The only "scientific" reason kids (and women) catch more at times is their lower levels of L-serine. That's a chemical that we produce that can repel fish, and men tend to have more of it. Dr. Juice did major studies on it, possibly Berkley too.

Unscientifically, I've decided thru 50 years of fishing and observing that newbies do better because they BELIEVE they will catch fish, rather than complicating the sport with mega-doubts over the wrong lure color, fly pattern, cold fronts, moon stage, etc., etc.! You take these kids/newbies out and they are "positive" they will catch fish. There's a book called "Positive Fishing" by Robert Deindorfer (1981), probably hard to find, but worth looking for.