TikTok is the most successful app in history:
It emerged in 2017 out of the Chinese video-sharing app Douyin and within three years it had become the most downloaded app in the world, later surpassing Google as the world’s most visited web domain.
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Other platforms, like Facebook and Twitter, use recommendation algorithms as features to enhance the core product. With TikTok, the recommendation algorithm is the core product. You don’t need to form a social network or list your interests for the platform to begin tailoring content to your desires, you just start watching, skipping any videos that don’t immediately draw your interest. Tiktok uses a proprietary algorithm, known simply as the For You algorithm, that uses machine learning to build a personality profile of you by training itself on your watch habits (and possibly your facial expressions.) Since a TikTok video is generally much shorter than, say, a YouTube video, the algorithm acquires training data from you at a much faster rate, allowing it to quickly zero in on you.
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In order to develop and maintain mental faculties like memory and attention span, one needs to practice using them. TikTok, more than any other app, is designed to give you what you want while requiring you to do as little as possible. It cares little who you follow or what buttons you click; its main consideration is how long you spend watching. Its reliance on machine learning rather than user input, combined with the fact that TikTok clips are so short they require minimal memory and attention span, makes browsing TikTok the most passive, uninteractive experience of all major platforms.
If it’s the passive nature of online content consumption that causes atrophy of mental faculties, then TikTok, as the most passively used platform, will naturally cause the most atrophy. Indeed many habitual TikTokers can already be found complaining on websites like Reddit about their loss of mental ability, a phenomenon that’s come to be known as “TikTok brain.”