I'm sure studies have been done, but I wonder just what sensory triggers are in play here. For me it's there or it's not there, and there's really no predicting it; is that how it is for everyone?
I think it depends on the person.
I'm not even sure it's the same all the time for each person. I'm looking back on my IRL crushes...and they were across the board in high school. There was one guy who wasn't physically attractive at all, but man could he make me laugh! He was goofy and funny and at times obnoxious, yet I had a mild crush on him.
There was one guy - an actor who shall remain nameless - who also wasn't what you'd think "hot" at ALL. Short, round face, cute maybe but looking about 12 when we graduated. Yet he had major talent (singing and acting) and was majorly smart, and all that turned me on.
There were also guys that were conventionally attractive, but even in real life, those aren't ALWAYS the ones that smack me upside the head.
My ex-husband had nice dimples when he smiled and pretty eyes, but he carried a good 25 pounds more than he should have (at least by the time we divorced). His dimples and outgoing-ness got me (too bad I realized too late exactly how outgoing he was...if you get my drift).
My current husband, when we met, was just plan tall and gorgeous. He's put on some weight now, but he's working to lose it. But what really got me was his love for his daughter, his loyalty to his family and close friends, and his dedication to providing and protecting us.
So sorry for the long ramble, but you got me thinking.
And I think best out loud. On a writing forum, out loud = typing on the screen.
I don't think I really answered your question.