"Linear" meaning closely mimicking human learning. No one reads two books at the same time. Or a movie and a radio program. Or drive a car while threading a needle. In theory a modern computer can do all of this without breaking a sweat. So our computers are not a linear learning model but logarithmic (accounting for heat & power)
Our consciousness tends to drift from one to the other. Even people who claim to be multitaskers, it's been proven that they simply switch back & forth at opportune times.
Eg, biological creatures are sequential learners. So linear seems appropriate.
But I'm years from publishing this, so I have time to re-invent the acronyms