Some people think of Hugo Weaving as Agent Smith. Some people think of him as Elrond. You can tell a lot about a person by which it is. Presumably there are people who think of him as V or even Johann Schmidt. Personally, I’ve seen him as Mitzi the Magnificent since the mid-’90s, and I’d be impressed if any role came along, ever, to change my opinion of that. That’s fine. That doesn’t make me better or worse than anyone; it’s just my familiarity with a specific role and my fondness for it. There are a lot of actors like that, where a single role is enough to crystallize them in your mind—but there are plenty of roles in the person’s career to go around, and if you don’t see one, you’ll see another.
They come up a lot in the weekend columns. Edward Herrmann, Ron Perlman, Carel Struycken, Matt Frewer, and so forth. They’re not all men, of course. Annette Funicello probably qualifies. Jodie Foster, definitely. Tilda Swinton, like as not. These are people who so inhabit their various roles that it doesn’t matter what they’re playing. You picture them in the role not just because they’re good in the role but because they’re distinctive. You remember them, and you remember them in a specific role.
Further, this isn’t remembering Alan Alda as Hawkeye Pierce. This is remembering James Garner as Jim Rockford or Bret Maverick or Jason McCullough—there must be at least two or three roles to choose from. If you’re someone who pictures Alan Alda as Dr. Gabriel Lawrence or even his Oscar-nominated role of Senator Ralph Owen Brewster, you know you’re in the definite minority. There’s got to be dozens of you. But the distinction here is that someone like Garner has multiple roles to choose from where it’s perfectly reasonable to picture them in it.
Honestly, from M*A*S*H, there are a few worth choosing between. Harry Morgan’s Colonel Potter, to be sure. But also there’s Dragnet and Bill Gannon. There’s the assorted Disney roles he portrayed. Heck, he was in Support Your Local Sheriff right along with James Garner. Admittedly, he’s about the only one of the main cast like that; you might know David Ogden Stiers for his voice work, but it’s not quite picturing him. Still, there were plenty of guest stars who could fit the bill nicely. Leslie Nielsen. Laurence Fishburne. Edward Herrmann again, in fact.
Most of the litmus roles come from character actors. When you think of Thelma Ritter, it may be from Vertigo or How the West Was Won or Miracle on 34th Street. When you think of Cary Grant, it may be from North by Northwest or Charade or Father Goose, but in first and foremost you think of him as Cary Grant. By and large, litmus roles aren’t for movie stars but for people you’re just used to seeing. That’s okay; there’s nothing bad about it. They’re just an interesting quirk of how humans remember other humans, especially ones they know from fiction.