Both happens. Some studies such as [1] measure recommendations without past browsing history, and they still find recommendations for harmful content. Other s

Both happens. Some studies such as [1] measure recommendations without past browsing history, and they still find recommendations for harmful content. Other studies (such as this from Berkman Klein Center [2]) simulate user behavior and subsequent recommendations and find additional harmful effects of personalized recommendations. [1] Faddoul, M., Chaslot, G., & Farid, H. (2020). A Longitudinal Analysis of YouTube’s Promotion of Conspiracy Videos. ArXiv:2003.03318 [Cs]. http://arxiv.org/abs/2003.03318 http://arxiv.org/abs/2003.03318 [2] https://cyber.harvard.edu/story/2019-06/youtubes-digital-playground https://cyber.harvard.edu/story/2019-06/youtubes-digital-pla...