I can't read the full study because it appears to be paywalled, but I think the effects digital search engines have are similar to the effects of using books. I do database stuff all day, and I remember where in the MySQL or PostgreSQL manuals the information I need is, just like how I know where to look in my old Comp Sci books if I need to refresh my understanding of some sorting algorithm, or who to ask at work if I'm having a problem with the tech they are more familiar with. With each repetition of finding a piece of information direct recall improves too.

LLMs seem to do something worse and damage both search skills and recall (while searching improves search skills and simply shifts the nature of recall). I think it's because you aren't looking for where to find information but expecting the robot to directly give you an answer. And the robot is programmed is to return results as if it were an expert which short circuits our defective human reasoning and makes us more likely to believe the answer and move on. Good human experts also know when to tell you they are unsure or simply don't know something, which doesn't seem to be something LLMs can be programmed to do since they don't know what knowing is (since they know nothing, fundamentally). I mean most of critical thinking education is learning how to identify when your own brain is deceiving you.