What is the key feature of human learning? It is, I believe, the desire to learn. From a very young age, children are instinctively motivated to learn. Also, desire is often motivated by a payoff. My view of the human desire to learn tells me the payoff can be almost anything but the deeper factor--the fundamental factor--in learning is to want to learn.
It's a fact that our desire to learn is so pervasive that it is not always easy to see as separate from intelligence, which machines have already attained.
The current architecture of machine thinking, the so-called "stored program" computer, was an idea hatched by perhaps the greatest mind in history in terms of his personal learning; John von Neumann, during the ideastorm of WWII.
But there is no motivational factor in this universally copied machine thinking architecture.
The next architecture would, I think, ideally include the specific desire to add to its own architecture through the motivational system employed by humans.
There may be a quantum connection here. Many physicists have theorized that a machine observing a quantum experiment cannot collapse the wavefunction of a particle while human "observation" can.
Could the raw human desire for knowledge be the difference?