These experts in machine learning argue that learning from teachers first requires you to learn about teachers. For example, if you know how teachers work, you tend to assume that they are trying to be informative. When the teacher in the tube-toy experiment doesn't go looking for hidden features inside the tubes, the learner unconsciously thinks: "She's a teacher. If there were something interesting in there, she would have showed it to me." These assumptions lead children to narrow in, and to consider just the specific information a teacher provides. Without a teacher present, children look for a much wider range of information and consider a greater range of options.
Knowing what to expect from a teacher is a really good thing, of course: It lets you get the right answers more quickly than you would otherwise. Indeed, these studies show that 4-year-olds understand how teaching works and can learn from teachers. But there is an intrinsic trade-off between that kind of learning and the more wide-ranging learning that is so natural for young children. Knowing this, it's more important than ever to give children's remarkable, spontaneous learning abilities free rein. That means a rich, stable, and safe world, with affectionate and supportive grown-ups, and lots of opportunities for exploration and play. Not school for babies.
Correction, March 17: This sentence originally omitted the names of two of the study's researchers. (Return to the corrected sentence.)