How do professors and lecturers learn to teach? I am a PhD student in the field of education and I enjoy reading SE questions to stimulate my mind when I need a break. I find academia to be one of my most frequently visited sites.  

When reading questions, answers, and comments to questions of teaching practices I often see content I consider problematic given what is “known” (a word I will use loosely here) from research in educational psychology.  

How do professors and lecturers learn to teach?  

I do not mean this flippantly as I often see high-quality contributions on SE as well. 

I suspect teaching courses as doctoral students is a consistent practice across fields, but I am curious to know what accompanies this in fields outside of education.  What other resources are provided besides having professors and lecturers learn on the fly and make their own conceptions of what good teaching practices are?

I understand this may be largely field and institution dependent. I also am asking from a U.S. context, but I would be interested to know if the structure is noticeably different between countries.
This answer is based on my experience in Germany, and in an engineering field.


For interested teachers, universities usually have a central department that offers training, workshops, brochures, and plenty of information about how to teach. For example, here, here, and here. 
Many lecturers do not take advantage of these possibilities and still learn on the fly. Doctoral students often have recently attended master courses and observed how teaching was done there. In many cases, the professor gives the lectures and the doctoral student teaches the corresponding tutorial, which consists of doing practice exercises on the board. This is easier to do than teaching concepts, and provides an opportunity for the doctoral student to become confident in teaching.
Evaluation by the students also plays a role. The students are asked to give anonymous feedback on the lectures and tutorials approximately at the middle of the semester. The teacher can then learn what they can improve in their method of teaching.