First they exposed them to new foods and plastic snakes and other novelties.
The ones who had spent their youth in the forest, learned the lessons of caution well. They didn’t try new foods, avoided the fake snake and in general showed the expected lack of curiosity.
Which makes sense. “Imagine you were dropped in the middle of a rain forest,” said Dr. Damerius. It would be unwise to touch all the plants, let alone pop them in your mouth.
But the orangutans raised by humans or brought to a rehab center at a young age experienced a relatively safe environment and human role models who were themselves curious. They were far more likely to eat the dyed purple rice or potato mush, and to investigate a fake snake.
In the second part of the experiment, the researchers used a variety of cognitive tests, requiring the apes to figure out how to open a box, or reach into a chamber in an awkward way to get a treat, or other tasks.
The more curious orangutans did much better.
Dr. Damerius said the research showed several things. It confirmed what is called the captivity effect, that time spent in a zoo or other safe environment promotes curiosity.
And it also showed that the younger the apes were when they spent time with humans the more curious they were. Orangutans that grew up in the forest did not have a big spike in curiosity from being at a rehabilitation center.
It also showed that curiosity helps in what are usually thought of as intelligence tests. “Curiosity is contributing to problem solving,” Dr. Damerius said. ”It increases the opportunities for learning.”
In addition, a species thought to be incurious turned out to be quite curious in the right circumstances. So this was a matter of environmental influence, not genetic endowment. She said it was “striking” that the different environment could elicit curiosity in orangutans. “I think there is this dormant, inherited potential.”
The findings do raise a question, she said, about what it means to release an orangutan with more developed curiosity back into the wild, where it may well be the unexamined snake that makes life possible, let alone worth living.