truly, Ranier Wolfcastle was the definitive Radioactive Man.
Visual tropes are as common as any. Once you know to look for 'em, you see 'em everywhere. Other examples are the use of white or black hats in westerns to denote good and bad guys (which was then turned on its ear in the 60's, but that only worked because it was a trope), or the use of cigarettes to denote an attitude of apathy (which is part of being "cool"), or even the type of weapon a character chooses to arm themselves with (revolver=cowboy, big guns=overpowering force, small guns=stealthy, etc).
Being able to recognize and manipulate visual tropes is an effective way for an artist to establish hints of character in a design. Accessories, fashion, body types, body language, all of them carry subtle hints based on shared popular culture.
Of course, when that crosses into cultures that don't share the same tropes, it can fall flat or even miscommunicate. Then the fun really starts.
That's interesting... of course I'm aware of most of those visual tropes, but up until now I hadn't really realized how prevalent they still were. I'm going to have to start keeping an eye out for those. In fact now I'm interested to see how many I'd find when taking a survey of the covers of the books I own...
All that being said, the shorthand of goggles=steampunk has really started to annoy me. I see way too many drawings and covers that have nothing to do with steampunk but still get labeled as such because someone wears goggles in them.
As an aside, the word "goggles" starts to look really funny when you type it too much. Goggles goggles goggles...