I am still not sure but after seeing Schmidhuber's talk last week, I think it is being able to find regularities/patterns, resulting in a compressed representation that allows to understand and compress some aspect of the world, and building layers (abstractions) of those compressed representations. This allows you to navigate through very large search spaces much much faster.
It's a fascinating subject, and at the core of what we are. I recommend the film.
https://en.wikipedia.org/wiki/The_Man_Who_Knew_Infinity_(fil...
You don't need to explain every dendritic cluster in order to extract core, composable and generative abstractions useful enough to shorten time to understanding by orders of magnitude (discovery of zero vs how quickly it can be taught).