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Astral Codex Ten Podcast


Nov 1, 2018

[Epistemic status: fiction]

Thanks for letting me put my story on your blog. Mainstream media is crap and no one would have believed me anyway.

This starts in September 2017. I was working for a small online ad startup. You know the ads on Facebook and Twitter? We tell companies how to get them the most clicks. This startup – I won’t tell you the name – was going to add deep learning, because investors will throw money at anything that uses the words “deep learning”. We train a network to predict how many upvotes something will get on Reddit. Then we ask it how many likes different ads would get. Then we use whatever ad would get the most likes. This guy (who is not me) explains it better. Why Reddit? Because the upvotes and downvotes are simpler than all the different Facebook reacts, plus the subreddits allow demographic targeting, plus there’s an archive of 1.7 billion Reddit comments you can download for training data. We trained a network to predict upvotes of Reddit posts based on their titles.

Any predictive network doubles as a generative network. If you teach a neural net to recognize dogs, you can run it in reverse to get dog pictures. If you train a network to predict Reddit upvotes, you can run it in reverse to generate titles it predicts will be highly upvoted. We tried this and it was pretty funny. I don’t remember the exact wording, but for /r/politics it was something like “Donald Trump is no longer the president. All transgender people are the president.” For r/technology it was about Elon Musk saving Net Neutrality. You can also generate titles that will get maximum downvotes, but this is boring: it will just say things that sound like spam about penis pills.