I didn’t know anything about this particular author/journalist. Wow was his wikipedia full of reasons never to trust this guy. For this book alone, criticism:

Scientists Stuart Ritchie and Dean Burnett both criticised the book for failing to cite strong evidence for the claim of shrinking attention spans, as well as presenting mainstream psychological concepts as niche ideas that Hari had discovered.[67] Writer/broadcaster Matthew Sweet investigated some of the claims in the book and found that Hari had failed to cite the primary sources for some studies, and misrepresented the results of studies that suggested multitasking could have benefits in certain conditions.