Frans de Waal (1948-2024)

 The eminent primatologist Frans de Waal has passed away. Here's a memoriam from Emory University:

Emory primatologist Frans de Waal remembered for bringing apes ‘a little closer to humans’

I sometimes show the video below about his experiment with monkeys on fairness (and being treated unfairly) to my class on experimental economics (typically when I'm about to talk about the ultimatum game).

"Two capuchins were situated in enclosures next to one another. A researcher would ask them to do a task and if they succeeded give them a treat. The catch was one monkey was always rewarded with a piece of cucumber while the other monkey sometimes got a piece of cucumber and sometimes got a grape — a preferred treat among capuchin monkeys.

"A video de Waal filmed of one of the experiments created a media sensation.

Unequal pay for equal work: When the first monkey gives the researcher a rock, she is rewarded with a cucumber slice. But watch what happens when the first monkey sees the second monkey hand the researcher a rock — and get a much tastier grape instead.

"A monkey that received only cucumber appears perfectly happy until she sees her companion receive a grape. Then her behavior changes. She accepts the next piece of cucumber only to throw it back at the researcher, pounding the surface in front of the enclosure and shaking its Plexiglas walls.

“That video struck home with a lot of people,” Brosnan says. “Who hasn’t felt like that monkey that’s only getting cucumbers? Our research showed something about the evolution of the sense of human fairness.”