You could even reduce all perception to symbolism, but it is kind of hard to do that at the level of reactions and reflexes. I don't think of it this way. Expressions are of course subjective as they emerge from a context, a situation, and a particular person's perspective. It is hard to call them objects as they are part of ongoing discourse and interaction. Even if you took a photo, you would be cutting out the temporal context.
Expressions refer to meanings.
In this sense, I have to switch gears.