There's a lot of buzz and fuzz about the icon usage for an accordion header (state changing button).
After a short research, I came to the conclusion to use up and down arrows and I was wondering if anyone can provide a better reasoning about icons usage for this matter.
My logic when choosing this option (up and down arrows) was the following:
When I see a down arrow, I expect something to happen in this direction (from top to bottom). The same logic applies for the up icon;
I rejected the idea of using +/- symbols since the action of expanding/collapsing doesn't relate to addition/subtraction symbols.
I also wanted to keep things consistent, as we had some drop-down menus which use the same arrow approach.
There was one more variation: using the greater than symbol for initial state (collapsed) and the up arrow for expanded state. I also find this approach a little bit confusing, since the left arrow and right arrow symbols make more sense when having a left-to-right navigation or a step-by-step action.
Does any of you know a better/intuitive aproach for this matter?