I don't know if any psychologists actually use this term, but it's something I came up with today.

Things like a photograph, a flag, an archetype, a thought, an event, form SYMBOLS in the human mind. Symbols are ways of organizing complex psychological associations for specific memories, events, hopes, different layers of meaning. An alphabet is a series of symbols, collectively forming words and phrases that form yet more complex symbols. This is how the human mind arranges things.

This also explains how apparently simple things can unexpectedly activate powerful patterns of thought, emotion and behaviors in people. Symbols can be triggering, unless one takes a slightly different look at a triggering symbol, to somewhat alter its meaning or amplify or reduce its power. So, understanding this can be a useful tool for reorganizing your mind - or for that matter, better communicating with others as well.

Edit: the closest related psychological concept I have found is "Object Relations Theory", but my idea of symbols is a lot more generalized than that.