Traditionally regarded as a uniquely human trait, the ability to discern when a companion could benefit from a hint has emerged as a cognitive aptitude shared with our primate relatives.

Researchers at Johns Hopkins University in Maryland conducted an illuminating study focusing on bonobos (Pan paniscus), which provided insights into the ways these apes guided human researchers towards concealed treats—an endeavor they were eager to consume.

Such findings unveil cognitive parallels among hominins that were previously unrecognized, potentially extending back millions of years to our shared ancestral lineage.

According to psychologist Chris Krupenye, “The capacity to detect gaps in others’ knowledge lies at the core of our most advanced social interactions, fundamentally shaping our collaborative, communicative, and strategic engagements.”

In the experimental framework, three male bonobos engaged in a turn-taking game with a researcher, wherein treats were strategically concealed beneath cups—occasionally under the researcher’s scrutiny and at other times without. Successful identification of the treat enabled the ape to partake in it.

The results illustrated that bonobos were notably more inclined to gesture and point towards the cup concealing the treat when the researcher exhibited ignorance regarding its location.

Though this might appear as a rudimentary behavior, it signifies a profound understanding of how our closest evolutionary relatives can cognitively evaluate the perspectives of others. Prior studies have documented instances of apes alerting their companions to possible dangers; however, these recent experiments disentangle such instincts from group dynamics, thereby exploring individual cognitive capacities.

As psychologist Luke Townrow aptly notes, “What we’ve demonstrated is that apes will communicate with a partner to modify their behavior, yet a pivotal question for future exploration is whether they seek to alter their partner’s mental state or beliefs.”

This theory of mind—the understanding that others possess distinct beliefs or perspectives—has historically been perceived as a distinguishing feature of human cognition.

Emerging evidence now suggests that this cognitive flexibility may also inhabit ape populations, as bonobos are observed to simultaneously grasp two conceptual frameworks: the location of the treat and their partner’s knowledge of it. Such groundbreaking insights warrant further investigation in subsequent research endeavors.

A compelling inquiry for future study could pertain to the motivations underlying these bonobo behaviors: do they aspire to shift their partner’s mental frameworks, or merely modify their conduct? Anticipation brews for more experiments centering around concealed treats.

“Ongoing debates within the field regarding primate capabilities find validation in our research, confirming that these remarkable cognitive capacities exist, contrary to scepticism from certain quarters,” asserts Krupenye.

The findings of this research have been published in PNAS.