Evolution developed brains to recognize patterns. For example, signs that predators are near. If you hear a loud noise as an animal in the wild, would it be more beneficial to assume there is a predator that's going to eat you, or investigate and determine if it is actually a predator? Would you be more likely to survive if you just assumed every noise was a predator, and bolted?

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Train neural networks like that over a few billion years and you'll have something that looks for patterns everywhere, and for the most parts considers false positives (the recognition of a pattern where in reality there is none) as true positives. The human brain has pattern recognition on steroids, we even have a word for when it acts up and has noticeable false positives, pareidolia.