Final answer:
Psychology replaced philosophy as the dominant approach to teacher training in the 19th century.
Step-by-step explanation:
In the 19th century, psychology replaced philosophy as the dominant approach to teacher training.
As academic disciplines professionalized and specialized, investigations that were traditionally part of philosophy, including matters of the mind, became separate disciplines.
Psychology focused on the study of human behavior and cognition, making it a suitable replacement for philosophy in teacher training.