I think that the claim of people's attention span decreasing is true, but I don't think that we directly pin it on TikTok as there are other social media platforms that we spend hours a day on. The source that this article originally got it's information from seems reliable, but again it only talks about the decrease in attention spans over the years and not how they know that TikTok is directly at fault for that. For this article, I couldn't find any other projects from him, but the original source author has had many other articles published. This article is from 2022 and the original source is from 2021, so I would say that this news is outdated and there are many other articles who report the same claim from this time. I don't think that these claims are bias, however it has been very popular these last couple of years to blame the decline of the new generation on social media use, which I think is valid, but we can't blame it all on TikTok.