If you want to have a rich social life, you're going to need to know who's who. You'll need to distinguish friend from foe, sister from stranger. And you're going to need to hold those distinctions in your head— for at least a little while. This is true not just for humans but—we have to assume—for other social species as well. But which species? And for how long can other creatures hold on to these kinds of social memories?

My guests today are Dr. Laura Lewis and Dr. Chris Krupenye. Laura is a biological anthropologist and postdoctoral scholar at UC Berkeley; Chris is a comparative psychologist and an Assistant Professor at Johns Hopkins. Along with a larger team, Laura and Chris recently authored a paper on memory for familiar faces in chimpanzees and bonobos. In it, they show that our closest cousins remember their groupmates for decades.

Here, we chat about the paper and the backstory behind it. We consider the anecdotes about long-term memory in great apes—and how Laura and Chris decided to go beyond those anecdotes. We talk about the evidence for complex social memory across the animal kingdom. We discuss the use of eye-tracking with primates and its advantages over earlier methods. We also talk about why long-term social memory might have evolved. Along the way, we touch on dolphins, ravens, and lemurs; voices, gaits, and names; the different gradations of recognition; and how memory serves as a critical foundation for social life more generally.

Alright friends, without further ado, here's my conversation with Laura Lewis and Chris Krupenye. Enjoy!

A transcript of this episode is available here.

Notes and links

4:30 – Dr. Lewis and Dr. Krupenye worked together in the lab of Dr. Brian Hare, a former guest on the podcast.

8:30 – The video of Mama and the primatologist Jan van Hooff.

12:00 – For research on the remarkably long social memories of dolphins, see here.

14:00 – For research on long-term voice recognition in bonobos, see here.

19:30 – Another collaborator on the paper we're discussing was Dr. Fumihiro Kano, affiliated with the Kumamoto Sanctuary.

29:30 – For more on the use of eye-tracking with primates, see a recent review paper by Dr. Lewis and Dr. Krupenye.

34:00 – For the previous study by Dr. Lewis, Dr. Krupenye, and colleagues about how bonobos and chimpanzees attend to current groupmates, see here.

41:00 – A popular article reviewing bonobo social behavior.

54:30 – A research paper on individual recognition by scent in chimpanzees.

55:30 – A research paper on individual recognition by butt in chimpanzees.

Recommendations

'Long-term memory for affiliates in ravens'

'Decades-long social memory in bottlenose dolphins'

'Enduring voice recognition in bonobos'

Many Minds is a project of the Diverse Intelligences Summer Institute, which is made possible by a generous grant from the Templeton World Charity Foundation to UCLA. It is hosted and produced by Kensy Cooperrider, with help from Assistant Producer Urte Laukaityte and with creative support from DISI Directors Erica Cartmill and Jacob Foster. Our artwork is by Ben Oldroyd. Our transcripts are created by Sarah Dopierala.

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