It is true that sometimes communication is not possible because of different facts such as:
A: Background knowledge: if there is communication between two or more people but they don’t share the same background, it is probably that a clash of knowledge would appear.
B: Assumptions: it is said in the Tolteic philosophy: 1st Agreement: “Don’t make assumptions”. If you create and state assumptions about what other people said, you will be misunderstanding many messages.
C: Dialect: sometimes this is a problem since there are some words that has a different meaning or they are pronounced differently so this, too, can create non-communication.
it explains in great detail what the propose of dopamine's is and what they do. so this would be the most logical. at least this is what I think. I'm no teacher lol. good luck