Depends on the person.
This holds true for every theory. But I guess the basic idea is that people judge themselves by the reaction from their surroundings, in this case- the society.
Lack of negative feedback is in no way the only factor in overconfidence. Too much of a positive feedback will also give overconfidence. But this theory is from a different perspective. Its just trying to point out that we are reluctant to give negative feedback and people might take it in a different way. I have to say that I do not totally agree with this view because I feel, unless you get positive feedback or what you can call "appreciation", we don't feel motivated to do better. How can a neutral situation make anybody overconfident ?
Anyways, people will continue to make radical attempts to understand society. This is a weak one.
"Love may fail, but courtesy will previal." -- A Kurt Vonnegut fan