As one with a graduate degree in developmental psychology and as a long-time graduate student of cognitive psychology and cognitive science (and its theory, myself offering major critiques of such), and with some general knowledge of brain science development, I do have some proposals for things that can be reliably identified in the human and defined for an operational system of AI.
(1) There are basic memory processes that have notable constant features (e.g. working/active memory and short-term memory). Other aspects of memory (long-term memory, including the contextualizing background effects to working memory) do always change (sometimes even in big ways -- in stages -- qualitatively) with learning/development, but they do retain and have distinct types of characteristics. Thus we have a couple clear definables and other capacities which have more-or-less definable natures plus definable qualitative changes.
(2) What leads to the qualitative changes in the content-mutable aspects of memory (in particular long-term memory aspects) are the very factors (perceptual/attentional) that cause shifts in stages and that work hand-in-hand with all major conceptual learning (literally occurring at the same time). At first, these "embedded" aspects of perception/attention and some new major learnings are only sensorimotor, that is in the first year of so of life. Other stage-shifts involve perceptual (or perceptual/attentional) shifts and there are about 4 more of these but they are not just sensori-motor, as now conceptualized. These would be definable through eye-tracking research (just now possible) and would be expected to occur at approximately 2 yr., 4 yr., 7 yr. and 12 years of age. These perceptual/attention shifts not only intimately affect learning (occurring simultaneously with new, most-significant learning) but they [also (correspondingly)] alter the nature of the most-mutable LTM (e.g. episodic memory and spacial memory) .
These things, and somehow working in emotional patterns (less complex), would allow for an operational AI system to be much like a human (that is what is meant by AI, afterall). To learn more see my "A Human Ethogram and Development" Project -- esp. the 2 newest updates -- and see the major references of that project.