more happy or happier

I found this article in VOA, that is similar to RTVD in dominican republic but in USA where they use both more happy or less happy. It clarifies that it's not forbidden its use and that you can use it depending on context.

 "Are people less happy or more happy the older they get? If you answered more happy, then you were right, based on a study published two years ago. It found that people generally become happier and experience less worry after age fifty. In fact, it found that by the age of eighty-five, people are happier with their life than they were at eighteen".
I find that this reading is very interesting, isn't it?

VOA offers resources for learning English, you can visit its website or find it in YouTube, just type voa.