Marmosets Find Videos Educational, if Not Viral

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Wild monkeys can learn from a demonstration video set up in the forest.

Wild marmosets in the Brazilian forest can learn quite successfully from video demonstrations featuring other marmosets, Austrian scientists have reported, showing not only that marmosets are even better learners than previously known, but that video can be used successfully in experiments in the wild.

Tina Gunhold, a cognitive biologist at the University of Vienna, had worked with a population of marmoset monkeys in a bit of Brazilian forest before this particular experiment.

The forest is not wilderness. It lies near some apartment complexes, and the marmosets are somewhat used to human beings. But the monkeys are wild, and each extended family group has its own foraging territory.

Dr. Gunhold and her colleagues reported in the journal Biology Letters this month that they had tested 12 family groups, setting up a series of video monitors, each with a kind of complicated box that they called an “artificial fruit.”

All the boxes contained food. Six of the monitors showed just an unchanging image of a marmoset near a similar box. Three of them showed a marmoset opening the box by pulling a drawer, and three others a marmoset lifting a lid to get at the food.

Marmosets are very territorial and would not tolerate a strange individual on their turf, but the image of a strange marmoset on video didn’t seem to bother them.

Individual marmosets “differed in their reactions to the video,” Dr. Gunhold said. “Some were more shy, some more bold. The younger ones were more attracted to the video, perhaps because of greater curiosity.”

But, she said, the ones that watched the demonstrations were much better at getting the box open than the ones that had the placebo monitor, and they also tended to use the specific skill demonstrated, pulling the drawer open or lifting the lid.

The reason for studying how potent this kind of social learning is in different animals, Dr. Gunhold said, is that it provides clues to how human learning and the passing on of traditions may have first evolved.

Chimpanzees and dolphins have been shown to pass on certain traditions, such as how to feed or hunt. There’s no evidence of that yet in marmosets, Dr. Gunhold said, but this kind of imitation of strangers “is a high level of social learning.”

Perhaps online courses are next.