Advanced artificial intelligence is capable of level of pattern-finding and problem-solving that most people can barely even comprehend, but that doesn’t mean the technology doesn’t have a ways to go. Sometimes, even the most intelligent computers make mistakes that not even the dumbest human would, such as calling black people “gorillas.” Google had to learn that lesson the hard way earlier this week.

Google is a leader in artificial intelligence and machine learning. But the company’s computers still have a lot to learn, judging by a major blunder by its Photos app this week. The app tagged two black people as “Gorillas,” according to Jacky Alciné, a Web developer who spotted the error and tweeted a photo of it. “Google Photos, y’all f**ked up. My friend’s not a gorilla,” he wrote on Twitter. Google apologized and said it’s tweaking its algorithms to fix the problem. “We’re appalled and genuinely sorry that this happened,” a company spokeswoman said. “There is still clearly a lot of work to do with automatic image labeling, and we’re looking at how we can prevent these types of mistakes from happening in the future.” The gorilla tags turned up in the search feature of the Google Photos app, which the company released a few weeks ago. When users start a search, Google suggests categories developed from machine learning, the science of training computers to perform human tasks such as labeling. The company has removed the gorilla categories, so those suggestions will no longer appear.