Digging for Victory

Alba Motes Rodrigo is a PhD student in the ERC StoneCult project researching the origins of human culture and the problem solving abilities of great apes, currently working at the Department of Early Prehistory and Quaternary Ecology of the University of Tubingen (Germany). Previously, she completed a Bachelors in Biology at the University of Valencia (Spain) and a Masters in Applied Ethology and Animal Biology at the University of Linkoping (Sweden).

Alba spoke to Cultured Scene about her recent publication, “Chimpanzee extractive foraging with excavating tools: Experimental modeling of the origins of human technology”, published earlier this year in PloS One.

The paper

Cultured Scene: What is the key finding of your study?

Alba Motes Rodrigo: We found that captive task-naïve chimpanzees excavate the ground for artificially placed food using tools. The group we studied not only spontaneously performed this behavior but they employed a repertoire of excavating actions, most of them also performed by wild chimpanzees in different foraging contexts.

CS: Why is this topic important, and how do you feel it relates to social learning and cultural evolution more broadly?

AMR: This behavior had never been observed directly in the wild or in captivity. There were reports from two sites in the wild based on indirect evidence (excavated holes, abandoned tools, half eaten tubers, and so on) that this behavior existed, but researchers had never seen it directly. 

Our study allowed us to observe and characterize this behavior (and the tools involved) for the first time.

One of our aims was to determine if social learning was required for this behavior to emerge in naïve individuals. If this was the case, then the chimpanzees could not have figured out how to extract the food by themselves, but they did! This means that the excavating actions we observed do not necessarily depend on social learning to be acquired. As these actions also appear in the wild in other contexts (excavation of underground bee and termite nests), we suggest that their forms can also be individually acquired.

The process

CS: How did you arrive at the idea for the study?

AMR: This study was part of my master’s thesis at the University of Linköping (Sweden), which I did in collaboration with the University of Oslo (Norway). We based this study on some preliminary findings that another student, who is a coauthor on the paper, had reported, and expanded the scope of her initial aims. 

CS: What was the most challenging aspect of conducting the study?

AMR: I think that the most difficult part was probably the writing-up phase. The study included both data I had collected and data collected by someone else. This made coding and analysing the data very complicated. However, the experience taught me very useful skills such as to be very organized with my coding sheets, label properly all the files, and to keep a clear log of  the data collection.

CS: What were the best and worst aspects of data collection – any funny stories?

AMR: Honestly, data collection was great. I got to spend 4 months in a lovely Norwegian village by the beach studying chimpanzees. Probably the hardest periods were when it rained for weeks at a time. I was doing my experiment in an outdoor island and it was not fun to excavate holes in the mud, specially if the chimpanzees then couldn’t be bothered to go outside because it was wet.

Getting stuck in – if you want to know if chimpanzees will dig, you first have to bury something for them to dig for….


CS: How did you manage the writing process? Was it straight forward, or were there  challenges?

AMR: The writing process was really really hard. It took two years and countless versions to publish the paper. We redid our analysis along the way because I learned more statistics after my masters and realized I could do better, so I had to start over. As I mentioned before, I also had  difficulties analysing the data I had not collected myself, which really slowed down the  process. However, at the end I learned a lot from the project and I am very happy it is finally  published.

CS: How was the peer review process? 

AMR: The process was great and really educational, it was just very long. Before the final submission, the manuscript was rejected twice. It was hard to maintain the level of motivation necessary to continue working on the manuscript after the second rejection, but I really thought our data deserved to be published. After very supportive conversations with friends and family, they convinced me that we had been given the chance to write an even better paper. And I think we did. 

I believe I was also very lucky in the sense that we had some really engaged reviewers who made incredibly good reviews. That also helped a lot to bring the paper to its final stage.

What’s next?

CS: Will you be following up on this research? What questions interest you next, based on  your findings? 

AMR: I would love to, but unfortunately it will have to wait until I finish my PhD. At the moment I  have my hands full with other things, so I am putting the project on hold. In the future I would really like to be able to study the behavior in the wild in those populations where it has  been found, and compare it with our findings from captivity. 

CS: As early career researchers, we’re always learning. Is there anything you’d do differently in future, based on your experiences conducting this study?

AMR: I will definitely think about it twice before agreeing to analyse jointly data collected by different researchers. New projects such as ManyPrimates (https://manyprimates.github.io) are a great way to avoid problems similar to the ones I had. 

CS: Finally – what do you think are some of the big questions / challenges facing the field of cultural evolution and social learning?

AMR: I think we need more comparative data from different species collected using equivalent methodologies. Projects such as PanAf and ManyPrimates will really help in this regard and will give researchers access to a vast amount of data. More and more labs are now using  common methodologies to study different aspects of behavior such as gestural communication, which I also find really cool. I think there is still a lot we don’t know about  how behaviors first appear in populations, which is a very challenging topic because they are  very restricted in time and you need huge records of past behavior.