There's already a lot of discussions re: other aspects of screen time here, so I'd just like to touch on exactly what is on this study -- ability to search for things faster after "screen training". (like faster reflexes)
Before anyone takes this study and says "so screen time has positive influence" and gives it to their 1 year-old, I'd like to give an anecdote from my own experience. I grew up in the 80s and my family was one of the earliest to own an NES. According to my parents, I started playing the NES when I was 4 or 5. I have some of the fastest reflexes (when it comes to video games or similar activities) of any friends I know; and I played in fighting games tournaments in college. This is a genre of competitive games where millisecond-reflexes can determine the outcome of the game. (of course, I was a low tier tournament player and there are tons of world class players way better and faster than me)
I'd say my takeaway is that sure, maybe that kind of "screen training" helps with reflexes and attention, but you don't have to start that early. If you start at 5 years old instead of 1 year old, you might just get as much of the benefits, without the down sides of vision problems etc. that comes with having screen time too early.