Can social sciences contribute to the betterment of the humankind?

Based on the humankind's experience so far, it is highly doubtful that more social engineering, even of a more enlightened kind, would ever make much difference in how human societies work.  Plus ça change, plus c'est la même chose. Human group dynamic inevitably produces hierarchies, warring cliques, and waste. Simply improving living conditions does not result in better human beings, simply in more comfortable and more energy-intensive environments to produce hierarchies, cliques, and waste. Like Dostoyevsky once asked to the effect of  "what do you do once everyone's fed?" Real change starts only within.

Four best socio-psychological experiments

The four most beautiful and tale-teling experiments that combine the best of experimental science and participant observation are:

The Third Wave experiment

Blue Eyes, Brown Eyes

Stanford Prison Experiment  
Milgram Experiment

They all paint a rather bleak picture of the most of the humanity, however. Apparently, when given the chance most earthlings will turn into monsters. It is only their own pain or the fear of authority - God, government, parents - that keep most of them from that.

Interestingly enough, all the three experiments are considered controversial. All had to be terminated by emergency, as they, nearly or very much so, went out of hand - quite like actual life outside the ivory silo always does.