What did Wundt's pendulum experiment demonstrate?

a 10th of a second delay between hearing the bell and noting the position of the pendulum (and vice versa)

Explanation:

Using a pendulum that hit a bell upon reaching its outer limits, Wundt demonstrated a 10th of a second delay between hearing the bell and noting the position of the pendulum (and vice versa), and it was during that very brief period that a mental process occurred.