To me this model feels a bit too simplistic. If you only look at how children learn their abilities, then yes, absolutely. Where it breaks down for me is in the interaction with play partners. The joy he seems to get for playing together doesn't seem to be fully explainable through pure evolutionary steering / fitness functions, but it's hard to put my finger on what's missing in the picture. An example is his joyful giggling when I'm doing something unexpected. You can see the tug of war between fearfulness and joyfulness - at the beginning when they become sensitive to playful behavior it makes them afraid, but more and more this is replaced with pure joy, also showing a trust relationship. So to me it seems the curiosity goes beyond just what the child can achieve him/herself in the near future, it's also a curiosity and joy of observing the world, and more importantly, what the caregivers are doing. Everything new is exciting, and much of it doesn't seem to be something that could have been selected for directly. So there seems to be some emergent behavior that comes from the interaction of evolved chemistry/signaling, and the actual cognitive functions.
Unknown things are to be avoided, until feedback shows that there's no threat, which makes aversion costly. Then simple observing is the lowest cost option until there's fewer novelties. The extra energy expended from interaction is then offset by the gains in feedback. Eventually even that peters out and finding something else to do makes more sense.
