Juan will likely experience and elevation in his mood. If he is singing and optimistic song and eventually starts believing the words of the song, then Juan will start feeling better himself. It is very difficult to remain brooding when surrounded by something as optimistic as a 'Put on a happy face' song. And if Juan really wants to feel better, he will believe the lyrics and actually make his mood better.
The answer is attitude. Attitude is well defined as information
and good or bad feelings about something. In psychological studies, attitude is
referred to as a psychological construct, a mental and emotional entity or
persona which shapes a person. Attitudes can be attained by certain experiences
in one’s daily life.
