The movie The Social Network has been in the news this week — as it’s been for the last six months or so — for racking up eight Academy Award nominations. It’s a great film, and, as we’ve seen, great fodder for an ongoing conversation on peer networking and the entire nature of the world we live in today (as well as for debate on whether or not it was fair in its depiction of its subject: Facebook founder Mark Zuckerberg). But one moment in the film is particularly significant for learning professionals.

In a short scene, a reportedly true story, Zuckerberg hasn’t been attending a class on art history. To make up for this, he creates a website with all the paintings in the class syllabus on it, with comment fields underneath each painting. He then sends this to all his classmates, billing it as a study aid. The other students fill in information on and interpretations of the paintings as discussion. Zuckerberg uses this to quickly learn everything he needs to know to pass the class – and this also has the effect of improving the grades of the class overall.

This story relates to what learning professionals have been experiencing in the last decade or so in terms of learning delivery – considering whether to stick to formal learning or venture into informal learning via peer networking and other methods. Within the learning and development profession, there’s been a repeatedly expressed sentiment that all you need to do to facilitate learning is provide workforces with the information; they’ll find what they need themselves and learn, as Zuckerberg did when he didn’t attend class.

But such informal learning’s lack of structure has a certain risk to it; in that students not called on to prove they learned anything may actually learn little or nothing. Formal learning means testing what the student learned. As any educator likely knows, tests provide more than a way to grade students on what they learned; they’re a means to an end – a vehicle by which students learn. Recent research bears this out.

According to a study published last week in the journal Science, test-taking cements knowledge better than studying. A New York Times article on this reported that in this research “students who read a passage, then took a test asking them to recall what they had read, retained about 50 percent more of the information a week later than students who used two other methods.”

In approaching informal learning, learning and development professionals should keep this in mind. Giving employees the information they need to succeed is great. But neglecting to test them on it is a gamble. After all, Zuckerberg used peer networking to quickly learn what he needed to know, but only did it to ace a test. Without that hurdle in front of him, he probably would have just kept his nose stuck in a mass of computer code.