Child development specialists often evaluate a patient’s ability to complete tasks involving multiple steps. It turns out, many chimpanzees would pass these tests with flying colors, according to a report in the journal PeerJ.
“We find objective evidence that wild chimpanzees break down technical tasks into manageable subtasks, and address these subtasks one-by-one, similarly to humans,” says Elliot Howard-Spink, an author of the study. He performed the research while at Oxford, but now is at the Max Planck Institute of Animal Behavior.
How Chimps Breakdown Tasks
Both humans and chimps rely on two separate, but related strategies. First, they sequence — dividing complex tasks into discrete steps. Then they chunk by bundling related steps together.
One way to compare these behaviors is by looking at how both chimps and humans process foods. While human cooking may outwardly appear more complex, with both more items in the sequence and within each chunk, the approach is generally the same.
“Nut cracking is one of the most complex naturally occurring tool-use behaviors seen in any nonhuman animal, as it involves coordinating several objects at the same time (nut, hammer stone, and anvil stone)," says Howard-Spink. “Chimps need to collect together their tools and nuts, correctly organize them, and once nuts are cracked, they often perform several peeling actions.
“Now compare that with human food processing behaviors, and all the steps required to make even a simple meal,” says Howard-Spink. “We have way more objects, more steps, and rather than the process taking minutes, it can even take hours.”
Read More: Chimps May Continuously Learn as They Age, a Factor of Human Evolution
Removing Human Bias
Previous studies have observed these behaviors in chimps. But the new research uses mathematical analysis rather than relying solely on human judgement. For instance, looking for chunking can be highly subjective. What makes a chunk? Is it one or two chunks, when a chimp pauses to reorganize objects, but returns to the same task? How many chunks exist when a chimp stops peeling, strikes the nut with a tool, then returns to peeling?
“Humans are heavily biased to see chunks, even when there are none, meaning that we couldn’t necessarily say that these chunks exist," says Howard-Spink.
To remove human bias, the scientists leaned heavily on statistics. That way, they could dispassionately probe thousands of action combinations of different lengths. These abstract statistical relationships could help answer the question: chunk or not a chunk.
Read More: Can Animals Learn Language Like Humans Do?
Learning Patterns
However, direct observations revealed some interesting patterns of chimp learning and development. The two youngest chimps the researchers observed showed some signs of chunking. But they also saw that, just like human children, they can get easily distracted.
“When using stone tools, adults crack nuts efficiently, whereas younger individuals tend to be less efficient, and especially when very young, frequently play with nuts and stones,” says Howard-Spink.
The group intends to further study how chunking of tool-action sequences emerges during the development of wild chimpanzees. They also would like to learn when these behaviors emerged through evolution.
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Before joining Discover Magazine, Paul Smaglik spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.
