Until chimpanzees were discovered to crack nuts, dip for termites, and use leaves as sponges, it was long thought that the use of tools was a defining human characteristic. We now know that to be wrong, but questions still remain as to how both humans and apes learn the capacity to use tools. It has generally been assumed that while basic tool use in human children has to be socially learned, young chimpanzees will spontaneously invent tool behavior themselves, rather than having to be first shown by an adult.
A new study, however, has found that human children don’t actually require this social learning for all tool use, but can create tools to solve novel problems in a completely unsolicited way in a capacity similar to young chimpanzees. The researchers of the paper, published in the Proceedings of the Royal Society B, set human children various tasks based on problem solving that chimps do in the wild, and found that in all but one of the cases the children spontaneously developed the correct tool to solve them.
It has been argued that the complexity and variety of human tool use is in part down to the fact that “humans use imitation and teaching to accumulate innovations over time,” write the study’s authors. Chimpanzees, on the other hand, “acquire tool-use behaviours mostly by individual re-inventions.” Young apes may watch adults complete a task, but they then figure it out by themselves through trial and error. The researchers wanted to see if human children were also capable of this “spontaneous” tool development.
The team took 12 tool-based behaviors that have been observed in wild chimpanzees, half of which were frequently observed, such as dipping for ants with a stick, while the other half were less common, for example using a piece of rock to crack nuts open. They then devised a series of tasks that mimic the same tool use to test 50 children aged between two and a half and three years old, the age at which young chimps have been observed to master simple tool use. For example, where chimpanzees will use a twig to extract seeds from a nut or fruit, the children were tasked with using a twig to remove a pom pom from a box. The researchers report that the children managed to accomplish 11 out of the 12 tasks successfully.
“The idea was to provide children with the raw material necessary to solve the task,” explains Dr. Claudia Tennie, who coauthored the study. “We told children the goal of the task, for example to get the pom poms out of the box, but we never mentioned using the tool to them. We would then investigate whether children spontaneously came up with the correct tool behaviour on their own.”
The researchers conclude that while more complex tool use in humans may require social learning, the idea that all tool use does, is apparently wrong. If human children and chimpanzees both have this basic ability to create tools, it also suggests that the last common human-chimpanzee ancestor might have been able to do the same.
2