In the science of pedagogy (teaching/learning) it is important to have a system of how you understand the world around you so that you can use this understanding to filter all the information that you take in. To assimilate means to apply new ideas into your pre-existing frame-work so that your system for analyzing the world around you is more reflective of what and how other people are seeing their physical environments.

http://authorandgrowrich.com/blog/this-was-actually-written-above-the-urinal-in-the-boys-bathroomglenn