If whatever learning meant +1 brain complexity then it we would never catch up because it would be the infinite hotel. example: learning one unit of brain complexity adds one unit of brain complexity.
if learning meant < +1 brain complexity, then the next limiters would be brain space and time. example: learning one unit of brain complexity slightly complicates an already existing complex.
if learning meant > +1 brain complexity, then the more you learn, the farther you get from understanding the whole thing. example: learning one unit of brain complexity requires the addition of another unit of brain complexity plus its relationship with other complexes.