of our research – and this is exactly how science works.” In fact, if anything, this debate works well to highlight how two different groups can take the same set of data and yet draw two different conclusions, something which we could do well to bear in mind when looking at other scientific work.
[H/T: BBC News]