Question

Researchers found that happiness predicted bigger increases in income, while higher income did not predict increases in happiness. what was the best explanation for the former?

Answer 1

Once someone's happy, he/she can now think beyond just his/her own needs. They will start thinking about other people's needs and try to help, which is needed by many people who will return the favor in terms of money. Also when someone's happy, that person becomes more attractive to other people and people want to be around them, hire more radily,recommend to others, etc.
Just my thoughts