As far as I'm aware, this is not true at all. Adults actually learn considerably faster per hour spent, it's simply that most adults don't have as much time to dedicate to learning as kids do. This is confirmed both by studies as well as intuition — you get better at most things as you do more of it, studying is the same.
DrScientist|12 days ago
Whether it's something completely new and alien - in which case children might be better, or whether it's learning through association - ie I understand that because I can connect it to previously learnt concepts ( which would favour people with more previous knowledge ).
For example, something like maths is often seen as a young persons game, but at the same time you probably don't want a 14 yr old running your company.