This neat University of South Carolina study suggests that pronouns actually help keep the brain from becoming overloaded:
The brain responds to proper names by creating a representation of the person in the mind, drawing from various parts of the brain to construct complex visual, sound and other information associated with that person. Every time the name is repeated, the brain responds by activating a process that creates a new representation of the person.
The brain initially holds each created representation in memory. The integration of these multiple representations requires effort that can disrupt the brain’s ongoing processing of what it hears during spoken conversation.
Pronouns, while faulty for their potential ambiguity, don’t cause the same disruptions in the brain that proper names do when used in the right context. In fact, they allow the brain to move easily from one thought or sentence to another. This seamless transition allows a person to digest more fully the meaning or intent of the thought being conveyed without the neural circuitry interference that proper names cause, said Almor.