Persistent Social Memories in Apes: A Landmark Study

by Liam O'Connor
Ape Social Memory

Recent research has revealed that apes have an extraordinary ability to remember past social connections, recognizing old group members even after a hiatus of over 25 years. This discovery highlights a significant cognitive parallel between apes and humans, emphasizing the enduring nature of social bonds among our closest animal kin.

The study records the most enduring social memories observed in a non-human species to date.

Apes demonstrated recognition of former groupmates through photographs, exhibiting heightened response to images of those they were previously close with, according to recent research findings.

This investigation, revealing the most prolonged social memory recorded in any species apart from humans, emphasizes the evolutionary links between human cultural development and our shared ancestry with apes. The research was recently published in the Proceedings of the National Academy of Sciences.

Christopher Krupenye, the study’s lead researcher from Johns Hopkins University and an expert in animal cognition, commented, “Chimpanzees and bonobos can identify individuals they have not seen in decades. There’s a noticeable pattern where they pay more attention to individuals with whom they had stronger relationships. This suggests they’re not just recognizing faces; they’re remembering the nature of their past relationships.”

The study has been credited to Johns Hopkins University.

Laura Lewis, a co-author and a biological anthropologist at the University of California, Berkeley, added, “Our findings challenge the perception of great apes as markedly different from humans by showing they possess cognitive abilities very similar to ours, including memory.”

Research Methodology

The study originated from the researchers’ personal experiences with apes, noting their apparent recognition of the researchers even after long absences.

“We felt that they recognized us, differentiating us from typical zoo visitors,” Krupenye explained. “This led us to empirically investigate whether they truly retain long-term memories of familiar social partners.”

The research involved chimpanzees and bonobos from zoos in Scotland, Belgium, and Japan. The team gathered photos of apes that had either left the zoos or passed away, some not seen by the study subjects for up to 26 years. They also gathered data on the nature of each ape’s past interactions with these former groupmates.

The apes were invited to participate in the study by being offered juice. While drinking, they were shown two photographs side-by-side: one of an ape they once knew and one of a stranger. The researchers then used non-invasive eye-tracking technology to measure the apes’ gaze duration, hypothesizing that they would look longer at familiar individuals.

Findings and Implications

The apes consistently looked longer at pictures of former groupmates and even more so at those they had positive interactions with in the past.

In a notable instance, bonobo Louise had not seen her sister Loretta and nephew Erin for over 26 years. Yet, she displayed a significant preference for their images in multiple trials.

The study suggests that the social memory of great apes could surpass 26 years, a significant portion of their 40 to 60-year lifespan, potentially mirroring the human capacity for long-term memory retention.

The researchers also posited that this kind of memory might have existed millions of years ago in our common ancestors, laying the groundwork for the evolution of human culture and complex social interactions such as long-term intergroup relations.

Additional Insights and Future Research Directions

The study also opens up questions about whether apes miss their former companions, especially friends and family.

“Our research doesn’t confirm if they miss others, but it does suggest they have the cognitive ability to do so, a trait once thought to be uniquely human,” Lewis stated.

The researchers aim to deepen our understanding of great apes, many of which are endangered, and explore how separation due to threats like poaching and deforestation might impact them.

“Our findings emphasize the importance and lasting nature of these social bonds. Disruptions to these relationships could be profoundly detrimental,” Krupenye remarked.

Future research may explore whether such long-term social memories are unique to great apes or common among other primates. The researchers are also interested in investigating the depth and richness of apes’ memories, including their ability to remember experiences as well as individuals.

The study, titled “Bonobos and chimpanzees remember familiar conspecifics for decades,” was published on 18 December 2023 in the Proceedings of the National Academy of Sciences.

The research was funded by a Templeton World Charity Foundation grant and the CIFAR Azrieli Global Scholars program.

Team members included Erin G. Wessling from Harvard University and the University of Göttingen; Fumihiro Kano from the Max Planck Institute of Animal Behavior; Jeroen M. G. Stevens from Odisee University in Belgium, and Josep Call from the University of St Andrews.

Frequently Asked Questions (FAQs) about Ape Social Memory

Do apes have long-term social memory?

Yes, a recent study has shown that apes can recognize former groupmates even after more than 25 years, indicating they possess long-term social memory.

How does ape social memory compare to human memory?

Ape social memory is remarkably similar to human memory in its duration and depth. Apes can remember individuals and the nature of their relationships for a significant portion of their lifespan, comparable to humans.

What does the ape social memory study reveal about human evolution?

The study suggests that the long-lasting social memory in apes and humans likely originated millions of years ago in our common evolutionary ancestors, contributing to the development of human culture and complex social interactions.

Are the findings of the ape memory study relevant to conservation efforts?

Yes, the findings highlight the importance of social bonds in apes, underscoring the potential impact of threats like poaching and deforestation, which disrupt these relationships. This knowledge is vital for conservation strategies.

What future research directions are suggested by this ape memory study?

Future research may investigate whether such extended social memories are exclusive to great apes or seen in other primates. Researchers are also interested in exploring the richness of ape memories, such as their ability to remember experiences as well as individuals.

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Mark Johnson December 22, 2023 - 7:04 pm

interesting study, but i wonder how they measure the ape’s memory accuratly? It seems like a difficult thing to do.

Emma Brown December 22, 2023 - 7:52 pm

i read about this on another site, it’s really fascinating! It’s sad though to think about the impact of deforestation on these intelligent creatures.

Sarah Wilson December 23, 2023 - 2:43 am

Great article! it’s a reminder of how complex animal behavior is, we often underestimate them.

David Lee December 23, 2023 - 5:35 am

This is cool and all but what about other animals? do they have similar abilities or is it just apes?

Jane Smith December 23, 2023 - 9:55 am

Wow, this is amazing! Apes can remeber their friends for over 25 years, just shows how similar they are to us humans.


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