A “theory of mind” is essential for navigating social situations and interacting with others. While humans have a relatively developed theory of mind, its existence in other animals is debated. Two researchers at Johns Hopkins, Luke Townrow and Christopher Krupenye, investigated whether bonobos, our closest living relatives, can infer the mental state of humans they cooperate with.
To test this, the researchers used a simple setup involving three cups and a treat under one of them. A human experimenter would place the treat, and then the bonobo’s partner would identify the correct cup to receive the treat. In some experiments, the human had visibility into where the treat was hidden, while in others, they were blindfolded.
The results showed that the bonobos could tell when their human partner was ignorant about which cup contained the food. The bonobos consistently pointed to the correct cup more than eight times when their human partner was present, indicating a strong understanding of their mental state. This demonstrates that bonobos possess a limited theory of mind, allowing them to infer the mental state of humans they cooperate with.
Source: https://arstechnica.com/science/2025/02/bonobos-know-when-youre-clueless