Answer:
Facial feedback hypothesis
Step-by-step explanation:
The facial feedback hypothesis states that facial expressions and movement can influence emotions. This theory states that our facial movements send messages to the brain and this creates a process of feedback in which our brain influences our emotions.
For example, if I fake a smile for some time, my face muscles send this information to the brain and I will end up feeling happy and smiley.
In the question, Professor Petterson is actually teaching his class about how facial expressions provide feedback to the brain which then causes emotions, this is actually what we just explained about the Facial Feedback hypothesis.