In a cartoon by the Farside cartoonist Gary Larson, a bug-eyed school kid asks his teacher, "Mr. Osborne, can I be excused? My brain is full!" If you're just engaging in mechanical repetition, it's true, you quickly hit the limit of what you can keep in mind. However, if you practice elaboration, there's no limit to how much you can learn. Elaboration is the process of giving new material meaning by expressing it in your own words and connecting it with what you already know. The more you can explain about the way your new learning relates to your prior knowledge, the stronger your grasp of the new learning will be, the more connections you create that will help you remember it later.
There's virtually no limit to how much learning we can remember as long as we can related it to what we already know. In fact, because new learning depends on prior learning, the more we learn, the more possible connections we create for further learning. Our retrieval capacity, though, is severely limited. Most of what we've learned is not accessible to us at any given moment. This limitation on retrieval is helpful to us: if every memory were always readily to hand, you would have a hard time sorting through the sheer volume of material to put your finger on the knowledge you need at the moment.
Peter C. Brown and Henry L. Roediger III, Make It Stick: The Science of Successful Learning