The kids are smarter than you think
Young chimpanzees are remarkably innovative, inventing tools and improving on ones that adults use - and this technical know-how could hold the key to better appreciating the role of children in the evolution of all cultures, including ours.
That's what scientists led by an anthropologist at Université de Montréal conclude in a new study.
Published in the Nature journal Scientific Reports, the paper explores the tool-making skills of three dozen immature chimps at the Ngogo research site in Kibale National Park, a heavily forested area in southwestern Uganda where a large population of chimps live in the wild.
"This paper is about evolution of culture in humans, using chimps as a model of comparison, and the take-home message is that children could be more important figures in cultural evolution than previously thought," said Bădescu, an associate professor of anthropology at UdeM.
"At their stage of development kids are allowed to be creative and to explore. They can experiment with tools and objects and this leads to new and innovative ways of using them. It introduces variation into the repertoire of skills that adults can pick up on, and that's how culture evolves."
In Uganda, where she spent much her time studying chimps, Bădescu has observed that kids intelligently used moss as a sponge tool to soak up and drink water, for instance.
"We don't often think of kids as being the innovators of technology, but they can indeed be important," Bădescu said. "For anyone interested in how culture is created, regardless of their academic disciplines, these observations and results should be quite interesting."
Origins of innovation explored
In her study, done with scientists at Arrhus University in Denmark as well as the University of Toronto and Yale University, Bădescu notes that innovation drives cultural evolution yet little is known about its developmental origins or the role of immature individuals generating novel behaviors.
Over 15 months in 2013-2014 and 2018, Bădescu examined 67 different uses of objects by 36 infant and juvenile chimpanzees (Pan troglodytes schweinfurthii) at the Ngogo field site. Nearly half of those uses were atypical, deviating from adult norms, she found.
Of those, almost all - 94 per cent - were new uses or modifications of adult forms or uses in new contexts, including three innovations: playing with a "doll" (a tree stump carried as if it were an infant), sponging up water with a tuft of moss, and clipping leaves to signal wanting to be carried.
Others used stick tools to probe for and eat honey from honeycombs, as well as to fish for and eat termites. They also used tools in social contexts, for instance 'leaf grooming' of each other, much like the adults do, but in their own way.
An 'exploration index'
To assess individual differences, Bădescu and her team developed an "exploration index" integrating frequency, diversity and atypicality of object use. Nine individual chimpanzee children had notably higher scores.
Females and offspring of mothers of several children scored higher, indicating the positive effects of sex and social support from experienced mothers and siblings.
"These findings suggest that immatures generate novelty at the margins of species-typical behaviour yet vary in their propensity to innovate," the co-authors conclude in their study.
"A permissive social environment for object play may be key to the developmental pathways of innovation, providing a generative context for behavioural variation on which social learning and selection can act," they write.
"If retained and transmitted, even rare innovations by immatures could contribute to the accumulation of cultural complexity."
Journal
Scientific Reports
Method of Research
Observational study
Subject of Research
Animals
Article Title
Atypical tool and object use in wild immature chimpanzees reveals developmental pathways to innovation
Article Publication Date
27-Oct-2025
New psychology study suggests chimpanzees might be rational thinkers
A new study published in Science provides evidence that chimpanzees can rationally revise their beliefs when presented with new information
University of California - Berkeley
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“This research can help us think differently about how we approach early education or how we model reasoning in AI systems,” said Emily Sanford, a researcher at UC Berkeley. “We shouldn’t assume children are blank slates when they walk into a classroom.”
view moreCredit: Sabana Gonzalez / Social Origins Lab
Chimpanzees may have more in common with human thinkers than previously thought. A new study published in Science by researchers provides evidence that chimpanzees can rationally revise their beliefs when presented with new information.
The study, titled “Chimpanzees rationally revise their beliefs,” was conducted by a large research team that included UC Berkeley Psychology Postdoctoral Researcher Emily Sanford, UC Berkeley Psychology Professor Jan Engelmann and Utrecht University Psychology Professor Hanna Schleihauf. Their findings showed that chimpanzees — like humans — can change their minds based on the strength of available evidence, a key feature of rational thought.
Working at the Ngamba Island Chimpanzee Sanctuary in Uganda, the researchers presented chimps with two boxes, one containing food. Initially, the animals received a clue suggesting which box held the reward. Later, they were given stronger evidence pointing to the other box. The chimps frequently switched their choices in response to the new clues.
“Chimpanzees were able to revise their beliefs when better evidence became available,” said Sanford, who is a researcher in the UC Berkeley Social Origins Lab. “This kind of flexible reasoning is something we often associate with 4-year-old children. It was exciting to show that chimps can do this too.”
To ensure the findings reflected genuine reasoning rather than instinct, the team incorporated tightly controlled experiments and computational modeling. These analyses ruled out simpler explanations, such as the chimps favoring the latest signal (recency bias) or reacting to the most obvious cue. The models confirmed that the chimps’ decision-making aligned with rational strategies of belief revision.
“We recorded their first choice, then their second, and compared whether they revised their beliefs,” Sanford said. “We also used computational models to test how their choices matched up with various reasoning strategies.”
The study challenges the traditional view that rationality — the ability to form and revise beliefs based on evidence — is exclusive to humans.
“The difference between humans and chimpanzees isn’t a categorical leap. It’s more like a continuum,” Sanford said.
Sanford also sees broader applications for this research. Understanding how primates revise beliefs could reshape how scientists think about learning, child development and even artificial intelligence.
“This research can help us think differently about how we approach early education or how we model reasoning in AI systems,” she said. “We shouldn’t assume children are blank slates when they walk into a classroom.”
The next phase of her study brings the same tasks to children. Sanford’s team is currently collecting data from two- to four-year-olds to compare how toddlers and chimps revise beliefs.
“It’s fascinating to design a task for chimps, and then try to adapt it for a toddler,” she said.
Eventually, she hopes to extend the study to other primate species as well, building a comparative map of reasoning abilities across evolutionary branches. While Sanford has worked on everything from dog empathy to numerical cognition in children, one lesson remains constant: animals are capable of much more than we assume.
“They may not know what science is, but they’re navigating complex environments with intelligent and adaptive strategies,” she said. “And that’s something worth paying attention to.”
Other members of the research team include: Bill Thompson (UC Berkeley Psychology); Snow Zhang (UC Berkeley Philosophy); Joshua Rukundo (Ngamba Island Chimpanzee Sanctuary/Chimpanzee Trust, Uganda); Josep Call (School of Psychology and Neuroscience, University of St Andrews); and Esther Herrmann (School of Psychology, University of Portsmouth).
Journal
Science
Subject of Research
Animals
Article Title
Chimpanzees rationally revise their beliefs
Article Publication Date
30-Oct-2025
