Facebook upgrades its AI to better tackle COVID-19 misinformation and hate speech


Facebook’s AI tools are the only thing standing between its users and the growing onslaught of hate and misinformation the platform is experiencing. The company’s researchers have cooked up a few new capabilities for the systems that keep the adversary at bay, identifying COVID-19-related misinformation and hateful speech disguised as memes.


Detecting and removing misinformation relating to the virus is obviously a priority right now, as Facebook and other social media become breeding grounds not just for ordinary speculation and discussion, but malicious interference by organized campaigns aiming to sow discord and spread pseudoscience.


“We have seen a huge change in behavior across the site because of COVID-19, a huge increase in misinformation that we consider dangerous,” said Facebook CTO Mike Schroepfer in a call with press earlier today.


The company contracts with dozens of fact-checking organizations around the world, but — leaving aside the question of how effective the collaborations really are — misinformation has a way of quickly mutating, making taking down even a single image or link a complex affair.


Take a look at the three example images below, for instance:

In some ways they’re nearly identical, with the same background image, colors, typeface and so on. But the second one is slightly different — it’s the kind of thing you might see when someone takes a screenshot and shares that instead of the original. The third is visually the same but the words have the opposite meaning.


An unsophisticated computer vision algorithm would either rate these as completely different images due to those small changes (they result in different hashes) or all the same due to overwhelming visual similarity. Of course we see the differences right away, but training an algorithm to do that reliably is very difficult. And the way things spread on Facebook, you might end up with thousands of variations rather than a handful.


“What we want to be able to do is detect those things as being identical because they are, to a person, the same thing,” said Schroepfer. “Our previous systems were very accurate, but they were very fragile and brittle to even very small changes. If you change a small number of pixels, we were too nervous that it was different, and so we would mark it as different and not take it down. What we did here over the last two and a half years is build a neural net-based similarity detector that allowed us to better catch a wider variety of these variants again at very high accuracy.”


Fortunately analyzing images at those scales is a specialty of Facebook’s. The infrastructure is there for comparing photos and searching for features like faces and less desirable things; it just needed to be taught what to look for. The result — from years of work, it should be said — is SimSearchNet, a system dedicated to finding and analyzing near-duplicates of a given image by close inspection of their most salient features (which may not be at all what you or I would notice).



SimSearc