A team of researchers created "demo" videos of an anonymous marmoset successfully activating a reward-giving apparatus (like a vending machine), then placed the apparatus in the Brazilian wilderness right in front of a screen playing the videos.
And wild marmosets loved it. The dashed up, watching the video intently, and those that saw a demonstrator marmoset (rather than a control video) were significantly better at operating the unfamiliar mechanism. This shows that marmosets can learn socially from a mere video playback of another marmoset. This connection is further confirmed by another result of the study: among marmots who were able to operate the contraption, they tended to use the strategy observed in the demo video (which varied among individuals; e.g., pulling a drawer versus opening a lid).
Social learning, particularly in the context of a video, requires patience, the ability to "put yourself in someone else's shoes," and an understanding that the video represents reality. Marmosets have all three traits, apparently; indeed, marmoset patience (compared to related primates) is well-known and has even been used as a basis for financial investment advice!
A further question worth exploring: would marmosets learn as well given a demonstration video without an actor? (E.g., with the mechanism operating without outside intervention)? A recent study on bearded dragons addressed this question, and found that the lizards learned better when the demonstration was performed by a conspecific.
This study is an amazing (and entertaining) addition to the literature on social learning, particularly for its methodological innovation! Hopefully in the future we will see even more studies conducted with video playback in the wild.
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.