When I am teaching, I introduce myself as "Professor Palmer". Doing so implies, I think, that I would like students to address me that way.
I didn't always feel this way. When I was young, I listed my first and last names on the reading lists and invited students to call me "John". After all, I was close to them in age and was socially much closer to them than I am now.
I also asked members of the secretarial staff to call me "John", but they politely refused, insisting on calling me "Professor Palmer".
Somewhere in my late 50s, I began to feel a social and cultural distance from my students. It no longer seemed appropriate for the students, especially undergraduates, to call me by my first name. They always knew my first name from my blog work and from my academic website, but on reading lists and exams, I listed my name as "Professor J. Palmer."
From time-to-time, a student would nevertheless call me "John" or ask if they could call me "John". I would react with a bit of surprise and say "ok" in a clearly unconvincing way. Some persisted; others did not. I am not a buddy or friend (at least not yet when they are undergrads taking a course from me), I am their professor.
When they are no longer my students, I ask my former students to call me "John". Some do, others find it difficult (typically these students were raised in more formal, traditional cultures).
As an undergrad, I attended Carleton College, which had many Harvard-like traditions, including proper address of the faculty members: they were Mr., Miss, or Mrs. (and many females there are probably Ms. now); we were instructed not to address them as Dr. or Professor.
At Chicago Theological Seminary, and later at Iowa State University, our professors were addressed as Dr. And even at Iowa State, until the last term of my last year in gradskool, after I had accepted a job offer from UWO, I was reluctant to call professors by their first names.
Here is what prompted this recollection: An article a week or so ago in the WaPo in which it was pointed out that US President Obama liberally referred to Germany's Chancellor Angela Merkel as "Angela" while she fairly consistently referred to him with a more formal term of address.
My jaw hit the floor when I read the president referring to the chancellor, Angela Merkel, as “Angela.” Surely the reporter got it wrong. So I went to the White House transcript, and was horrified to see that the president referred to the chancellor by her first name nearly two dozen times. The opening paragraph alone is littered with informality. “Angela, of course, has been here many times.” “Well into her third term, Angela is now one of Germany’s longest-serving chancellors.” “As we all saw in Rio, Angela is one of her team’s biggest fans.”...
“Angela?” My goodness. “Ms. Merkel,” “the chancellor,” “Chancellor Merkel” (if that usage is permitted in Germany), “madam chancellor” or “Dr. Merkel” would be fine. But “Angela?”
Maybe I am just a stuffed shirt and out of touch with current norms, but I agree with this writer. Go more formal until invited to do otherwise. For example:
I recall a recruiting trip I took back in 1970. I addressed the person greeting me at the airport as Dr. _____ and was promptly told to call him by his first name.
That seems more comfortable and more appropriate to me.