From the teacher:
My husband and I personally oppose spanking in general. Nonetheless, we were in agreement that - if our child repeatedly placed himself in a dangerous situation (e.g., running into the street) and the time-outs were proving ineffective - then we'd have no qualms about spanking him to create a "physical memory" to break him of the dangerous habit.
That is the Torah intention of corporal punishment - to create a physical memory to assist a person in breaking bad habits. Today, we have modern inventions (modern concepts developed through the scientific field of child psychology) to assist in breaking people of bad habits.
The Torah is NOT a science book. Torah-observant Jews are instructed to heed the advice of science experts in matters of science (including psychology).