In a discovery that illuminates the deep roots of human cognitive development, researchers have found that great apes process visual information about social interactions in ways strikingly similar to adult humans. This finding suggests that some of the mental machinery underlying human language existed long before we began to speak.
Published in PLOS Biology | Estimated reading time: 4 minutes
Tracking the Roots of Understanding
Lead researcher Dr. Vanessa Wilson from the University of Neuchatel, Switzerland, alongside an international team of scientists, has uncovered remarkable similarities in how apes and humans visually process events. Their study, conducted at the Basel Zoo, compared the eye movements of humans and great apes as they watched short video clips of various interactions.
The research team, which included collaborators from both Switzerland and the United Kingdom, examined the viewing patterns of 14 human adults, five chimpanzees, two gorillas, and two orangutans. They also studied 29 six-month-old human infants, leading to some unexpected findings about early human development.
A Shared Mental Framework
The study revealed that both apes and adult humans primarily track what scientists call “agent-patient relationships” – the interaction between the doer of an action and the receiver of that action. Like humans watching a cat chase a mouse, the apes alternated their attention between the key players in each scene, demonstrating a sophisticated understanding of social interactions.
However, the similarities weren’t perfect. While human adults focused almost exclusively on the main actors in each scene, apes devoted more attention to background details. Both groups showed increased interest in the active participant (the agent) when food appeared in the videos, suggesting shared priorities in certain contexts.
Implications for Language Evolution
“Our findings are consistent with a shared cognitive mechanism between humans and apes, suggesting that event role tracking evolved long before language,” explains Dr. Wilson. This conclusion gained additional support from an unexpected source: the behavior of human infants, who, unlike both adult humans and apes, focused primarily on background elements rather than the main actors.
The research team showed participants 84 short video clips, carefully tracking their eye movements to understand how they processed the information. When examining the results, they found that apes, like human adults, could decompose causal actions into agent and patient roles – a cognitive skill previously thought to be uniquely human.
These findings open new avenues for understanding how human language evolved. While apes possess the basic cognitive architecture for tracking social interactions, they don’t develop complex language like humans do. Future research will need to explore this gap, investigating what additional cognitive elements emerged in human evolution to enable the development of complex language systems.
Key Terms
- Agent-Patient Relationship
- The connection between the performer of an action (agent) and the receiver of that action (patient) in an event.
- Event Role Tracking
- The cognitive ability to follow and understand the roles different participants play in an interaction or event.
- Visual Fixation
- The point where a subject’s eyes focus when observing a scene, measured through eye-tracking technology.
How did human infants’ viewing patterns differ from adults and apes?
Six-month-old infants paid more attention to background elements instead of focusing on the main actors in the scenes.
What happened when food appeared in the video clips?
Both apes and humans showed increased attention to the agents (performers of actions) when food was involved in the scenes.
What key difference was observed between apes and human adults?
While both groups tracked the main actors, apes showed more attention to background details compared to humans, who focused almost exclusively on the agents and patients.
Why is this research significant for understanding language evolution?
It suggests that event role tracking, a cognitive foundation for language, evolved before human speech, as it’s present in both humans and great apes.
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